nutrient fluxes in multitrophic aquaculture systems - Institut für ...

Aus dem Institut für Tierzucht und Tierhaltung
der Agrar- und Ernährungwissenschaftlichen Fakultät
der Christian-Albrechts-Universität zu Kiel
NUTRIENT FLUXES IN MULTITROPHIC
AQUACULTURE SYSTEMS
Dissertation
zur Erlangung des Doktorgrades
der Agrar- und Ernährungwissenschaftlichen Fakultät
der Christian-Albrechts-Universität zu Kiel
vorgelegt von
Master of Science
YUDI NURUL IHSAN
aus Bandung - Indonesien
Kiel, 2012
Dekanin: Prof. Dr. K. Schwarz
Erster Berichterstatter: Prof. Dr. C. Schulz
Zweiter Berichterstatter: Prof. Dr. E. Hartung
Tag der mündlichen Prüfung: 09.02.2012

Gedruckt mit Genehmigung der Agrar- und Ernährungswissenschaftlichen
Fakultät der Christian-Albrechts-Universität zu Kiel
II

Table of Contents
General Introduction ....................................................................................................... 1
Chapter 1:
Nutrient flux in polyculture system using seaweed as biofilter: Implication for
sustainability............................................................................................................... 5
Chapter 2:
A Comparison of nutrient fluxes in monoculture and polyculture systems for
shrimp (Penaeus vannamei) and seaweed (Gracillaria verrucosa) production...... . 20
Chapter 3:
Nutrient Fluxes and Mass Balances in Various Polyculture Systems Using
Shrimp Penaeus vannamei, Fish Oreochromis sp. and Seaweed Gracillaria
verrucosa................................................................................................................. 46
Chapter 4:
Nitrogen Assimilation Potential of Seaweed Gracillaria verrucosa in
Polyculture with Pacific White Shrimps (Penaeus vannamei) .............................. 74
General Discussion ...................................................................................................... 95
General Summary......................................................................................................... 102
Zusammenfassung........................................................................................................ 104
Danksagung.................................................................................................................. 107
Lebenslauf.................................................................................................................... 108
III

General Introduction
The marine sector including aquaculture is one of the leading sectors in economic
development in the world. Aquaculture contributes significantly to food
availability, household food security, income generation, trade, and improved
living standards in Indonesia. In poor rural communities, aquaculture can be an
integral component of development contributing to sustainable livelihoods and
enhancing social well-being. Since 1990 the gap between the demand for and
supply of fish has been widening rapidly due to the decline of capture fisheries
production and a continually growing population. Aquaculture is forecasted to
dominate, if not surpass, the importance of marine capture fisheries in providing
high quality animal protein to lower income groups, employment, and export
earnings.
Indonesia has good fisheries and aquaculture potential. Because of its rich, coastal
and marine resources suitable for aquaculture development, it is one country
where aquaculture can contribute to economic and social development goals. The
potential area for aquaculture is estimated at about 26 million hectares (ha),
consisting of 24.5 million ha of coastal areas suitable for mariculture, 913
thousand ha of brackish water areas, and 1.1 million ha of freshwater areas.
Actual area coverage of aquaculture is currently estimated at only 681 thousand
ha, corresponding to less than 3% of the total potential area.
The contribution of fish to global human food supply has reached a record of
about 17 kg per person in average, supplying over three billion people with at
least 15% of their average animal protein intake (FAO, 2010). Marine aquaculture
has been a rapidly growing industry, increasing from about 18.6 million tons in
2006 to 20.1 million tons in 2009 and these patterns are expected to continue up to
2030 due to the increasing global demand and high market value of aquaculture
products (FAO, 2010). Global production of shrimp has increased by more than
600% between 1989 and 2009 and is expected to continue due to the high market
value of cultured shrimp. This production comes from a variety of farms ranging
from small-scale ponds to large-scale ponds.
As a result of the rapid production increase, it is not unreasonable to conceive that
aquaculture activities might affect the environment in a variety of ways, especially
1

fish and shrimp aquaculture which need to supplemented with an exogenous
source of nutrients. Increased production is being achieved by expansion of land
and water areas under culture and involve higher utilization of production inputs
such as water, feeds, fertilizers, and chemicals. Higher inputs normally affect the
surrounding environment in a number of ways. Particular concern arise by the
effects of particulate nitrogeneous wastes produced by the ponds in the form of
uneaten feed and fish faeces (Pearson and Gowen, 1990; Troell et al., 2003).
Poorly managed coastal shrimp farms have been cited for degrading nearshore
habitats through nutrient enrichment (Boyd, 1999; Hargreaves, 1998). Nutrient
enrichment could also affect the shrimp farms themselves through self-pollution.
Poor water quality may reduce farm productivity by diminishing shrimp growth
and/or promoting shrimp disease outbreaks (Hargreaves, 1998; Lin, 1989).
Identifying aquaculture species and system that are expected to be profitable is an
essential step toward developing sustainable aquaculture and to decrease the
adverse impact (Andersen, 2002 in Leung et al., 2007). Asian countries have been
practicing polyculture systems, through trial and error and experimentation for
centuries (Qian et al., 1996). These strategies were motivated by the need to
maximize productivity per unit of land and water bodies. They were based on
diversified self-reliance in feed and basic raw material production and the
philosophy that the by-products (wastes) from one resource use must become an
input of another resource in use (Chopin et al., 2001; Neori et al., 2004). On the
other hand polyculture has disadvantage as it could decrease main target
organisms production due to competition in space and nutrient utilization with cocultured
organisms.
Shrimp Penaeus vannamei, seaweed Gracillaria verrucosa and fish Oreochromis
sp. had been used in presented thesis due to the different trophic level they
inhabitated, the high economic value, and well developed knowledge of
cultivation. Hypothesis of this study are: (1) nutrient given to the ponds can be
used most efficiently by polyculture system, (2) polyculture system using shrimp,
seaweed and fish can be used to minimize adverse impact of aquaculture to the
environment, (3) seaweed Gracillaria verrucosa can be used to absorb nutrient
excretion from shrimp and fish wastes and may contribute to the oxygen budget.
2

To prove this hypothesis, in Chapter 1 of present study, based on a literature
review polyculture system can be described as the practice of culturing more than
one aquatic organism in the same system. In Chapter 2, empiricial calculations of
nutrients fluxes and mass balances in monoculture and polyculture systems with
shrimp Penaeus vannamei and seaweed Gracillaria verrucosa were realized and
compared. Additional investigations were conducted in Chapter 3 to determine
nutrient fluxes and mass balances in various polyculture systems using shrimp
Penaeus vannamei, Fish Oreochromis sp. and Seaweed Gracillaria verrucosa.
Finally, in Chapter 4, nitrogen assimilation potential of seaweed Gracillaria
verrucosa in polyculture with pacific white shrimps Penaeus vannamei was
estimated.
References
Boyd, C. E. 1999. Codes of Practise for Responsible Shrimp Farming. Global
Aquaculture Alliance. St. Louis MO. USA. 48.
Chopin, T., A. H Buschmann, C. Halling, M Troell, N Kautsky, A. Neori, G.
Kraemer, J. Zertuche-Gonzalez, C. Yarish, C. Neefus. 2001. Integrating
seaweeds into aquaculture systems: a key towards sustainability. J Phycol
37:975–986.
FAO. 2010. The state of world fisheries and aquaculture. Fisheries and
aquaculture department. Food and Agriculture Organization of United
Nations. Rome. Italy.
Hargreaves, J.A. (1998). Nitrogen biogeochemistry of aquaculture ponds.
Aquaculture 166, 181–212.
Neori, A., T. Chopin T, M. Troell, A. H. Buschmann, G.P. Kraemer, C. Halling,
M. Shpigel, C Yarish. 2004. Integrated aquaculture: rationale, evolution
and state of the art emphasizing seaweed biofiltration in modern
mariculture. Aquaculture 231:361–391.
Pearson, T. H., and R. J. Gowen. 1990. Impact of caged fish farming on the
marine environment – the Scottisch experience, 9-13. In interactions
between aquaculture and the environment, vol. An Taisce - The National
Trust for Ireland, Dublin.
3

Troell M, C. Halling, A. Neori, T. Chopin, A. H. Buschmann, N. Kautsky, C.
Yarish. 2003. Integrated mariculture: asking the right questions.
Aquaculture 226:69–90.
Qian, P. Y., C. Y. Wu, M. Wu, Y. K. Xie. 1996. Integrated cultivation of red alga
Kappaphycus alvarezii and the pearl oyster Pinctada martensi.
Aquaculture 147: 21-35
4

Chapter 1: Nutrient Flux in Polyculture System Using Seaweed as
Biofilter: Implications for Sustainability (Mini Review)
Y. N. Ihsan ab , K. J. Hesse c , C. Schulz ab
a Gesellschaft für Marine Aquakultur mbH, Hafentörn 3, D-25761 Büsum
b Institute for Animal Breeding and Husbandry, Christian-Albrechts-Universität
D-24098 Kiel
c Research and Technology Centre, Christian-Albrechts-Universität
D-25761 Büsum
Submitted to the Journal of Asian Fisheries Society
5

Abstract
In general, feed based shrimp and fish aquaculture can produce a large amount of
waste, including nitrogen and phosphorus that is released to the aquatic
environment without treatment. One of the main environmental issues is the direct
discharge of significant nutrient loads into coastal waters from aquaculture ponds
system. In its search for best management practices, the aquaculture industry
should develop innovative and responsible practices that optimize its efficiency
and create diversification, while ensuring the remediation of the consequences of
its activities to maintain the health of coastal waters. At present, seaweed
cultivation in integrated polyculture system appears to be a viable approach to
reduce discharge nutrients to the environment. By integrating fed aquaculture, the
wastes of one resource user become a resource for the others (Neori et al., 2004).
Seaweed can be efficient at removal of nutrients from effluent of intensive fish
farm (Troell et al., 1997; Neori et al., 2004). The production of seaweed in cage
culture can be successfully integrated with production of fish and shrimp.
Regarding the environmental benefits of integrated seaweed and fish or shrimp
production, seaweed culture can also benefit by increasing their economic
viability. Integrated seaweed aquaculture systems have been suggested as a
possible solution for securing an increasing and environmentally sounded
production of future supply of fish and seafood.
6

Introduction
Aquaculture has expanded rapidly all over of the world, especially in tropical
areas which account for 89% of production in terms of quantity and 79% in terms
of value (FAO, 2010). Aquaculture production (excluding seaweed) was less than
1 million tons per year in the early 1950, production in 2008 already achieved
52.5 million tons, with a value of US$ 98.4 billion. Seaweed production by
aquaculture in 2008 was 15.8 million tons (live weight equivalent), with a value
of US$7.4 billion, representing an average annual growth rate in terms of weight
of almost 8% since 1970. If seaweed is included, total global aquaculture
production in 2008 amounted to 68.3 tons with a first-sale value of US$ 106
billion (FAO, 2010). It is expected that world aquaculture production will
continue to grow in the coming decade. Aquaculture is a source of income and
livelihood for millions of people around the world. Employment in fisheries and
aquaculture has grown substantially in the last three decades, with an average rate
of increase of 3.6% per year since 1980 (FAO, 2010).
The expansion of aquaculture has brought concern about the possible effect of
aquaculture effluents on coastal ecosystem. Aquaculture has contributed to
environment degradation, with visible effect such as increases in particulate
organic matter and chemical change such as dissolved oxygen reduction and
increased nitrogen and phosphorus concentrations in water (Troell et al., 1999).
The negative impact of aquaculture on the environment due to the release of
nitrogen and phosphorus is related to eutrophication processes, especially in
coastal and sheltered areas (Neori et al., 2000; Neori and Shpigel, 2003). This
nutrient release is primarily caused by intensive and semi intensive production of
fish. Feed and fertilizer which are applied in ponds are not fully incorporated into
the cultured species partly deposited in pond sediments or discharged as effluents.
In average, fish or shrimp assimilates only 23-31% of nitrogen and 10-13% of
phosphorus of the total inputs and remaining 14-53% of nitrogen and 39-67% of
phosphorus are deposited in the sediment (Neori et al., 2000; Dhirendra and Lin,
2002; Schuenhoff et al., 2003). Nutrient in aquaculture effluents are distributed in
a particulate or soluble fraction (Ackefors and Enell, 1994). In fresh manure,
about 7-32% of total nitrogen (TN) and 30-84% of total phosphorus (TP) are
7

ound in this particulate fraction and the remainder are excreted in dissolved
forms (Bergheim et al., 1993). In intensive marine shrimp culture, only 24% and
13% of dietary nitrogen and phosphorus were incorporated into harvested shrimp,
while the remaining nutrients were released into the surrounding water (Briggs
and Funge-Smith, 1994). Phosphorus releases were estimated to be 9.4 kg
(Ackefors and Enell, 1990) and 19.6–22.4 kg (Holby and Hall, 1991) per ton of
shrimp produced. This release may cause environmental and socio-economic
problems (Troell et al., 1999). The future aquaculture must be based on the
development of sustainable environmentally sounded production techniques
(Neori et al., 2004).
In recent years, integrated aquaculture has been proposed as a mean to reduce the
nutrient loading from aquaculture, including the improvement of feed utilization
by animals. Feed aquaculture (e.g. finfish, shrimp) needs to be integrated with
organic and inorganic extractive aquaculture (e.g. shellfish and seaweed). Schulz
et al. (2003) reported the total suspended solids (TSS) were reduced by 95.8-
97.3% from rainbow trout farm effluent in constructed wetland with emergent
plants and subsurface horizontal water flow. This nutrient incorporation of cocultured
organisms of different trophic levels is the basis of environmentally
sounded aquaculture (Chopin et al., 2001; Neori et al., 2004). Integrated
aquaculture provides nutrient bioremediation, mutual benefits to the co-cultured
organisms, economic diversification and increased profitability. Ideally, nutrient
process in polyculture system with two or more ecologically compatible species
should be balanced, waste from one species are recycled as fertilizer or feed by
another without conflicting with each other (Neori et al., 2000).
The aim of this paper is to present and discuss the nutrient fluxes from various
polyculture systems on coastal waters. Additionally, comparative studies in this
paper provide evidence that polyculture represents a promising technique relative
to conventional monoculture for the production of aquaculture.
Polyculture system
Polyculture is the practice of culturing more than one species of aquatic organism
in the same pond. The motivating principle is that fish production in ponds may
8

e maximized by raising a combination of species having different food habits.
The concept of polyculture of fish is based on the concept of total utilization of
different trophic and spatial niches of a pond in order to obtain maximum fish
production per unit area (Edward, 1992; Chiang, 1993; Qian et al., 1996). The
mixture of fish gives better utilization of available natural food produced in a
pond. The compatible fish species having complimentary feeding habits are
stocked so that all the ecological niches of pond ecosystem are effectively
utilized. The possibility of increasing fish production per unit area, through
polyculture, is considerable, when compared with monoculture system of fish.
Different species combination in polyculture system effectively contributes also to
improve the pond environment (Buschmann, 1996; Schuenhoff et al., 2003; Matos
et al., 2006).
Ponds that have been enriched through chemical fertilization, manuring or feeding
practices contain abundant natural fish food organisms living at different depths
and locations in the water column. Most fish feed predominantly on selected
groups of these organisms. Polyculture should combine fish having different
feeding habits in proportions that effectively utilize these various natural feed
items (Figure 1). As a result, higher yields are obtained (Bocek, unpublished).
Figure 1: Polyculture utilizes natural foods efficiently
(source: Bocek, unpublished)
9

Shrimp ponds are traditionally set up in marine coastal areas and can lead to
adverse impact on the environment, especially of large areas of mangrove forest.
Cage culture can be a more sustainable alternative for rearing shrimp and
polyculture with seaweed may also improve sustainability.
Table 1. Worldwide polyculture system
Species Location Objective References
Shrimp (Penaeus monodon)
and Milkfish (Chanos
chanos)
Abalone (Haliotis
tuberculata), fish, and
seaweed (Ulva lactuca)
Thailand To compare shrimp
performance
between mono and
polyculture system
Israel To evaluated Nbudgets
and fish
performance
Tilapia and shrimp Thailand To increase fish
production
Fish (Sparus aurata and
seaweed (Ulva. lactuca)
Shrimp (Litopenaeus
vannamei) and seaweed
(Kappaphycus alvarezii)
Portugal To evaluated the
performance of
ponds with effluent
through seaweed
Brazil To test the
feasibility of coculturing
shrimp
and seaweed
Kuntiyo and Balio,
1997
Neori et al., 1998
Yi et al., 2003
Schuenhoff et al.,
2003
Lombardi et al.,
2006
Table 1 show the worldwide various polyculture systems that have been done by
several researchers. Kuntiyo and Balio (1997) reported after 109 culture days,
results showed no significant difference (P>0.05) on growth and survival rates of
both commodities in two culture schemes. Mean weight gain was 30.88 g for
shrimp and 263.33 g for milkfish in monoculture and 31.85 g and 210.57 g for
shrimp and milkfish, respectively, in the polyculture system. Mean survival rates
10

were 94.03% for shrimp and 99.0% for milkfish in monoculture; and 82.13% for
shrimp and 92.33% for milk-fish for the polyculture system. Net aggregate
production, however, was highly significant in polyculture, attaining 923.50
kg/ha/crop. Economic feasibility revealed encouraging results for polyculture over
monoculture, with return on investment (ROI) valued at 45% for polyculture.
Nutrient flux
The two significant components of the pond environment are the pond water and
sediment which interact continuously to influence the culture environment. Pond
sediment can be further divided into the pond soil component (the pond bottom
and walls) and the accumulated sediment component (Briggs and Funge-Smith,
1994).
Nutrient budget are derived for solid, particulate organic matter, nitrogen, and
phosphorus. The erosion of pond soil is the major source of solid budget and
organic matter in the pond. The feed applied to the pond is a significant source of
organic matter (31-50%) in the pond but contributed little amount of solids (4-7%)
to the system (Funge-Smith and Briggs, 1998). This is important since the feed
component is also an indication of the faecal contribution by fish or shrimp.
Funge-Smith and Stewart (1996) reported the nitrogen budgets reveal in more
detail, the source and sinks of the organic components in an intensive shrimp pond
(Table 2). Applied feed accounted for 78% of the input N to the ponds. Erosion of
the pond soils, whilst a major contributor of solid, accounted for only 16% of
added to the system. Other minor contribution was influent water (4.03%), and
fertilizer, rainfall, shrimp stocked (2%). The sinks for nitrogen were the sediments
(24%), harvested shrimp (18%), and discharged water (28%). This leaves
approximately 30% of the nitrogen unaccounted for which is assumed to be N lost
to the atmosphere as N2.
11

Table 2. Nitrogen budget for intensive shrimp ponds (Funge-Smith and Stewart,
1996)
Source and sinks Nitrogen (%)
Nitrogen input
Feed 78
Fertilizer 1.8
Rainfall 0.12
Shrimp stocked 0.02
Influent water 4.03
Erosion of pond soil 16
Nitrogen output
Sediment removal 24
Shrimp harvest 18
Water outflow 17
Harvest drainage 11
Denitrification 30
Application of seaweed to polyculture system
The use of seaweed integrated with fish cultures has been studied in open water
and land-based system condition in Israel, Portugal, Brazil, and Indonesia (Neori
et al., 1998; Schuenhoff et al., 2003; Lombardi et al., 2006). General concepts
about nutrient uptake by seaweed can be found in Harrison and Hurd (2001). To
optimize the seaweed component of an integrated aquaculture system, particular
attention should be given not only to physical and chemical factors such as light,
temperature, effluent nutrient concentration and flux, and water motion but also
biological factors such as interplant variability, nutrient prehistory, type of plant
tissue and age.
A pilot scale system for the intensive abalone in polyculture system was
established aimed at eliminating the dependence on external feed source and
nutrient discharge levels. Effluents from abalone (Haliotis tuberculata) culture
tanks drained into seaweed (Ulva lactuca) culture and biofilter tanks. Nitrogenous
12

waste products by abalone contributed to the nutrition of seaweed. The abalone
grew on average 0.26%/d and mean seaweed production amounted 230 g/m 2 /d.
Nitrogen supplied was removed on average 58% (Neori et al., 1998).
Polyculture system consisted of fish and seaweed was evaluated by Schuenhoff et
al. (2003). An intensive fishpond (Sparus aurata) and three stage seaweed Ulva
lactuca biofilter were used which recirculated 50% of the effluent back to the
fishpond. Seaweed mean production was 94 g/m 2 /day. Nitrogen content of Ulva
lactuca was 34% of dry weight. Seaweed Ulva lactuca can remove 30% of
dissolved nutrient load from fishpond.
There were no negative interferences in co-culturing shrimp and seaweed inside
the same cage. Lombardi et al. (2006) reported no significant difference (P>0.05)
between two treatment (monoculture and polyculture with seaweed) for shrimp
weight gain, food conversion rate (FCR), and survival rate. Shrimp yield reached
production rates of 3.23 kg/m 2 /a and seaweed Kappaphycus alvarezii production
reached rates as high as 23.70 kg/m 2 /a. It means seaweed is able to grow inside
shrimp cage (Table 3).
Seaweed can also be a useful tool for measuring the zone of influence of an
aquaculture site, because they are integrators of bioavailable nutrients over time
(Troell et al., 1997). Jimenez del Rio (1994) found that increasing ammonium
loading rates per unit area of Ulva lactuca tank cultures fed with fish effluents led
to decrease dissolved nitrogen efficiency but increased nitrogen area uptake rate.
Seaweed yield and protein content also increased with increasing ammonium
supply per unit area. The same conclusion as ammonium uptake efficiency
decreased with the water turnover rate but the uptake per gram of Gracillaria per
time increased (Troell et al., 1997). Seaweed performs better as nitrogen absorber
with ammonium than with nitrate which is excellent in context on intensive fish
aquaculture where most of nitrogen is released as ammonium (Carmona et al.,
2001).
Review of result
Polyculture systems using seaweeds for the removal or conversion of wastes has
been done together with shrimp or fish. Lombardi et al. (2006) calculated the
13

mean relative growth rate (RGR) for seaweed is 0.80-1.30%/day. This value is
lower compared to the others (Table 3). The highest RGR is nearly 3.00%/day
reported by Eswaran et al. (2002). The result suggest that depth is the main factor
that affects the growth of seaweed, because in most of the experiment higher RGR
were observed on surface floating ropes, whereas the lowest RGR from Lombardi
et al. (2006) were cultured at different depth between 1 – 2 m.
Table 3. Relative growth rate (RGR) of seaweed in various studies (Lombardo et
al., 2006)
RGR (%) Condition Reference
0.80 – 1.30 Inside cages Lombardy et al., 2006
3.72 – 7.17 Inside cages Hurtado-Ponce, 1992
8.00 – 10.00 Outside cages Rincones and Rubio,
1998
4.00 – 8.00 Outside cages Ohno et al., 1999
2.30 – 4.20 Outside cages Hurtado et al., 2001
6.50 – 10.70 Outside cages De Paula et al., 2001
Nearly 3.00 Outside cages Eswaran et al., 2002
During the last decade, renewed interest in incorporating seaweed as a biofilter
link in integrated carnivore-herbivore polyculture system has produce new
approach and practical technologies (Troell et al., 1999; De Paula et al., 2002;
Eswaran et al., 2002; Lombardi et al., 2006). These studies indicate that seaweeds
especially Gracillaria sp. can assimilate as much as 5-20% of the ammonium
produced by intensive fish or shrimp culture (Lombardi et al., 2006).
The main issue in the effective implementation of polyculture systems is their
optimal functioning, which requires an in-depth understanding of the physiology
and nutrition of the selected species. With seaweed, like with many organisms, the
different physiological processes taking place have different environmental
requirements (Harrison and Hurd, 2001). Consequently, the optimization of the
overall efficiency of a cultivation system can be complex because it will require a
compromise between apparently conflicting objective e.g. biomass or particular
14

compound production versus bioremediation efficiency (Chopin and Yarish,
1998). For example, growth, nutrient uptake, carrageenan (agar production), and
phycocolloid quality respond differentially to nutrient enrichment (Buschmann et
al., 2001).
In tank culture, nutrient availability can be controlled by changing the water flow.
By increasing the water flow, nutrient flux will increase as well, which allows a
high biomass production of nutrient-sufficient seaweeds. In the other side, the
nutrient uptake efficiency is low and nutrient concentration remains high in the
effluents. If the water flow is low, nutrients become limiting and seaweed biomass
production decreases, but the nutrient uptake efficiency is higher (Hanisak, 1998).
If seaweed is only used as a biofilter and identified low commercial value species
like Ulva lactuca, they can be used to depurate fish effluents (Schuenhoff et al.,
2003). However, this apparent bioremediation merely shifts the problem of waste
disposal as the seaweed scrubber will in turn need to be disposed of or treated. On
the other hand, species like Gracilaria sp., Porphyra sp., or Laminaria sp. offer
both high bioremediation efficiency and commercial value in established market
such as human consumption (Neori and Shpigel, 1999).
When the value added for the service of improving water quality and coastal
health is finally recognized, quantified and combined with that of the principal
crop (shrimp aquaculture), the seaweed component of a polyculture system will be
understood to significantly improve the success of a diversified operation. An
accrued benefit to operators of polyculture system is the fact that the currently
discharge (unassimilated or excreted) nitrogen and phosphorus, which represent a
loss of money in real terms, will be captured and converted into the production of
salable biomass and bioproducts, hence generating revenues that may more than
compensate for the expenses. Additionally, as legislative guidelines, standards,
and controls regarding the discharge of inorganic nutrients into coastal waters
become more stringent in many countries and for sustainable aquaculture,
bioremediation via the production of seaweeds will help the shrimp aquaculture
industry and avoid noncompliance.
To successfully develop integrated aquaculture system, much research and
development remains to be undertaken, particularly in the following areas:
15

1. Transfer and modification of cultivation technologies to local environments
and socioeconomics,
2. development of the cultivation of native species of marketable value that will
be fast growing at different times of the year and in diverse habitats,
3. site-specific biological, chemical, physical, and socioeconomic modelling to
define the appropriate proportions between the different co-cultured
organisms.
Conclusions
Responsible aquaculture practices should be based on balanced ecosystem
management approach, the basic premise of which is to incorporate the biological
and environmental function of a diverse group of organisms into a unified system
that maintains the natural interaction of species and allows an ecosystem to
function sustainably. To help and to ensure its sustainability, however, it needs to
responsibly change its too often monoculture practices by adopting polyculture
ones to become better integrated into broader coastal management framework.
References
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aquaculture systems in Nordic countries. Journal Appl. Ichthyol. 10:225-
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Bergheim, A., Kristiansen, R., Kelly, L. 1993. Treatment and utilization of sludge
from landbased farms for salmon. In: Wang, J. K. (Ed.), Techniques for
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Conference, 21-23 June 1993. Washington, DC. USA. Pp 1134.
Buschmann, A.H., M. Troell, N. Kautsky and L. Kautsky. 1996. Integrated tank
cultivation of salmonids and Gracillaria chilensis. Hydrobiology,
326/327: 75-82.
Briggs, M. R. P., and Funge-Smith, S. J. 1994. A nutrient budget of some
intensive marine shrimp ponds in Thailand. Aquacult. Fisheries Manage.
25:789-811.
16

Carmona, R., Kraemer, G. P., Zertuche, J. A., Chanes, L., Chopin, T., Neefus, C.,
Yarish, C. 2001. Exploring Porphyra species for use as nitrogen scrubbers
in integrated aquaculture. Journal Phycol. 37:9-10.
Chiang, Y. M. 1993. Seaweed cultivation in Taiwan. In Liao, I. C., Cheng, J. H.,
Wu, M. C., Guo, J. J. (Eds.) Proc. Symp. On Aquaculture held in Beijing,
21-23 December 1992. Taiwan Fisheries Research Institute, Keelung, pp.
143-151
Chopin, T., A. H Buschmann, C. Halling, M Troell, N Kautsky, A. Neori, G.
Kraemer, J. Zertuche-Gonzalez, C. Yarish, C. Neefus. 2001. Integrating
seaweeds into aquaculture systems: a key towards sustainability. J Phycol
37:975–986.
Chopin, T. and Yarish, C. 1998. Nutrients or not nutrients? That is the question in
seaweed aquaculture and the answer depends on the type and purpose of
the aquaculture system. World Aquaculture, 29:31-3, 60-1.
De Paula, E. J., Pereira, R. T., Ohno, M. 2002. Growth rate of the
carrageenophyte Kappaphycus alvarezii (Rhodophyta, Gigartinales)
introduced in subtropical waters of Sao Paulo State, Brazil. Phycol. Res.
50:1-9.
Edward, P. 1992. Reuse of human wastes in aquaculture, a technical review.
Water and sanitation report no 2. UNDP-World Bank Sanitation Program.
World Bank. Washington, DC. Pp, 33-50.
Eswaran, K., Ghosh, P. K., Mairh, O. P. 2002. Experimental field cultivation of
Kappaphycus alvarezii (Doty) Doty ex. P. Silva at Mandapam region.
Seaweed Res. Util. 24: 67-72.
FAO. 2010. The state of world fisheries and aquaculture. Fisheries and
aquaculture department. Food and Agriculture Organization of United
Nations. Rome. Italy.
Funge-Smith, S. J. and Stewart, J. A. 1996. Coastal Aquaculture: Identification of
Social, Economic and Environmental Constraints to Sustainability with
Reference to Shrimp Culture. In: Coastal Aquaculture and Environment:
Strategies for Sustainability. Institute of Aquaculture, University of
Stirling. Stirling. Scotland.
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Hanisak, M. D. 1998. Seaweed cultivation: global trends. World Aquaculture,
29:18-21
Harrison, P. J., and Hurd, C. L. 2001. Nutrient physiology of seaweeds:
application of concepts to aquaculture. Cah. Biol. Mar. 42:71-82
Holby, O. and Hall, P. O. J. 1991. Chemical fluxes and mass balances in a marine
fish cage farm. II. Phosphorus. Mar. Ecol. Prog. Ser., 70: 263-272.
Jimenez del Rio, M., Ramazanov, Z., Garcia-Reina, G. 1994. Optimization of
yield and biofiltering efficiencies of Ulva rigida C. Ag. Cultivated with
Sparus aurata L. waste waters. Sci. Mar. 58:329-35
Kuntiyo and Balio.1997. Comparative study between mono and polyculture
systems on the production of prawn and milkfish in brackish water ponds.
Network of Aquaculture Centres in Asia Bangkok, Thailand.
Lombardi, J. V., de Almeida-Marques, H. L., Pereira, R. T. L., Barreto, O. J. S.,
de Paula, E. J. 2006. Cage polyculture of the Pacific white shrimp
Litopenaeus vannamei and the Philippines seaweed Kappaphycus
alvarezii. J. Aquacult. 258:412-415.
Neori, A., Ragg, N. L.C., Shpigel, M. 1998. The integrated culture of seaweed,
abalone, fish and clams in modular intensive land-based systems: II.
Performance and nitrogen partitioning within an abalone (Haliotis
tuberculata) and macroalgae culture system. Aquacult. Eng. 17:215-239.
Neori, A., M Shpigel, D. Ben-Ezra. 2000. Sustainable integrated system for
culture fish, seaweed and abalone. Aquaculture. 186. 279-291.
Neori, A., T. Chopin T, M. Troell, A. H. Buschmann, G.P. Kraemer, C. Halling,
M. Shpigel, C Yarish. 2004. Integrated aquaculture: rationale, evolution
and state of the art emphasizing seaweed biofiltration in modern
mariculture. Aquaculture 231:361–391.
Neori, A. and Shpigel, M. 2003. Using algae to treat effluents and feed
invertebrates in sustainable integrated mariculture. World Aquacult
30(2):46–51
Schuenhoff, A., Shpigel, M., Lupatsch, I., Ashkenazi, A., Msuya, F. E., Neori, A.
2003. A semi-recirculating, integrated system for the culture of fish and
seaweed. Aquaculture 221:167–181.
18

Schulz, C., J. Gelbrecht, B. Rennert. 2003. Treatment of rainbow trout farm
effluents in constructed wetland with emergent plants and subsurface
horizontal water flow. Aquaculture. Elsevier. 217: 207-221.
Troell, M., C Halling, A Nilsson, A. H Buschmann., N Kautsky, L Kautsky. 1997.
Integrated marine cultivation of Gracillaria chilensis (Gracilariales,
Bangiophyceae) and salmon cages for reduced environmental impact and
increased economic output. Aquaculture 156:45–61.
Troell, M., P. Ronnback, C. Halling, N. Kautsky and A.H. Buschmann. 1999.
Ecological engineering in aquaculture: Use of seaweeds for removing the
nutrients from the intensive mariculture. J. Appl. Phycol., 11: 89-97.
19

Chapter 2: A Comparison of Nutrients Fluxes in Monoculture and
Polyculture Systems for Shrimp (Penaeus vannamei) and
Seaweed (Gracillaria verrucosa) Production
Y. N. Ihsan ab , K. J. Hesse c , N. Holmgren d, C. Schulz ab
a Gesellschaft für Marine Aquakultur mbH, Hafentörn 3, D-25761 Büsum
b Institute for Animal Breeding and Husbandry, Christian-Albrechts-Universität
D-24098 Kiel
c Research and Technology Centre, Christian-Albrechts-Universität
D-25761 Büsum
d
University of Skövde – Sweden
541 28, Skövde – Sweden
Submitted to the Journal of World Aquaculture Society
20

Abstract
Integrated aquaculture systems are well known to utilize various forms of
nutrients with higher total assimilation rates than monoculture. In order to
evaluate the nutrient efficiency of combined shrimp and seaweed production
nutrient fluxes were compared with shrimp monoculture systems. Therefore
triplicate ponds of 1200 m² were stocked with Gracillaria verrucosa (50 kg) and
20 individuals of shrimp (0.22 ± 0.016 g/ind)/m 2 . The culture period lasted 100
days and water samples to describe nutrient fluxes were taken every 10 days. The
average ammonium-nitrogen concentration over the whole period was 0.24 mg/l
in polyculture while in monoculture 0.37 mg/l of ammonium-nitrogen were
analyzed. Survival rate of shrimp in polyculture and monoculture were 86.32%
and 69.17% respectively. A mass balance model was developed for total nitrogen
and total phosphorus to estimate their fluxes. From the total nitrogen and total
phosphorus input, 24.2% and 5.3% were incorporated in 335.7 kg/1200 m 2 shrimp
weight gain in monoculture, while 30.8% and 6.9% were incorporated in 501.5
kg/1200m 2 shrimp weight gain and 3.5% and 2.4% were incorporated in 325
kg/1200 m 2 seaweed Gracillaria in polyculture system. Therefore, polyculture
systems using seaweed Gracillaria seem to act more efficiently with regard to
nutrient accumulation.
21

Introduction
Shrimp aquaculture has been developed towards a commercial industry in
Southeast Asian countries including Indonesia. The coastal area, which includes
mangrove forests, has been changed to be utilized for aquaculture activities within
the last decades (Clough, 1993). Moreover, an effluent containing a large quantity
of nutrients as a result of feed and fertilizer application, has been discharged from
aquaculture ponds into the environment. Rapid development of intensive
aquaculture in coastal areas throughout the world has raised increasing concerns
on its environmental impact (Wu, 1995; Mazzola et al., 1999). Organic and
inorganic inputs have led to a substantial increase of nutrient loading in coastal
waters.
In general, shrimp culture produces a large amount of waste, including nitrogen
and phosphorus, that is released to the aquatic environment. Feed and fertilizer
which are applied in shrimp ponds are not fully incorporated into the shrimp, but
partly deposited in pond sediments or discharged as effluents. In average, shrimp
assimilates only 23-31% of nitrogen and 10-13% of phosphorus of the total
inputs. While remaining 14-53% of nitrogen inputs and 39-67% of phosphorus
inputs are deposited in the sediment (Dhirendra and Lin, 2002). Nutrient in
aquaculture effluents are distributed in a particulate or soluble fraction (Ackefors
and Enell, 1994). In fresh manure, about 7-32% of total nitrogen (TN) and 30-
84% of total phosphorus (TP) are bound in this particulate fraction and the
remainder are excreted in dissolved forms (Bergheim et al., 1993). In intensive
marine shrimp culture, only 24% and 13% of dietary nitrogen and phosphorus
were incorporated into harvested shrimp, while the remaining nutrients were
released into the surrounding water (Briggs and Funge-Smith, 1994). Phosphorus
releases were estimated to be 9.4 kg (Ackefors and Enell, 1990) and 19.6–22.4 kg
(Holby and Hall, 1991) per tonne of shrimp produced.
The nutrient releases during pond draining at harvest were exceeding or equaling
the limitations recommended by the U.S. Environment Protection Agency (Choo
and Tanaka, 2000). On the other hand, tidal mangrove estuaries impacted by
shrimp pond effluent, have some capacity to process intermittent inputs of pondderived
nutrients. Mangrove vegetation is capable of removing excessive
22

nutrients, of up to 70% of nutrient input for NO3 - -N and NH4 + -N, reducing PO4 2- -
P fluctuation, and producing bioactive compounds (Primavera, 2000).
In recent years, there has been increasing emphasis on developing treatment
systems for aquacultural effluents. Schulz et al. (2003) reported the total
suspended solids (TSS) were reduced by 95.8-97.3% from rainbow trout farm
effluent in constructed wetland with emergent plants and subsurface horizontal
water flow. This nutrient incorporation of co-cultured organisms of different
trophic levels is the basis of environmentally sounded aquaculture (Chopin et al.,
2001; Neori et al., 2004). Ideally, nutrient process in polyculture system with two
or more ecologically compatible species should be balanced, waste from one
species are recycled as fertilizer or feed by another without conflicting with each
other (Neori et al., 2000). By integrating fed mariculture (fish and shrimp) with
extractive mariculture (seaweed), the wastes of one resource consumer become a
source (fertilizer or feed) for others in the system. Such a balanced ecosystem
approach provides nutrient bioremediation capacity, mutual benefits to cocultured
organisms, and economic diversification by producing other value added
materials (Chopin et al., 2001).
Silvofisheries or aquasilviculture, in which low-density cultures are integrated in
mangrove areas, have been reviewed by Primavera (2000). Mangrove ecosystem
plays an obvious role in maintaining the biological balance in the coastal
environment where shrimp ponds are usually constructed. The removal of
mangroves around shrimp ponds has frequently resulted in harvest failure. Boyd
(1999) claimed that mangrove forests are not a suitable site for shrimp farms due
to many reasons such as inadequate slope for drainage, excessive organic matter
releases, nitrogen, phosphorus, acid sulphate soil or pyrite discharge. Effluent
treatment in shrimp aquaculture by macroalgae co-cultivation is still not generally
practiced. However, studies investigating the performance of integrated
mariculture (polyculture) in open-waters, have been hampered by the difficulties
involved with the experimental setup and data collection at sea (Petrell and Alie,
1996; Troell et al., 1997; Neori, 2004).
23

In this research, we aim to compare nutrient fluxes in shrimp monoculture with
shrimps and seaweed polyculture systems designed to enhance nutrient utilization
and to decrease environmental impact of aquaculture activities.
Materials and methods
This study was conducted at the Sungai Buntu research station, Research Institute
for Brackish water fisheries, West Java, Indonesia (Figure 1). Shrimp aquaculture
was intensively carried out for about 3 months from 26 September 2009 to 05
Januar 2010. The experimental site was divided into 3 divisions: Water input
(canal) approximately 1 ha, triplicate of shrimp aquaculture ponds (intensive
monoculture) and triplicate of shrimp + seaweed Gracillaria ponds (intensive
polyculture) (Figure 2). The area of each pond was 1200 m 2 (40 m x 30 m) and
the water depth of each pond was 1 m.
Location of experiments
(Sungai Buntu-West Java)
Figure 1. Map of Research Institute for Brackish water fisheries, West Java,
Indonesia
24

Ocean
(North
Java Sea)
Fresh Fresh sea Water
water input A input
Chanel
Water Stock
B B B
C C C
River
Intensive monocilture
system
Waste Waste water water output
output
Intensive polyculture
system
Sampling point:
A. Water inflow
B. Polyculture system
C. Monoculture system
: Gracilaria
Figure 2. Schematic outline of shrimp monoculture and polyculture systems
Each pond was fertilized with 3 kg of urea before stocking of shrimp and
Gracillaria. Fertilizers were used to increase primary productivity or natural food
establishment in ponds.
The seaweed Gracillaria (Gracillaria verrucosa), provided from local production
in Sungai Buntu, Karawang-West Java was inserted into polyethylene ropes that
were fixed by the rafts. A suspension culture unit was composed of four rafts,
each in turn of nine ropes. Each rope (about 10 m long) was inserted with a piece
of alga (15 g) every 20 cm. Distance between adjacent ropes was 50 cm and
between adjacent units distance was 3 m.
Shrimp Penaeus vannamei post larvae (0.22 ± 0.016 g/ind) were stocked at a
density of 20 individuals/m 2 (Table 2) in each of the 6 ponds. Triplicate
polyculture ponds of 1200 m² were additionally stocked with Gracillaria. Before
stocking, shrimp were acclimatized for one night to the pond water conditions.
Control sampling of shrimp weight gain was realized every 10 days to determine
the actual weight for feed application. 5 individuals were taken to be weighed.
Feed supplied equaled to 7-10% of shrimp biomass in accordance to time after
control sampling (modified after Baliao and Tookwinas, 2002). At day 0 and day
1 after sampling, daily feed supply amounted 7%, from day 2 until day 4 8%,
from day 5 until day 7 9% and from day 8 until day 9 10%. Feed was given 4
25

times a day, i.e. at 07.00, 12.00, 17.00 and 22.00. Two percent of the water
volume of the shrimp ponds was added every day.
Every 10 days ponds were monitored to estimate the survival rate (SR) of shrimp.
Survival rate (SR) was calculated as ratio between the numbers of shrimp at a
certain time (at sampling) to the number of shrimp at the time of stocking. To
determine the number of shrimp at sampling following formula were used:
Nt = Nu * Lt / Lj
Description:
Nt = number of shrimp in ponds at time-t
Nu = number of shrimp caught in nets at each sampling time-t
Lt = pond area (m 2 )
Lj = net effective aperture area (m 2 ).
Nutrient sampling
Every 10 days, the water quality (ammonium-nitrogen, nitrate-nitrogen, nitritenitrogen,
orthophosphate-phosphorus and hydrogen sulphide) were analysed. The
samples were taken over 24 hours by intervals of 3 hours. Water sample were
taken 20 cm below the water surface. Every day at 08.00 and 16.00, water
temperature, salinity, and dissolved oxygen (DO) were monitored in situ with a
portable water quality sensor system (TOA model WQC-20A electronic Ltd.,
Japan). Water samples were collected using plastic bottles installed at the edge of
a stick. They were immediately filtered through Whatman GF/F filters 0.7 µM
millipore for soluble nutrients analyses (PO4 -3 , NO3 - , NO2 _ , NH4 + ). The
ammonium-nitrogen concentration in the filtrate was measured immediately after
filtration. Total nitrogen (TN), total phosphorus (TP), nitrate-nitrogen, nitritenitrogen,
and orthophosphat concentrations were measured by the APHA (1995)
standard method. The nutrient analyses were performed by spectrophotometer
(Shimadzu UV-2400).
The standard methods for the determination of ammonium-, nitrite- and nitratenitrogen
were based on moderate alkaline solution with hypochlorite,
diazotization and cadmium reduction followed by diazotization, respectively. The
standard method for the determination of orthophosphat was based on the reaction
26

of the phosphorus ions with an acidified molybdate reagent. The
spectrophotometer wave length for ammonium-nitrogen, nitrite-nitrogen, nitratenitrogen
and phosphorus were 630 nm, 542 nm, 542 nm and 882 nm, respectively.
Pre-ashed (500 °C) and weight of GF/F filters in glass dishes were used to
determine suspended solids in accordance to standard filtration method
(APHA,1995). Nitrogen and phosporus content in organic matter of shrimp feed,
shrimp, Gracillaria and total suspended solids were measured using Kjehdahl
method. H2S was measured by Cline methode based on N, N-dimethyl-pphenylenediamine
(Cline, 1968).
Statistics
Water quality and nutrient fluxes from water inflow, monoculture and polyculture
ponds were analyzed statistically. All data were checked for normality
(Kolmogorov – Smirnov test) and homogeneity of variances (HOV, Brown
Forsythe test). Differences of means of triplicate ponds (n=3) were evaluated for
significance by the range tests of Tukey HSD (P

Result and discussion
Water quality
Water temperature ranged from 23.7–28.7 ºC. Average values of temperature
ranged between 26.5–27.8 o C at sampling points. Salinity also showed no
significant difference between the mono- and polyculture systems (P>0.05).
Average values of salinity for inflow water (canal), monoculture and polyculture
ponds were 36.7 ppt, 38.2 ppt and 37.7 ppt, respectively (Table 1). This values
were high as the experiments were realized during dry season. Dissolved oxygen
in water is the most important factor which determines water quality for
aquacultural purposes. Appropriate dissolved oxygen (DO) level for shrimp
aquaculture are higher than 3 mg/l. In this study, the average of dissolved oxygen
(DO) over 100 days period in monoculture was 3.03 mg/l while in polyculture
significantly higher DO values of 4.77 mg/l were recorded (Tabel 1). It can be
assumed that in day light, Gracillaria produces sufficient amounts of oxygen by
photosynthesis activities.
Table 1. Water quality parameter over 100 days period
Parameter Inflow Monoculture Polyculture
Temperature ( o C) 27.84 a 26.5±1.02 a 26.50±1.05 a
Dissolved oxygen (mg/l) 4.2 a 3.03±0.58 b 4.77±0.67 a
Salinity (ppt) 36.7 a 38.18±0.74 a 37.72±0.57 a
pH 7.75 a 7.77±0.15 a 7.73±0.17 a
TSS (mg/l)* 15.6 a 59.89±8.44 b 56.5±7.53 b
TN (mg/l)* 0.95 a 2.97±0.50 b 3.2±0.33 b
TP (mg/l)* 0.17 a 1.3±0.19 b 1.1±0.22 b
NH4 + -N (mg/l) 0.014 a 0.37±0.04 b 0.24±0.03 c
NO3 - -N (mg/l) 0.004 a 0.018±0.001 b 0.017±0.001 b
NO2 - -N (mg/l) 0.0002 a 0.002±0.0005 b 0.002±0.0004 b
PO4-P (mg/l) 0.001 a 0.005±0.0006 b 0.004±0.0008 b
Values given are means of 10 times sampling in triplicate ponds. (*TSS, TN, and TP are
means of 4 times sampling in triplicate ponds).
Values with the same superscript letter do not differ significantly (P>0.05).
28

Xu (2008) reported the Gracillaria cultivation can improve other aspects of water
quality instead of increasing DO. Its photosynthesis produces DO that promotes
decomposition of organics. Density raft culture of Gracillaria impedes the water
circulation and may decrease chemical oxygen demand (COD) in the water
column. In addition, several species of Gracillaria can produce oxygen under low
light condition, such as in rainy days and remediate anoxia (Xu et al., 2004).
Concentration (m g/l)
0.02
0.018
0.016
0.014
0.012
0.01
0.008
0.006
0.004
0.002
0
0 20 40 60 80 100 120
a
b
c
Time (days)
a
c
a
a
a
c
a
c
b
Polyculture
Monoculture
Inflow
Figure 3. Concentration of H2S during the experimental period, values are
mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05).
Hydrogen sulfide (H2S) can severely affect shrimp growth in pond. H2S is
produced by chemical reduction of organic matter that accumulates and forms a
thick layer of organic deposits at the bottom. High levels of hydrogen sulfide
would affect directly demersal or burrowing shrimps such as Peneaus monodon.
At levels of 0.1–0.2 mg/l of H2S in the water, shrimp growth will be disturbed and
die instantly at concentration higher than 4 mg/l (Law, 1988). In this study,
hydrogen sulfide (H2S) presented after 60 days. Highest hydrogen sulfide (H2S)
levels of 0.018 mg/l were recorded at harvest for the monoculture system and of
29

0.009 mg/l for the polyculture system (figure 3). This means that H2S was not
harmful for the growth of shrimp in monoculture and polyculture system.
Nutrients fluxes
Dissolved nutrient fixation is one of the core advantages of constructed wetlands
compared to standard mechanical effluent treatment (Schulz, 2003). In this study,
the ammonium concentration increased gradually in monoculture and polyculture
systems and orthophosphate concentration progressively increased as well.
Though well water was supplied to the pond, the ammonium-nitrogen
concentrations in monoculture increased from 0.005 to 0.779 mg/l (Figure 4), with
an average concentration of ammonium-nitrogen during the 100 days period of
0.37 mg/l (Table 1). In polyculture system, it increased from 0.003 to 0.483 mg/l
(Figure 4), with an average of 0.24 mg/l. Therefore, ammonium-nitrogen
concentrations were significantly higher in comparison to polyculture system
(P0.05).
30
Monoculture
Polyculture
Inflow

Concentration (mg/l)
Concentration (mg/l)
0.045
0.04
0.035
0.03
0.025
0.02
0.015
0.01
0.005
0
a
a
a
a
a
b
a b b
a
a
a
a
a
b b b
a
0 20 40 60 80 100 120
b
a
a
Time (days)
Figure 5. Concentrations of nitrate-nitrogen (NO3 + -N) during the
experimental period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05).
0.008
0.007
0.006
0.005
0.004
0.003
0.002
0.001
0
a
a
a
a
a
a
a a
a a a
a a
a
a
b
b b b b b b
a a
a
a
a
0 20 40 60 80 100 120
Time (days)
Figure 6. Concentrations of nitrite-nitrogen (NO2 + -N) during the
experimental period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05).
a
b
a
a
b
a
a
a
b
Monoculture
Polyculture
Inflow
Monoculture
polyculture
Inflow
Low values of nitrate- and nitrite-nitrogen, of 0.0044 and 0.0002 mg/l (Table 1)
were observed in the pond inlet and higher values were generated, possibly by
nitrification bacteria in the pond systems. Nevertheless, no differences could be
31

observed for nitrate and nitrite in monoculture or polyculture systems during the
experiment (P>0.05) (Figures 5 and 6). The average concentration of nitrate and
nitrite-nitrogen in the monoculture system were 0.018 and 0.002 mg/l,
respectively, and 0.017 and 0.002 mg/l in polyculture system (Table 1).
Hopkins et al. (1995) found that particulate matter and dissolved nutrients in the
outflow water increased considerably with higher water exchange rates. The
authors concluded that assimilation by phytoplankton and nitrifying bacteria
attached to detritus particles are the main processes of nitrogen removal from the
water column Hargreaves (1998) suggests that the potential for N removal from
ponds by denitrification is high.
Concentration (mg/l)
9
8
7
6
5
4
3
2
1
0
a a
b
a
b
0 20 40 60 80 100 120
a
Time (days)
a
b
a
Polyculture
Monoculture
Inflow
Figure 7. Concentrations of Total Nitrogen (TN) during the experimental
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05).
32

concentration (mg/l)
0.01
0.008
0.006
0.004
0.002
0
a
a
b
a
b
a a a a
b
b b
a
b
a
a
b b
0 20 40 60 80 100 120
a
Time (days)
a
a a
a
a a a
b
b b b
Monoculture
Polyculture
Inflow
Figure 8. Concentration of Orthophosphate (PO4) during the experimental
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05).
Concentration (mg/l)
3.5
3
a
2.5
2
a
a
1.5
a
1
0.5
0
b
a
a
b
b
-0.5 0 20 40 60
Time (days)
80 100 120
Polyculture
Monoculture
Inflow
Figure 9. Concentrations of Total Phosphorus (TP) during the experimental
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05).
33

Total nitrogen (TN) and total phosphorus (TP) concentration increased in the
outlet water of polyculture and monoculture ponds. TN in polyculture ponds
increased from 0.15-7.43 mg/l (Figure 7), with an average of 3.2 mg/l (Table 1),
while in monoculture TN ranged from 0.13–7.26 mg/l (Figure 7), with an average
of 2.97 mg/l (Table 1). TP in polyculture pond increased from 0.015–2.83 mg/l
(Figure 9), with an average of 1.1 mg/l (Table 1), while in monoculture values of
0.013–2.41 mg/l (Figure 9) and an average of 1.3 mg/l (Table 1) could be
observed, but no significant differences (P>0.05) could be observed between the
systems.
The average concentrations of orthophosphate in the inlet water, monoculture and
polyculture effluents during the 100 days period were 0.001, 0.005 and 0.004
mg/l, respectively (Table 1). There were no significant differences between
monoculture and polyculture system (P>0.05). Orthophosphate increased from
0.0012 mg/l to 0.0081 mg/l for monoculture and 0.0012 mg/l to 0.0067 mg/l for
the polyculture systems (Figure 8). It can be assumed that the initial concentration
of phosphorus was not influenced by inflowing phosphorus.
34

Table 2. Performance of experimental intensive shrimp polyculture and
monoculture system over 100 days period (n=3)
Parameter Polyculture Monoculture
Stocked larvae:
Stocking density
(Individuals/m 2 )
Total larvae (ind)
Weight (g/ind)
Total weight (kg)
20
24000
0.22 ± 0.016
5.1
20
24000
0.22 ± 0.016
5.1
Culture time (days) 100 100
At harvest:
Shrimp (ind/ m 2 )
Total shrimp
Individual weight
(g/ind)
Weight (kg/m 2 )
Total weight (kg)
16.8 a
20141 a
24.9 ± 1.8 a
0.42
501.5
13.5 b
16140 b
20.8 ± 1.05 b
0.28
335.7
Survival rate (%) 86.32 a 69.17 b
Total Feed (kg) 826.7 a 620 b
FCR 1.67 a 1.88 b
Values with the same superscript letter do not differ significantly (P>0.05).
Seventy thousand post larvae (PL) were stocked in the triplicate ponds with a
density of 20 ind/m 2 . Initial weight of individual larvae (PL) was 0.22 ± 0.016 g
resulting in a total stocking weight of approximately 5.1 kg/1200 m 2 .
Approximately 826.7 kg/ of pelleted feed was supplied for each polyculture
system pond and 620 kg for the triplicate monoculture ponds (Table 2). 501.5
kg/1200 m 2 of shrimp were harvested for the polyculture system and 335.7
kg/1200 m 2 for the monoculture system (Table 2). Feed given to the polyculture
ponds was higher compared to the monoculture shrimp due to the higher growth
performance in polyculture ponds. The average final weight of shrimp was 24.9 ±
35

1.8 g for polyculture systems with survival rates of 86.3%. For monoculture, the
weight of shrimp was 20.8 ± 1.05 g and survival rate accounted 69.17% (Table 2).
Survival rate of shrimp in polyculture was significantly higher than in
monoculture, and the weight of shrimp as well (P

Mass balance
Mass Balance calculations for nutrients are important to evaluate the efficiency of
feed nutrient utilization in order to estimate the polluting potential of pond
effluents (Tucker and Boyd, 1985; Briggs and Simon, 1994).
TN-mass balance polyculture system
Fertilization
3% (1.56 kg)
Water inflow
6.9%
(3.65 kg)
Seaweed stocked
0.04%
(0.02 kg)
Stocked shrimp
0.06%
(0.03 kg)
Shrimp feed 90%
(47.6 kg) a
Shrimp feed 90%
(47.6 kg) a
TN-mass balance monoculture system
Fertilization
3.8% (1.56 kg)
Water inflow
8.9% (3.65 kg)
Shrimp stocked

TP-mass balance polyculture system
Seaweed Stocked
0.06%
(0.006 kg)
Shrimp stocked
0.2%
(0.02 kg)
Fertilization
2% (0.2 kg)
Water inflow
6.2% (0.6)
TP-mass balance monoculture system
Fertilization
2.7% (0.2 kg)
Water inflow
7.9% (0.6 kg)
Shrimp stocked
0.3%
(0.02 kg)
Shrimp food
91.74% (8.9 kg) a
Shrimp harvest
6.9% (0.67 kg) a
Shrimp food
91.74% (8.9 kg) a
Shrimp harvest
6.9% (0.67 kg) a
Shrimp food
89.1% (6.7 kg) b
Shrimp food
89.1% (6.7 kg) b
Seaweed
harvest 2.4%
(0.23 kg)
Pond Water
Shrimp harvest
5.3% (0.4 kg) b
Shrimp harvest
5.3% (0.4 kg) b
Pond Water
Others
Associated
43.4%
(4.23 kg)
Outlet
water
47.3%
(4.6 kg) a
Outlet
water
47.3%
(4.6 kg) a
Others
Associated
42.8%
(3.22 kg)
Outlet
water
51.9%
(3.9 kg) a
Outlet
water
51.9%
(3.9 kg) a
Figure 11. Total phosphate mass balance in experimental polyculture and
monoculture systems. Values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly between mono- and
polyculture systems (P>0.05).
38

Using the strategy proposed by Funge-Smith and Briggs (1998), a mass balance
for the fate of nutrients in feed added to shrimp ponds was developed based on the
nutrient amount of feed and fertilizer added, shrimp and Gracillaria stocked,
shrimp and Gracillaria harvested, and nutrients in and out-flowing water.
Each pond was fertilized with approximately 3 kg urea/1200 m 2 before stocking.
Total nitrogen (TN) and total phosphate (TP) from fertilizer were 1.56 kg/1200 m 2
and 0.2 kg/1200 m 2 for the monoculture and polyculture system. Whereas TN and
TP from inflowing water were 3.65 kg/1200 m 2 and 0.6 kg/1200 m 2 for the
monoculture and polyculture system (Figures 10 and 11). Outlet water contained
10.4 kg/1200 m 2 and 3.9 kg/1200 m 2 of total nitrogen (TN) and total phosphorus
(TP), for the monoculture system and 11.27 kg/1200 m 2 and 4.6 kg for the
polyculture system (Figures 10 and 11).
Figure 10 and 11 showed total nitrogen and total phosphorus mass balance in
polyculture system with a growth performance of 0.42 kg shrimp m -2 and 0.3 kg
Gracillaria m -2 and a feed conversion ratio of 1.67 (shrimp: 34.5% dry matter,
9.4% N, 0.38% P; Feed: 90% dry matter) and with 0.28 kg shrimp m -2 and a feed
conversion ratio of 1.88 (shrimp: 33% dry matter, 8.9% N, 0.3% P; Feed: 90% dry
matter) in monoculture system.
In addition, monoculture system were characterised by 8.9% and 0.3% of applied
total nitrogen (TN) and total phosphorus (TP) incorporated in shrimp and 9.4%
and 0.38% in shrimps of the polyculture system. Gracillaria incorporated 3.31%
and 0.42% of total nitrogen (TN) and total phosphorus (TP) in polyculture
system. When shrimp were harvested, at least about 24.2% of the total nitrogen
(TN) and 5.3% of the total phosphorus (TP) for the monoculture system and about
34.3% (30.8% from shrimp harvest and 3.5% from seaweed harvest) of the total
nitrogen (TN) and 9.3% (6.9% from shrimp harvest and 2.4% from seaweed
harvest) of the total phosphorus (TP) for the polyculture system were removed
(Figures 10 and 11). Total nitrogen and total phosphorus in outlet water amounted
10.4 kg/1200 m 2 and 3.9 kg/1200 m 2 in the monoculture system. In the
polyculture ponds 11.27 kg/1200 m 2 and 4.6 kg/1200 m 2 of TP and TN were
recorded in outlet water (Figures 10 and 11).
39

The largest source of nitrogen originated from feed with 87.2% for the
monoculture and 90% for the polyculture system. The remaining nitrogen derived
from fertilizer and inflowing water, 3.8% and 8.9% for the monoculture and 3%
and 6.9% for the polyculture system (Figure 10). Outlet water contained 25.4% of
total nitrogen for the monoculture and 21.3% for the polyculture system (Figure
10). Denitrification, ammonium volatilization and total nitrogen in other organism
e.g. benthos and zooplankton were not directly evaluated in this study, but 50.4%
of total nitrogen input for the monoculture and 44.4% for the polyculture system
could be analyzed as unidentified losses. This loss of nitrogen was assumed to be
lost to the atmosphere as N2 via denitrification. The volatilization of nitrogen
emphasizes the significance of microbial decomposition process in ponds.
Another possibility for this loss of nitrogen could be the incorporation into other
organisms. Hopkins et al. (1993) could not account for 13 - 46% of total nitrogen
input in intensive shrimp ponds. 27.4% of the total nitrogen was unaccounted in a
semi intensive shrimp farm in North-Western Mexico explained by denitrification
and atmospheric diffusion of unionized ammonia (Paez-Osuna et al. 1997).
N-fixation by blue-green algae was not taken into account by the model, and the
significance of this contribution is unknown. In this model, the amount of nitrogen
from stocking larvae and Gracillaria were only 0.03 kg/1200 m 2 and 0.02
kg/1200 m 2 respectively.
The nitrogen mass balance reveal in detail, the source and sink of the organic
component in a shrimp pond. Funge-Smith and Briggs (1998) reported the actual
amount of nutrients assimilated into shrimp biomass is a small fraction of the total
amount applied as feed. Only 18-27% of nitrogen applied to the pond was
assimilated into shrimp, thus there is considerable wastage as nutrients are
incorporated into plankton biomass, volatilized or trapped in the sediment. The
sinks for nitrogen are the sediments (24%), harvested shrimp (18-27%) and
discharge water (27%). Approximately 30% of the nitrogen unaccounted is
assumed to be N losses to the atmosphere as N2 or ammonia.
The largest source of total phosphorus (TP) originated from feed, 89.1 % for the
monoculture and 91.74% for the polyculture system. The rest of TP derived from
fertilizer and water input were 2.7% and 7.9% for the monoculture systems and
40

2% and 6.2% for the polyculture system, respectively (Figure 11). Total
phosphorus in outlet water was 51.9% in the monoculture and 47.3% in the
polyculture system of total phosphorus input (Figure 11). That means, 51.9% of
total phosphorus input for monoculture and 47.3% of total phosphorus input for
polyculture system were discharged to the environment. TP associated in other
organisms e.g. benthos and zooplankton was not directly evaluated in this study,
but 42.8% of total phosphorus input for the monoculture and 43.4% for the
polyculture system were unaccounted. It can be assumed that this amount is lost
through consumption by other macrofauna or fixed in minerals in sediment.
The processes of denitrification, ammonia volatilization and phosphorus
adsorption by sediments serve to regulate their concentrations in the water column
(Tucker and Boyd, 1985). Boyd (1985) reported that 56% of phosphorus inputs in
freshwater catfish ponds was lost through uptake by sediments. Briggs and Funge-
Smith (1994) reported that 84% of the phosphorus was retained in the sediments
of intensive marine shrimp ponds in Thailand. Funge-Smith and Briggs (1998)
reported the principal source of phosphorus in intensive shrimp ponds was the
applied feed (51%). The 26% shortfall in inputs was assumed to be the eroded
pond bottom. Effluent water constituted 10% of TP loss in the budget and this is
mainly bound in the suspended solid fraction. Thus, trapping of the suspended
solid fraction is important to minimize its environmental impact.
Effluents from shrimp aquaculture typically were enriched in suspended solid and
nutrients. Different alternatives have been considered to mitigate or resolve the
impact of shrimp pond effluents on the water quality of adjacent coastal waters.
The use of polyculture technology, with shrimp and seaweed, have been
positively evaluated in this study. Improved pond design, construction of buffer
ponds, reduction and elimination of water exchange rates are other interesting
alternatives that could reduce the impact of shrimp pond effluents (Paez-Osuna,
2000), but for marginal areas polyculture seems to be a viable way to increase
nutrient efficiencies in shrimp aquaculture.
41

Conclusions
The seaweed Gracillaria can be cultivated in polyculture with shrimp. This
macroalgae can not only serve as an effective biofilter for shrimp ponds but also
can increase shrimp productivity. The weight and survival rate of shrimp in
polyculture systems were higher than in monoculture. The nutrients fluxes
demonstrate a high efficiency in polyculture systems than in monoculture. The
polyculture using Gracillaria as co-cultivation may thus encourage future
polyculture systems to be adopted by farmers as an environmentally friendly way
of aquaculture.
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45

Chapter 3: Nutrient Fluxes and Mass Balances in Various
Polyculture Systems Using Shrimp (Penaeus vannamei), Fish
(Oreochromis sp.) and Seaweed (Gracillaria verrucosa)
Y. N. Ihsan ab , K. J. Hesse c , C. Schulz ab
a Gesellschaft für Marine Aquakultur mbH, Hafentörn 3, D-25761 Büsum
b Institute for Animal Breeding and Husbandry, Christian-Albrechts-Universität
D-24098 Kiel
c Research and Technology Centre, Christian-Albrechts-Universität
D-25761 Büsum
Submitted to the Journal of World Aquaculture Society
46

Abstract
A comparative study on polyculture systems using various combinations of
shrimp (Penaeus vannamei), seaweed Gracillaria (Gracillaria verrucosa), and
fish (Oreochromis sp.) was conducted in order to calculate nutrients fluxes and
mass balances. Therefore, triplicate ponds of 1000 m 2 size were stocked with 0.4
kg/m 2 seaweed and 15 shrimps/m 2 (polyculture I), and triplicate ponds of size
1000 m 2 were stocked with 0.4 kg/m 2 seaweed, 15 shrimps/m 2 , and 0.25 fish/m 2
(polyculture II). Every 10 days during the 90-day culture period, pooled 24hwater
samples were taken to describe nutrient fluxes in the ponds. Water quality
in both polyculture systems were within the physiological ranges for the shrimp,
with whole period average total suspended solids (TSS) concentrations of 50.5 ±
7.6 mg/l in polyculture I, while in polyculture II TSS was 64.9 ± 4.2 mg/l. The
average total nitrogen (TN) and total phosphorus (TP) amount in polyculture I
were 2.25 ± 0.4 mg/l and 0.84 ± 0.05 mg/l, respectively, while in polyculture II
TN and TP amounted 2.66 ± 0.8 mg/l and 0.89 ± 0.05 mg/l, respectively. A mass
balance model was developed for total nitrogen and total phosphorus to estimate
their fluxes. From total nitrogen and total phosphorus input, 46.79% and 14.99%
were incorporated in 313.08 kg/1000 m 2 shrimp weight gain in polyculture system
I, while 41.47% and 13.47% were incorporated in 291.25 kg/1000m 2 shrimp
weight gain and 13.64% and 5.09% were incorporated in 40.67 kg/1000 m 2 fish
weight gain in polyculture system II. Cultivated seaweed could remove up to
10.56% of supplied TN and 9.75% of TP in polyculture I, while 10.94% of
supplied TN and 8.83% of TP were incorporated seaweed in polyculture II. TN
and TP released into environment in polyculture I amounted 17.6% and 36.23%,
respectively, and in polyculture II 20.6% and 37.41%, respectively. These results
suggest that no significant differences in shrimp performance between the two
polyculture systems could be observed, additional fish biomass production in
polyculture II proves the higher nutrient retention.
47

Introduction
In recent years the contribution of fish to global diets has reached a record of
about 17 kg per capita on average, supplying over three billion people with at
least 15 percent of their total animal derived protein intake (FAO, 2010). Marine
aquaculture has been a rapidly growing industry, increasing from about 18.6
million tons in 2006 to 20.1 million tons in 2009 and these patterns are expected
to continue up to the year 2030 due to the increasing global demand and high
market value of aquaculture products (FAO, 2010).
There are many obstacles such as diseases, environmental degradation and lack of
management that fish and shrimp farmers in Southeast Asia have to overcome
(Primavera, 1998). This means there is an urgent need to develop and disseminate
aquaculture practices in an economical yet still environmental friendly manner
(Funge-Smith and Briggs, 1998). One of the main environmental issues from open
aquaculture systems is the direct discharge of significant nutrient loads into the
environment. Resulting waste accumulation generated by the aquatic animal
farming can be divided into two categories: solid wastes consisting of non-eaten
feed, faecal material, and soluble products which include ammonia, urine,
dissolved organic matter and carbon dioxide. In aquaculture effluents, about 7-
32% of total nitrogen (TN) and 30-84% of total phosphorus (TP) and up to 27%
of total carbon are bound in the particulate fraction and the remainder can be
found in dissolved form (Bergheim et al., 1993). Nutrient in farm wastes
originating from feed supply are of greatest concern due to their role in
eutrophication processes (Persson, 1991) and discharge should be minimized as
much as possible and viable.
In shrimp aquaculture, environmental conditions in terms of both quantity and
quality have increasingly become a limiting factor so that the production has
shown a tendency to shift from area-based cultivation (extensive) towards
intensified systems (Thakur and Lin, 2003). The excretion of remaining feed
components in intensive systems will have the potential to degradate
environmental conditions for shrimp culture (Boyd, 1991; Primavera, 1994). The
degradation could cause an oxygen deficiency which in turn leads to anaerobic
conditions. In anaerobic conditions, decomposition of organic material will
48

produce toxic compounds, especially ammonia (NH3) and hydrogen sulfide (H2S)
and resulting in decreased shrimp performance (Boyd, 1991; Goddard, 1996).
One way to improve aquaculture production and reduce the negative
environmental impacts is to perform polyculture systems that involve organisms
of different trophic levels. Ideally, the nutrient fluxes in the polyculture system
should be balanced with two or more ecologically compatible species, that waste
from one species is recycled to become input (fertilizer or feed) for another
species without conflicting each other (Neori et al., 2000).
In a previous study a comparison of nutrient fluxes and mass balances between
monoculture and polyculture systems using shrimp and seaweed Gracillaria has
been investigated (Ihsan et al., submitted). Polyculture systems, using seaweed
and shrimp, act more efficiently with regard to nutrient accumulation and system
performance. However, nutrient retention is often limited by additional needed
cultivation area, especially if plants are utilized (Buschmann et al., 2001). Thus,
polyculture systems using shrimp and seaweed in combination with omnivorous
tilapia proposed as a technological alternative for integrated aquaculture. At
present, this study focus on the calculation of nutrients fluxes and mass balances
in various polyculture systems using shrimp, seaweed and fish in order to identify
most efficient polyculture practices.
Material and method
The experiment was conducted in Sungai Buntu, West Java over a 90-day period
from July–October 2010 during the dry season. This area is located on the
northern Java Island (Figure 1). The experimental site was divided into 3 sectors:
Water input unit of approximately 1 ha, triplicate polyculture I systems consisting
of ponds stocked with shrimp and seaweed and triplicate polyculture II systems
consisting of shrimp + fish + seaweed ponds (Figure 2). The area of each pond
was 1000 m 2 (40 m x 25 m). The water depth of each pond amounted 1 m. Each
pond was fertilized with 3 kg/1000 m 2 of urea before stocking. Fertilizers were
used to activate and increase primary production and establishment of natural
feeds in ponds.
49

Location of experiments
(Sungai Buntu-West Java)
Figure 1. Map of Research Institute for Brackish water fisheries, West Java,
Indonesia
Figure 2. Schematic outline of polyculture systems I and II
50

The seaweed, provided from local production in Sungai Buntu, Karawang, West
Java was inserted into polyethylene ropes that were fixed by rafts. A suspension
culture unit was composed of four rafts, with each in turn consisted of nine ropes.
Each rope (about 8.5 m long) was inserted with a piece of algae (25 g) every 20
cm. The distance between adjacent ropes and units was 20 cm 3 m, respectively.
Shrimp post larvae (0.43 ± 0.11 g) were stocked in each of the 6 ponds at a density
of 15 individuals/m 2 and seaweed at a density of 0.4 kg/m 2 (Table 2). Triplicate
polyculture II ponds of 1000 m² were additionally stocked with fish (4.7 ± 0.6
g/ind) at a density of 0.25 individuals/m 2 . Before stocking, shrimp and fish were
acclimatized for one night to the pond-water conditions.
Commercial shrimp feed (Luxindo 39, Luxindo Internusa Ltd.) containing 40%
protein was given. Control sampling of shrimp weight gain was done every 10
days to determine the actual weight for feed application. For this procedure 5
individuals were caught and analyzed. Daily feed supply equaled to 7-10% of
shrimp biomass in accordance to time after control sampling (modified after
Baliao and Tookwinas, 2002). At day 0 and day 1 after sampling, daily feed
supply amounted 7%/shrimp biomass, from day 2 until day 4 8%, from day 5 until
day 7 9% and from day 8 until day 9 10% shrimp biomass were fed. Feed was
given 4 times a day, i.e. at 07.00, 12.00, 17.00 and 22.00. Two percent of the
water volume of the shrimp ponds was exchanged every day.
Sampling and analytical procedures
Fluxes of following water quality parameters were measured: temperature,
salinity, dissolved oxygen (DO), pH, alkalinity, hydrogen sulphide (H2S), total
suspended solids (TSS), ammonium, nitrate, nitrite, orthophosphate, total nitrogen
(TN) and total phosphorus (TP).
Every 10 days, the water quality was analyzed. Samples of each pond sampling
point were taken over 24 hours at 3-hour intervals and pooled for following
analytical procedures. Water sample were taken 20 cm below the water surface in
central pond inlet and each pond outlet. Every day at 08.00 and 16.00, the water
temperature, salinity, and dissolved oxygen (DO) were monitored in situ using a
portable (TOA model WQC-20A Electronic Ltd., Japan) water-quality analyzer.
51

Water samples were collected using plastic bottles attached to the end of a stick.
They were immediately filtered through Whatman GF/F filters 0.7 µM millipore
for soluble nutrients analyses (PO4 -3 , NO3 - , NO2 _ , NH4 + ). The ammonium
concentration in the filtrate was measured immediately after filtration. Total
nitrogen (TN), total phosphorus (TP), nitrate, nitrite, and orthophosphate
concentrations were measured using the APHA (1995) standard methods. The
nutrient analyses were performed with a spectrophotometer (Shimadzu UV-2400).
The standard method for determining ammonium, nitrite and nitrate were based
on moderate alkaline solution with hypochlorite, diazotization, and cadmium
reduction followed by diazotization, respectively. The standard method for
determination of phosphorus in the water and feed and shrimp, seaweed or fish
samples was based on the reaction of ions with an acidified molybdate reagent.
The spectrophotometer wave lengths for ammonium, nitrite, nitrate and
phosphorus were 630 nm, 542 nm, 542 nm, and 882 nm, respectively. GF/F filters
in glass dishes were used to determine suspended solids. Total suspended solids
were estimated using the standard filtration method (APHA, 1995). H2S was
measured using the Cline-method based on N, N-dimethyl-p-phenylenediamine
(Cline, 1968). The spectrophotometer wave length for H2S was 670 nm. Nitrogen
content in the feed, shrimp, fish and seaweed were using Kjeldahl method.
Calculation
The growth performance criteria of shrimp and fish including survival rate,
specific growth rate, and feed conversion ratio were calculated at the end of the
experiment.
Survival Rate (SR) was calculated as a ratio between the shrimp or fish quantity at
sampling times and stocking time using the formula:
SR = (Nt / N0) X 100%
With: SR = survival rate
N0 = number of shrimp or fish on day 0 (individual)
Nt = number of shrimp or fish on day t (individual)
52

Specific growth rate of shrimp or fish (SGR) represents the relative increase in
daily weight during a certain time interval and were calculated with:
SGR = ((ln Wt - ln W0) / t) X 100%
With: SGR = Specific growth rate
W 0 = weight of shrimp or fish on day-0 (g)
Wt = weight of shrimp or fish on day-t (g)
t = time of experiment (day)
Feed conversion ratio (FCR) is the ratio between the amount of feed given to
shrimp weight gain in a certain period (NRC, 1977) using the formula:
FCR = F / ΔB
With: FCR = feed conversion ratio
F = amount of feed given during experiment (kg)
ΔB = shrimp biomass weight gain during experiment (kg)
Statistics
Water quality and nutrient fluxes and growth performance parameter observed
between polyculture I and polyculture II ponds were analyzed statistically. All
data were checked for normality (Kolmogorov-Smirnov test) and homogeneity of
variances (HOV, Brown-Forsythe test). Differences of means of triplicate ponds
(n=3) were evaluated for significance using the range tests of Tukey HSD
(P

FC : Content of N or P in dry pellet
fC : Content of N or P in fertilizer
IC : Content of N or P in inflowing water
SSC : Content of N or P in stocked shrimp
SGC : Content of N or P in stocked Gracillaria
SFC : Content of N or P in stocked fish
HSC : Content of N or P in harvested shrimp
HGC : Content of N or P in harvested Gracillaria
HFC : Content of N or P in harvested fish
OC : Content of N or P in outflowing water
Result
Water quality
Table 1 shows that the average concentration of DO in polyculture systems I and
II as well as of inflowing water was in high ranges of more than 4 mg/l. The
average concentration of DO between the polyculture systems during the 90-day
experiment was not significantly different (P>0.05).
Table 1. Mean of water quality parameter over 90 days period (n=3)
Parameter Unit Water input Polyculture I Polyculture II
DO mg/l 4.5 b 5.9 ± 0.7 a 5.4 ± 0.6 a
Salinity Ppt 27.7 a 29.3 ± 1.0 a 29.9 ± 0.8 a
Température
0 C 27.8 a 26.4 ± 0.05 a 26.9 ± 0.07 a
pH - 7.9 a 8.1 ± 0.1 a 7.9 ± 0.2 a
Alkalinity mg/l 117.6 a 116.4 ± 3.2 a 112.1 ± 2.0 a
H2S mg/l 0 a 0.02 ± 0.001 a 0.03 ± 0.008 a
TSS mg/l 16.3 c 50.5 ± 7.6 a 64.9 ± 4.2 b
Values with the same superscript letter do not differ significantly (P>0.05)
54

Table 1 shows that the average salinity for the 90-day experiment was 29.30 ±
1.00 ppt for polyculture I and 29.90 ± 0.80 ppt for polyculture II. Average salinity
was not significantly different between the ponds (P>0.05).
Figure 3 shows a tendency of alkalinity to decrease during the 90-day experiment.
However, the alkalinity was not significantly different between ponds (P>0.05).
Alkalinity in polyculture I ranged between 118.93–109.33 mg/l (Figure 3) with an
average of 116.40 ± 3.20 mg/l (Table 1), while in polyculture II it ranged between
124.80–102.07 mg/l (Figure 3) with an average of 112.10 ± 2.00 mg/l (Table 1).
The average pH over the 90-day experiment was not significantly different
between polyculture I and II (P>0.05), with 8.10 ± 0.10 for polyculture I and 7.90
± 0.20 for polyculture II (Table 1).
Concentration (mg/l)
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00
Alkalinity
a a a a a
a
a a a
a
a a a a a
0 20 40 60 80 100
Time (days)
a a a
ab
b
ab
b
ab
b
Polyculture I
Polyculture II
water input
Figure 3. Concentration of Alkalinity during the experimental period, values
are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
55

Concentration (m g/l)
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00
Total Suspended Solid
a
a
b
b
b
b
a a b
a
a
a
a
c c c c c c c
0 20 40 60 80 100
a
Time (days)
Figure 4. Concentration of total suspended solid (TSS) during the
experimental period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
a
a
a
Polyculture I
Polyculture II
water input
TSS tend to increase and was significantly different between polyculture I and II
(P0.05). The average survival rate of shrimp in polyculture I during the
production period was 84.4%, while in polyculture II it was 82.8% (Table 2.). The
data showed that mortality rates were low in both systems. Survival rate of fish in
polyculture II at harvest amounted 78.8% (Table 2).
56

Table 2. Performance of experimental polyculture system over 90 days period
(n=3)
Parameter Polyculture I Polyculture II
Stocking density:
Shrimp (individual/m2)
Fish (individual/m2)
Total larvae stocked:
Shrimp (ind)
Fish (ind)
Weight of stocked larvae:
Shrimp (g/ind)
Fish (g/ind)
Total weight:
Shrimp (kg)
Fish (kg)
15
-
15000
-
0.43 ± 0.11 a
-
6.45 a
-
15
0.25
15000
250
0.43 ± 0.11 a
4.7 ± 0.6
6.45 a
1.18
Area (m2) 1000 1000
Culture time (days) 90 90
Total Feed (kg) 526.65 a 526.65 a
At harvest:
Shrimp (ind/m2)
Fish (ind/m2)
Weight:
Shrimp (g/ind)
Fish (g/ind)
Total weight:
Shrimp (kg/1000 m 2 )
Fish (kg/1000 m 2 )
12.66 a
-
24.73 ± 0.71 a
-
313.08 a
-
12.42 a
0.20
23.45 ± 1.43 a
206.1 ± 11.36
291.25 a
40.67
Survival rate
Shrimp (%)
84.4
Fish (%)
a
82.8 a
78.8
FCR 1.72 a 1.84 a
57

SGR:
Shrimp (%/day)
Fish (%/day)
4.5 a
4.4 a
4.2 a
Values with the same superscript letter do not differ significantly (P>0.05)
Figure 5 shows that the growth rate of shrimp was not significantly different
between polyculture I and II (P>0.05). The average weight of shrimp at harvest
was 24.73 ± 0.71 and 23.45 ± 1.43 g/ind for polyculture I and II, respectively
(Table 2), while the average fish weight at the time of harvest was 206.1 ± 11.36
g/ind (Table 2). Specific growth rate (SGR) for shrimp in polyculture I and II was
not significantly different (P>0.05) with an average value over the 90-day
experiment of 4.5%/day and 4.4%/day, respectively. SGR of fish over the 90-day
period amounted 4.2% /day.
Weight (g)
30.00
25.00
20.00
15.00
10.00
5.00
0.00
Weight
a
a
a
a
a
a
a
a
a
0 20 40 60 80 100
a
Time (days)
a
a
a
a
a
a
Polyculture I
Polyculture II
Figure 5. Individual weight of shrimp during the experimental period, values
are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
58

Biomass production of shrimp in polyculture I and II was not significantly
different (P>0.05) with an average value of 313.08 and 291.25 kg/1000 m 2 ,
respectively (Table 2). In polyculture II there was an additional production from
the fish of 40.67 kg/1000 m 2 (Table 2).
Nutrient flux
The ammonium concentration increased gradually in both polyculture systems
and orthophosphate concentration increased progressively as well. Even though
well water was supplied to the pond at a renewal rate of 2%/day, the ammonium
concentrations in polyculture I increased during the production period from 0.12
to 0.53 mg/l (Figure 6), with an average concentration of 0.34 ± 0.06 mg/l (Table
3). In the polyculture II system, it increased from 0.17 to 0.71 mg/l (Figure 6),
with an average over the production period of 0.45 ± 0.07 mg/l. Therefore,
ammonium concentrations in both polyculture systems did not display significant
differences (P>0.05).
Concentration (mg/l)
0.800
0.700
0.600
0.500
0.400
0.300
0.200
0.100
0.000
a
a
a b
a
c c c c
a a a a
Ammonium
a a b
c
0 20 40 60 80 100
Time (days)
a
b
a
b
c c c c
Figure 6. Concentration of ammonium-nitrogen (NH4 - -N) during the
experimental period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
59
a
a
Polyculture I
Polyculture II
Water input

Concentration (mg/l)
0.080
0.070
0.060
0.050
0.040
0.030
0.020
0.010
0.000
a
a
a a
c c
a
a
a
c c
Orthophosphate
b
a
c c c c c
0 20 40 60 80 100
b
a
Time (days)
b
a
b
a
b
a
b
Polyculture I
Polyculture II
Water input
Figure 7. Concentration of orthophosphate (PO4-P) during the experimental
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
Orthophosphate in polyculture I increased during the 90-day period from 0.01 to
0.05 mg/l (Figure 7), with an average concentration of orthophosphate of 0.03 ±
0.006 mg/l (Table 3), while in polyculture II it increased from 0.01 to 0.07 mg/l
(Figure 7) with an average of 0.04 ± 0.003 mg/l. These concentrations in both
polyculture systems did not exhibit significant differences (P>0.05).
Nitrite (NO2 - ) and nitrate (NO3 - ) in both polyculture systems did not show
significant differences (P>0.05) with average concentrations of 0.005 ± 0.001
mg/l and 0.05 ± 0.01, mg/l in polyculture I and 0.006 ± 0.001 mg/l and 0.05 ±
0.007 mg/l in polyculture II, respectively (Table 3).
60

Table 3. Mean of nutrient concentrations over 90 days period (n=3)
Variable Unit Water input Polyculture I Polyculture II
NH4 mg/l 0.014 b 0.34 ± 0.06 a 0.45 ± 0.07 a
NO2 mg/l 0.0002 b 0.005 ± 0.001 a 0.006 ± 0.001 a
NO3 mg/l 0.004 b 0.05 ± 0.01 a 0.05 ± 0.007 a
PO4 mg/l 0.01 b 0.03 ± 0.006 a 0.04 ± 0.003 a
TN mg/l 0.18 b 2.25 ± 0.4 a 2.66 ± 0.8 a
TP mg/l 0.046 b 0.84 ± 0.05 a 0.89 ± 0.05 a
Values with the same superscript letter do not differ significantly (P>0.05)
Additionally, total nitrogen (TN) and total phosphorus (TP) concentration
increased in the outlet water of polyculture systems I and II. TN in the polyculture
I pond increased from 0.40–5.15 mg/l (Figure 8), with an average of 2.25 ± 0.40
mg/l (Table 3) and TN in polyculture II ranged from 0.47–6.16 mg/l (Figure 8),
with an average of 2.66 ± 0.80 mg/l (Table 3). TP in polyculture I increased from
0.03–1.56 mg/l (Figure 9), with an average of 0.84 ± 0.05 mg/l (Table 3), while in
polyculture II values of 0.03–1.64 mg/l (Figure 9) and an average of 0.89 ± 0.05
mg/l (Table 3) could be observed, but no significant differences (P>0.05) could be
calculated between the systems.
61

Concentration (m g/l)
Concentration (mg/l)
8.000
7.000
6.000
5.000
4.000
3.000
2.000
1.000
0.000
Total Nitrogen (TN)
a
b a
a
a
b
a
b a
a
a
b
a
b
a
b
a
0 20 40 60 80 100
a
Time (days)
a
a
a a
a
b b b
a
Polyculture I
Polyculture II
Water input
Figure 8. Concentration of total nitrogen (TN) during the experimental
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
1.800
1.600
1.400
1.200
1.000
0.800
0.600
0.400
0.200
0.000
Total Phosphorus (TP)
a
a
a
a
a
a
a
a
a
a
a
a
a
a
b
a
b b b b b b b
0 20 40 60 80 100
Time (days)
a
Polyculture I
Polyculture II
water input
Figure 9. Concentration of total phosphorus (TP) during the experimental
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
62

Mass balance
Total nitrogen (TN) and total phosphorus (TP) from fertilizer amounted 1.56
kg/1000 m 2 and 0.2 kg/1000 m 2 for polyculture system I and II, respectively.
Whereas TN and TP from inflowing water were 0.5 kg/1000 m 2 and 0.13 kg/1000
m 2 for both polyculture systems (Figure 10 and 11).
TN-mass balance polyculture system I
Figure 11. Total nitrogen mass balance in experimental polyculture and
Valueare mean of triplicate ponds (n=3)
Fertilization
4.36% Values (1.56 kg) with the same superscript letter do not differ Pond significantly Water between
polyculture systems I and II (P>0.05).
a
06%
(0.02 kg) a
ssociated
25.06%
(8.97 kg) a
0.
a
Fertilization
4.36% (1.56 kg) Pond Water
a
06%
(0.02 kg) a
ssociated
25.06%
(8.97 kg) a
0.
a
Water inflow
1.4%
(0.5 kg) a
Water inflow
1.4%
(0.5 kg) a
Seaweed stocked
0.06%
(0.02 kg)
rimp stocked
a
Seaweed stocked
0.06%
(0.02 kg)
Shrimp
stocked
a
Sh
Shrimp feed
94.13%
(33.7 kg) a
Shrimp feed
94.13%
(33.7 kg) a
TN-mass balance polyculture system II
Fertilization
4.34% (1.56 kg) a
Seaweed stocked
0.06%
(0.02 kg)
Shrimp stocked
0.06%
(0.02 kg)
a
Fish stocked
0.36%
(0.13 kg)
Shrimp
0.06%
(0.02 kg) a
Fish stocked
0.36%
(0.13 kg) b
Fertilization
4.34% (1.56 kg) a
Seaweed stocked
0.06%
(0.02 kg)
Shrimp stocked
0.06%
(0.02 kg)
a
Fish stocked
0.36%
(0.13 kg)
Shrimp
0.06%
(0.02 kg) a
Fish stocked
0.36%
(0.13 kg) b
Shrimp feed
93.79% (33.7 kg) a
Shrimp feed
93.79% (33.7 kg) a
Shrimp harvest
46.79% (16.75 kg) a
Shrimp harvest
46.79% (16.75 kg) a
Shrimp harvest
41.47% (14.9 kg) a
Shrimp harvest
41.47% (14.9 kg) a
Seaweed harvest
10.56% (3.78 kg) a
Seaweed harvest
10.56% (3.78 kg) a
Seaweed harvest
10.94% (3.93 kg) a
Seaweed harvest
10.94% (3.93 kg) a
Pond Water
Others
Outlet water
17.6%
(6.3 kg) a
Outlet water
17.6%
(6.3 kg) a
Fish harvest
13.64%
(4.9 kg) b
Fish harvest
13.64%
(4.9 kg) b
Others
associated
13.36%
(4.8 kg) b
Others
associated
13.36%
(4.8 kg) b
Outlet
water
20.6%
(7.4 kg) a
Outlet
water
20.6%
(7.4 kg) a
Figure 10. Total nitrogen mass balance in experimental polyculture systems
I and II. Values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly between polyculture
systems I and II (P>0.05).
63

TP-mass balance polyculture system I
Shrimp stocked
0.15%
(0.01 kg) a
Seaweed Stocked
0.15%
(0.01 kg) a
Shrimp stocked
0.15%
(0.01 kg) a
Seaweed Stocked
0.15%
(0.01 kg) a
Fertilization
3% (0.2 kg) a
Fertilization
3% (0.2 kg) a
Water inflow
1.95% (0.13 kg) a
Water inflow
1.95% (0.13 kg) a
Shrimp feed
94.75% (6.32 kg) a
Shrimp feed
94.75% (6.32 kg) a
TP-mass balance polyculture system II
Stocked shrimp
0.15%
(0.01 kg) a
Seaweed stocked
0.15%
(0.01 kg) a
Fish stocked
0.18%
(0.012 kg) b
Stocked shrimp
0.15%
(0.01 kg) a
Seaweed stocked
0.15%
(0.01 kg) a
Fish stocked
0.18%
(0.012 kg) b
Fertilization
2.99% (0.2 kg) a
Fertilization
2.99% (0.2 kg) a
Water inflow
1.95%
(0.13 kg) a
Water inflow
1.95%
(0.13 kg) a
Shrimp feed 94.58%
(6.32 kg) a
Shrimp feed 94.58%
(6.32 kg) a
Shrimp harvest
14.99% (1.0 kg) a
Shrimp harvest
14.99% (1.0 kg) a
Shrimp harvest
13.47% (0.90 kg) a
Shrimp harvest
13.47% (0.90 kg) a
Seaweed harvest
9.75% (0.65 kg) a
Seaweed harvest
9.75% (0.65 kg) a
Pond Water
Seaweed harvest
8.83% (0.59 kg) a
Seaweed harvest
8.83% (0.59 kg) a
Pond Water
Others
Associated
40.03%
(2.67 kg) a
Others
Associated
40.03%
(2.67 kg) a
Outlet
water
35.23%
(2.35 kg) a
Outlet
water
35.23%
(2.35 kg) a
Fish harvest
5.09%
(0.34 kg) b
Fish harvest
5.09%
(0.34 kg) b
Others
associated
35.20%
(2.35 kg) b
Others
associated
35.20%
(2.35 kg) b
Outlet
water
37.41%
(2.50 kg) a
Outlet
water
37.41%
(2.50 kg) a
Figure 11. Total phosphate mass balance in experimental polyculture
systems I and II. Values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly between polyculture
systems I and II (P>0.05).
In polyculture system I shrimp yielded a growth performance of 0.31 kg/m 2 and a
feed conversion ratio (FCR) of 1.72, and in polyculture system II equal
performance with 0.29 kg/m 2 but additional 0.04 kg fish/m 2 , at FCR of 1.84.
64

Shrimp and seaweed harvested in polyculture system I incorporated in total at
least 57.35% of TN and 24.74% of TP and in polyculture system II higher but no
significantly different (P>0.05) nutrient assimilation of 66.05% for TN and of
27.39% for TP could be found in the total biomass (shrimp, seaweed and fish).
Total nitrogen and phosphorous released with the outlet water amounted 6.3
kg/1000 m 2 and 2.35 kg/1000 m 2 in polyculture system I. In the polyculture
system II, 7.4 kg/1000 m 2 and 2.50 kg/1000 m 2 of TN and TP could be found in
the outflowing water, but no significant differences (P>0.05) could be calculated
between the systems.
The largest source of TN originated from feed with 94.13% for the polyculture
system I and 93.79% for the polyculture system II. The remaining nitrogen
derived from fertilizer and inflowing water with 4.36% and 1.4% in polyculture
system I and with 4.34% and 1.39% in polyculture system II (Figure 10). In this
model, the amount of TN from stocked shrimp larvae and seaweed in polyculture
system I was 0.02 kg/1000 m 2 and 0.02 kg/1000 m 2 , respectively. This means
only 0.12% of TN in the ponds derived from stocked biomass in polyculture
system I. In polyculture system II 0.06% and 0.36 % of TN derived from stocked
seaweed and fish (Figure 10).
Outlet water contained 17.6% of TN for the polyculture system I and 20.6% for
the polyculture system II (Figure 10). 25.06% of TN in polyculture system I could
be analyzed as unidentified losses and 13.36% in polyculture system II.
With 94.75% for the polyculture system I and 94.58% for the polyculture system
II largest source of total phosphorus (TP) originated from feed, but without
significant differences (P>0.05) between the systems. The remaining TP derived
from fertilizer and inflowing water with around 3% and 1.95% for both
polyculture systems. TP originated from stocked shrimp larvae and seaweed were
0.15% and 0.15% for both polyculture systems. TP from stocked fish amounted
0.18% in polyculture system II. Total phosphorus (TP) in outlet water was 2.35
kg/1000m² for the polyculture system I and 2.50 kg/1000m² for the polyculture
system II (Figure 11). That means, 35.23% of TP input for the polyculture system
I and 37.41% of TP for the polyculture system II were discharged to the
environment, but no significant differences (P>0.05) could be calculated between
65

the systems. 40.03% and 35.20% of TP in polyculture system I and II were
unaccounted and significant differences (P0.05). It can
be stated that the utilization of feed by shrimp in polyculture I and II was efficient
for growth performance. In comparison to the global average shrimp feed
conversion ratio of around 2.0 (Tacon, 2002), the observed feed conversions in
both polyculture systems were very efficient.
In general, the presence of fish led to lower dissolved oxygen (DO) in polyculture
II than in polyculture I even though it was not significantly different (P>0.05)
(Table 1). In both polyculture systems, aeration was used every night from 22.00
until 05.00. Hydrogen sulphide (H2S) concentration for 90 days was still within
the limits. The average of H2S for polyculture I and II were 0.02 ± 0.001 and 0.03
± 0.008 mg/l (Table 1), respectively. At levels of 0.1–0.2 mg/l H2S in the water,
shrimp growth will be influenced and they will die instantly at concentrations
66

higher than 4 mg/l (Law, 1988). Thus, DO concentration and H2S for the 90-day
period were still within the safe limits for shrimp and fish. Additionally DO
concentrations should be linked with seaweed assimilation activities. Its
photosynthesis produces DO that promotes decomposition of organics (Xu, 2008).
The fish in studied polyculture system impacted the amount of suspended solids
by faecal excretion and bioturbation, so that amount of total suspended solids
(TSS) in polyculture II was higher than in polyculture I (P

study showed that seaweed can remove 3.5% of inflowing TN and 2.4% of
inflowing TP (Ihsan et al., submitted). In addition, ammonium in polyculture was
lower than in monoculture systems and amounted 0.24 mg/l while in monoculture
0.37 mg/l could be analyzed. Troell et al. (1997) reported that seaweed have a
high capacity for removing nutrients from fish effluents, and seaweed production
is higher in areas surrounding fish cage than in areas apart from aquaculture
systems. Seaweed had the potential to remove at least 5% of dissolved nitrogen
released from the fish farm and 7% of released dissolved phosphorous.
Buschmann et al. (1994) found that tank cultivated Gracillaria could remove as
much as 90-95% of the ammonium in effluent waters released from salmon tanks.
In this study, nutrient assimilation by seaweed between the two polyculture
systems did not result in significant differences (Figures 10 and 11). Our results
showed a high capacity in assimilation of excretory products from shrimp
nutrients by seaweed in both polyculture systems. The ability of Gracillaria to
assimilate and store nitrogen for ubsequent growth makes it possible to utilize
high nutrient concentrations most efficiently. Such rapid accumulation by
seaweed has been documented to function even in darkness (Cohen and Neori,
1991)
Mass balance model calculated in this study demonstrate nutrient utilization in the
evaluated polyculture systems. TN and TP incorporated in shrimp and seaweed in
polyculture I was lower than polyculture systems II but not significantly different
(Figures 10 and 11). Nutrients were efficiently utilized by shrimp, seaweed and
fish. In comparison to previous results 34.3% of TN and 9.3% of TP were
incorporated in shrimp and Gracillaria of polyculture systems while in
monoculture only 24.2% of TN and 5.3% of TP were retained in shrimp (Ihsan et
al., submitted). Neori et al. (1998) reported that the seaweed harvest contained
about 33% of the total N input and 50% was fed to the animal in the overall N
budget of the abalone tanks and their seaweed biofilter tanks. Lombardi et al.
(2006) reported that shrimp harvesting accounted for 35.5% and 6.1% of the total
nitrogen and total phosphorus input into the ponds in cage polyculture of white
shrimp with seaweed Kappaphycus alvarezii.
68

TN and TP incorporated in organism in polyculture system I were higher than in
polyculture system II, while TN and TP discharged to the environment through
outlet water in both polyculture systems did not differ significantly (Figure 10 and
11). Previous results (Ihsan et al., submitted) reported that 44.4% of TN and of
43.3% TP in polyculture systems and 50.4% of TN and 42.8% of TP in
monoculture systems were incorporated in organic biomass, whereas 21.3% and
47.3% of TN and TP were released into the environment in polyculture system in
contrast to 25.4% and 51.9% TN and TP released from monoculture systems,
respectively. Lombardi et al. (2006) reported that outlet water removed significant
quantities of nitrogen (36.7%) and phosphorus (30.3%) in cage polyculture of the
white shrimp and seaweed Kappaphycus alvarezii. Neori and Shpigel (1999)
recorded a reduction in the effluent of 72% of total nitrogen and 61% of total
phosphorus in integrated culture of prawn (Penaeus monodon), mussel (Mytilus
edulis) and seaweed Gracillaria. In polyculture system, TN and other excess
nutrients from the feed based shrimp culture are taken up by seaweed (Martinez-
Aragon et al., 2002). A primary role of biofiltration is the treatment and
conversion of toxic metabolites and pollutants. Microalgae photosynthetically
convert the dissolved inorganic nutrients into particulate matter suspended in the
water, while seaweed in contrast extract the nutrients out of the water (Troell and
Norberg, 1998). Seaweed efficiently take up dissolved inorganic nitrogen present
in fish net pen effluents (Troell et al., 1999). Seaweed growth on polyculture
effluents has been also shown to be superior than in fertilizer enriched seawater
(Neori et al., 1991).
Total nitrogen (TN) and total phosphorus (TP) incorporated in shrimp in this
study did not show significant differences (P>0.05). From the above it can be
stated that the rate of feed utilization by shrimp was optimal, as well as the ability
of seaweed Gracillaria and fish to utilize nutrients in the pond. This proves the
use of polyculture in aquaculture systems in order to improve nutrient utilization
and to decrease nutrient discharge to the environment. However, despite this
relative success, it is necessary to examine other polyculture systems by
integration of other species such as oysters with seaweed, shrimp and fish to
enhance the systems nutrient assimilation performance.
69

Conclusion
This study showed that polyculture with shrimp (Penaeus vannamei), fish (Tilapia
sp), and seaweed Gracillaria can be used to increase biomass production.
Inflowing nutrients can be used either by shrimp (Penaeus vannamei), fish
(Tilapia sp) or seaweed Gracillaria (Gracillaria verrucosa). The ability of
seaweed Gracillaria to do photosynthesis caused optimal levels of dissolved
oxygen (DO). The impact of fish as a co-culture organism caused higher total
suspended solids (TSS) in polyculture II than in polyculture I, but it was still
within the safe limits for shrimp.
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Buschmann, A.H., M. Troell, N. Kautsky and L. Kautsky. 1996. Integrated tank
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73

Chapter 4: Nitrogen Assimilation Potential of Seaweed
(Gracillaria verrucosa) in Polyculture with Pacific White Shrimps
(Penaeus vannamei)
Y. N. Ihsan ab , K. J. Hesse c , C. Schulz ab
a Gesellschaft für Marine Aquakultur mbH, Hafentörn 3, D-25761 Büsum
b Institute for Animal Breeding and Husbandry, Christian-Albrechts-Universität
D-24098 Kiel
c Research and Technology Centre, Christian-Albrechts-Universität
D-25761 Büsum
Submitted to the Journal of Asian Fisheries Society
74

Abstract
In order to evaluate the nutrient absorption efficiency of combined shrimp and
seaweed production, nitrogen fluxes in polycultures were compared with shrimp
monoculture systems. Therefore, triplicate concrete tanks, with a volume of 3 m 3 ,
were stocked with shrimp Penaeus vannamei (6–7 g, 5 ind/100 litres) and
seaweed (Gracillaria verrucosa) in densities of 0 g/l, 3.125 g/l, 6.250 g/l, and
9.375 g/l. The culture period lasted four weeks and water samples were taken
every week to measure nutrient fluxes. The use of seaweed at a density of 3.125
g/l in shrimp polyculture showed the highest ability for nitrogen assimilation
originating from shrimp waste. This treatment increased shrimp survival rate from
63% (without seaweed) to 83% and the growth performance of shrimp from
247.78 g (without seaweed) to 350.20 g. Remaining nitrogen excreted by shrimp
amounted to 15.36 g, which was mainly (14.62 g) utilized by seaweed to form a
biomass of 16.90 kg. Therefore, polyculture systems using seaweed seem to act
more efficiently with regard to nutrient accumulation.
75

Introduction
Shrimp aquaculture has developed quickly since the 1980s in Southeast Asian
countries including Indonesia. However, the rapid industrial growth of
aquaculture has raised environmental concerns about eutrophication and depletion
of natural habitats (Naylor et al., 2000; Zhang, 2003; Zhou et al., 2003; Mao et al.,
2006). Animal mariculture and other anthropogenic activities generate large
quantities of organic and inorganic waste. Especially feed supply results in
excretory products and discharge of uneaten feed, which releases up to 70% of
dietary nutrients into the environment (Porter et al., 1987). Released nutrients
increase eutrophication processes (Neori et al., 1991; Rathakrishnan, 2001) and
the accumulation of acute toxic substances for aquatic animals (Troell et al., 1999;
Neori et al., 2001).
Integrated multitrophic aquaculture techniques are good candidates to overcome
these sustainability problems (Ruddle and Zong, 1988; Primavera, 1991;
Hishamunda and Ridler, 2004). These systems have been proposed as a tool for
developing environmentally sounded aquaculture practices and resource
management within a balanced coastal ecosystem approach (Troell et al., 2003;
Neori et al., 2004). The polyculture of aquatic animals and plants reduces the
environmental impact of the culture system compared to monoculture because of
the reutilization of dissolved and particulate waste products (Petrell et al., 1993).
Seaweed can absorb significant amounts of waste nutrients, controlling
eutrophication, and consequently, improving the health and stability of marine
ecosystems (Buschmann et al., 2001; Chopin et al., 2001; Troell et al., 2003; Fei,
2004; Neori et al., 2004). The physiological mechanisms of seaweed biofiltration
have been studied in, e.g. filter-feeding bivalve culture systems (Fang et al.,
1996), fish cage farms (Troell et al., 1997; Hayashi et al., 2008), shrimp culture
ponds (Jones et al., 2001; Nelson et al., 2001), and polyculture ponds containing
shrimp Penaeus vannamei and seaweed Gracillaria verrucosa (Ihsan et al.,
submitted).
In an aquaculture system most of the nitrogenous and phosphorus dissolved
inorganic waste products are excreted in the form of ammonium (NH4 + ) and
phosphate (PO4 3- ). Both compounds are potentially toxic to aquatic organisms and
76

increase eutrophication potential. The mechanical and chemical treatment and
other processes to remove the excess of ammonium and phosphate from waste
water and the culture ponds are very expensive and may also affect the
environment (Troell et al., 2003). Seaweed has been studied in recent years for
nutrient removal strategies. This treatment technique is considered to be the most
inexpensive and environmentally sounded clearification way (Buschmann et al.,
1996; Rathakrishnan, 2001; Neori et al., 2004).
The subject of the present study is the parameterization of the rate of nitrogen
uptake by the seaweed from shrimp wastewater of polyculture systems in order to
reduce the nutrient releases into the environment.
Material and Method
The experiment was conducted in Sungai Buntu, West Java over a 40-day period
from August–September 2009 in an indoor laboratory facility (Figure 1). This
study used a completely randomized block design conducted in two phases. Phase
I aimed to determine optimal stocking densities and ammonia excretion rates of
shrimps, whereas the second phase quantified the nitrogen assimilation of
seaweed at four seaweed stocking densities.
Location of experiments
(Sungai Buntu-West Java)
Figure 1. Map of Research Institute for Brackish water fisheries, West Java,
Indonesia
77

The experiment in phase I was divided into 3 treatments using glass aquaria with
shrimp stocking densities of 5, 10, and 15 ind/100 liters of water. For each
treatment two replications were conducted. Phase I was carried out for 1 week.
The aquarium was filled with 100 liters of aerated sea water, and the environment
was controlled with temperatures in the range of 27–30 ° C and salinity ranging
from 25 to 28 ppt. Shrimp were fasted for one day then weighed; afterwards they
were fed for one week and weighed again at the end of the experiment. On the last
day, shrimp were transferred into two containers (10 liters), which had been filled
with aerated sea water and exposed for 8 hours to ultraviolet (UV) light for
disinfection of other nitrogen-consuming organisms. Stocking density in the
containers was one shrimp per 5 liters. Two containers without shrimp served as a
control. Sampling was carried out 6 times at 1 h intervals from 0–5 h. Afterwards
ammonium nitrogen was measured in accordance to APHA standard methods
(1995).
In phase 2, nitrogen assimilation of seaweed at four stocking densities of seaweed
was investigated with 3 replications using concrete tanks (3 m³ volume, 1 m * 3 m
* 1 m). Seaweed stocking densities were 0 g/l (Treatment A), 3.125 g/l (Treatment
B), 6.250 g/l (Treatment C), and 9.375 g/l of seaweed (Treatment D).
Determination of seaweed density was modified from Rathakrishnan (2001).
Shrimp stocking density used in experimental phase 2 amounted 5 shrimp/100
liter with an initial weight of 6–7 g, based on the outcome of growth and survival
results of phase 1 experiments. Individual and total weight of the replicate tank
loading groups was not significantly different (P>0.05).
The shrimp were fed a commercial diet with a protein content of 40% four times a
day, i.e. at 07.00, 12.00, 17.00 and 22.00. The feed quantity was dynamically
assigned to shrimp biomass increase estimated from control sampling. The daily
feed ratio provided 7% of the weight of shrimp at sampling, modified in
accordance with Baliao and Tookwinas (2002). Subsamples of shrimps (number
of individuals) and algae from each tank were weighed every week.
78

Sampling
In both phases of the experiment, the following water quality parameters were
measured: temperature, salinity, dissolved oxygen (DO), pH, ammonium, nitrate,
nitrite, and total nitrogen (TN). Additionally, the number and weight of shrimp
and survival rate, growth rate and feed conversion ratio (FCR) were assessed.
In phase 2, every week, ammonium, nitrate, nitrite, and total nitrogen were
analyzed. The samples were taken over a 24-hour period at 3 hour intervals. Water
samples were taken from 20 cm below the water surface. Everyday at 08.00 and
16.00, the water temperature, salinity, and dissolved oxygen (DO) were monitored
in situ with a portable water-quality analyser (TOA model WQC-20A Electronics
Ltd., Japan). Water samples were collected using plastic bottles attached to the
end of a stick. They were immediately filtered through Whatman GF/F filters 0.7
µM millipore for soluble nutrients analyses (NO3 - , NO2 - , NH4 + ). The ammonium
concentration in the filtrate was measured immediately following filtration. Total
nitrogen (TN), nitrate, and nitrite concentrations were measured using the APHA
(1995) standard method. The standard methods for the determination of
ammonium, nitrite and nitrate were based on moderate alkaline solution with
hypochlorite, diazotization, and cadmium reduction followed by diazotization,
respectively. The spectrophotometer wave lengths for ammonium, nitrite, and
nitrate were 630 nm, 542 nm, and 542 nm, respectively. The nutrient analyses
were performed using a spectrophotometer (Shimadzu UV-2400).
The nitrogen content in the feed, shrimp, and seaweed was measured using the
Kjeldahl method. Subsamples of shrimp (quantity) and algae (quantity) were
analyzed at the beginning and the end of the experiment to assess changes in
nitrogenous composition.
Calculation
Survival Rate (SR) was calculated as a ratio of the shrimps quantity at stocking
and sampling time using the following formula:
SR = (Nt / N0) X 100%
With: SR = survival rate
79

N 0 = number of shrimp on day 0 (individuals)
Nt = number of shrimp on day t (individuals)
Specific growth rate were calculated with the formula (Busacker et al., 1990):
SGR = ((ln Wt - ln W0) / t) * 100%
With: SGR = Specific growth rate
W 0 = weight on day-0 (g/individual)
Wt = weight on day-t (g/individual)
t = time of experiment (day)
The feed conversion ratio (FCR) was calculated as the ratio between the amount
of feed given to shrimp biomass increment at a certain period (NRC, 1977) using
the formula:
FCR = F / ΔB
With: FCR = feed conversion ratio
F = amount of feed given during experiment (kg)
ΔB = addition of shrimp biomass during experiment (kg)
Nitrogen retention was calculated based on the following equation:
NR = ∑TNt - ∑TN0
With: NR = Nitrogen retention (g)
∑TNt = amount of total nitrogen on day-t (g)
∑TN0 = amount of total nitrogen on day-0 (g)
Ammonium excretion was calculated based on the following equation (Yigid,
2005):
AE = ((Nt – N0)/(W * Tt-0))
With: AE = Ammonium excretion (mg-N/g/h)
Nt = Ammonium concentration on time-t (mg/l)
N0 = Ammonium concentration on time-0 (mg/l)
W = weight of shrimp (g)
Tt-0= sampling interval
80

Statistics
Growth rate, survival rate, nitrogen retention and nutrient fluxes from experiments
were analyzed statistically. All data were checked for normality (Kolmogorov-
Smirnov test) and homogeneity of variances (HOV, Brown Forsythe test).
Differences of means of triplicates in phase 2 were evaluated for significance by
the range tests of Tukey HSD (P

ammonium excretion was 0.004 mg/g/h. The results of the first phase ammonia
excretion trial are summarized in Table 2.
Table 2. Ammonium Excretion
Containers
Time observation (h)
0 1 2 3 4 5
Weight
of
shrimp
(g)
Ammonium
excretion
(mg/g/h)
Replicate1 0.356 0.438 0.535 0.603 0.671 0.620 7.89 0.005
Replicate2 0.544 0.586 0.540 0.580 0.660 0.643 8.21 0.003
Average 0.450 0.512 0.537 0.591 0.665 0.631 8.05 0.004
Phase II
Growth of shrimp
The total weight of shrimp at the end of the experiment was significantly different
between treatments (P0.05) among the treatment without seaweed
and the treatment with stocking of seaweed 3.125 g/l (B), 6.250 g/l (C), and 9.375
g/l (D) (Figure 2).
The survival rate (SR) of shrimp in phase II, showed that from the first week until
the end of the study there was a significant difference (P

Table 3. Weight, Retention, and FCR
Treatment
A B C D
Total N-Feed (g) 16.44 18.09 16.9 18.41
Start
Weight shrimp (g) 266.41 265.95 269.74 266.81
N shrimp (%) 7.44 7.43 7.53 7.45
Weight Seaweed (g) 1562.6 3125.26 4688.29
N Seaweed (%) 8.06 16.13 24.19
End
Weight shrimp (g) 243.78 a
N shrimp (%) 1.78 a
350.2 b
10.16 b
327.96 c
9.13 b
Weight Seaweed (g) 3255.12 a 5963.78 b
N Seaweed (%) 22.68 a
N-Retention
Shrimp (g) 0.59 a
2.73 b
Seaweed (g) 14.62 a
N production of shrimp 15.85 a
N in water (g) 15.85 a
FCR 2.69 a
15.36 a
0.74 b
1.99 a
Daily Growth rate of
Seaweed (%) 2.62 a
24.67 a
1.6 c
8.54 b
15.3 a
6.76 c
2.02 a
2.31 a
314.71 d
9.22 b
6563.24 b
36.65 b
1.78 c
12.46 c
16.63 a
4.18 c
2.24 a
1.20 b
Values with the same superscript letter do not differ significantly (P>0.05)
83

Weight (g)
18.00
17.00
16.00
15.00
14.00
13.00
12.00
11.00
10.00
a
a
Weight Average of Shrimp
a
a
0 1 2 3 4 5
Time (Week)
a
a
a
a
Seaweed 0 g/l
Seaweed 3.125 g/l
Seaweed 6.250 g/l
Seaweed 9.375 g/l
Figure 2. Individual weight of shrimp during the experimental period, values
Survival rate (% )
are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
120.00
100.00
80.00
60.00
40.00
20.00
0.00
b b
a a
Survival Rate
0 1 2 3 4 5
b
a
Time (Week)
b
a
b
b
Seaweed 0 g/l
Seaweed 3.125 g/l
Seaweed 6.250 g/l
Seaweed 9.375 g/l
Figure 3. Survival Rate of shrimp during the experimental period, values are
mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
84

Growth of seaweed
The daily growth rate of seaweed was significantly different (P0.05).
The lowest FCR value occurred in the treatment with stocking density of seaweed
3.125 g/l (treatment B) i.e. 1.99 and the highest occurred in the treatment without
seaweed (treatment A) i.e. 2.69.
Nitrogen retention of shrimp in each treatment was significantly different
(P

Concentration (m g/l)
Concentration (m g/l)
3.5
3
2.5
2
1.5
1
0.5
0
a
b
a
b
Total Nitrogen
0 1 2 3 4 5
a
Time (Week)
b
a
b
b
b
Seaweed 0 g/l
Seaweed 3.125 g/l
Seaweed 6.250 g/l
Seaweed 9.375 g/l
Figure 4. Concentration of total nitrogen (TN) during the experimental
1.2
1
0.8
0.6
0.4
0.2
0
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
a
b
b
b
b
b
c
a
Ammonium
0 1 2 3 4 5
d
c
b
Time (Week)
a
c
a
b
Seaweed 0 g/l
Seaweed 3.125 g/l
Seaweed 6.250 g/l
Seaweed 9.375 g/l
Figure 5. Concentration of ammonium-nitrogen (NH4 - -N) during the
experimental period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
86

Even though fresh water was supplied to the ponds, the ammonium-nitrogen
concentrations occurred in different amounts in all treatments. The highest
concentration of ammonium occurred in treatment A (without seaweed) at week 2,
i.e. 0.94 mg/l (Figure 5).
Nitrate showed a different pattern as well. The peak nitrate concentration in all
treatments was 0.009 mg/l. Treatment (A) occurred at week 1, treatment (B) at
week 2, treatment (C) at week 4, and treatment (D) at week 3 (Figure 6). While
nitrite showed the same pattern in all treatments. The peak concentration of nitrite
in all treatments occurred at week 2 and not significantly different (P>0.05).
Treatment (A) was 0.009 mg/l, treatment (B) 0.007 mg/l, treatment (C) 0.008
mg/l, and treatment (D) 0.009 mg/l (Figure 7).
Concentration (mg/l)
0.012
0.01
0.008
0.006
0.004
0.002
0
a
a
b
b
c
a
Nitrate
0 1 2 3 4 5
b
c
Time (WeeK)
Seaweed 0 g/l
Figure 6. Concentration of Nitrate-nitrogen (NO3 - -N) during the
experimental period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
87
a
a
c
b
Seaweed 3.125 g/l
Seaweed 6.250 g/l
Seaweed 9.375 g/l

Concentration (m g/l)
0.01
0.009
0.008
0.007
0.006
0.005
0.004
0.003
0.002
0.001
0
a
a
a
a
a
a
Nitrite
0 1 2 3 4 5
a
Time (Week)
a
a
a
a
a
Seaweed 0 g/l
Seaweed 3.125 g/l
Seaweed 6.250 g/l
Seaweed 9.375 g/l
Figure 7. Concentration of Nitrite-nitrogen (NO2 - -N) during the experimental
period, values are mean of triplicate ponds (n=3)
Values with the same superscript letter do not differ significantly (P>0.05)
Discussion
Utilization of dissolved nitrogen by seaweed in the water aims to reduce the waste
burden in the aquaculture media. Nitrogen content of the treatment using the
seaweed was increased but it did not get too high (Figure 4), proving that the
seaweed Gracillaria verrucosa could take up nitrogen. The seaweed could make
use of ammonium through a diffusion process using all parts of its body. The
higher the ability of seaweed to absorb the dissolved ammonium, the greater its
growth. This means that the content of nitrogen will also further increase in the
seaweed biomass, which can be seen from nitrogen seaweed bladder increases.
Nitrogen is necessary for the seaweed in the regulation of metabolism and
reproduction. Growth and biomass can be achieved properly if the seaweed
receives sufficient nitrogen. Uptake of nitrogen by seaweed Gracillaria verrucosa
is not only a function of external nitrogen concentration, but also of the internal
concentration in the plant net. Retrieval and storage of nitrogen by the seaweed
can be affected by the concentration of dissolved inorganic nitrogen in water and
88

influenced by ecological fluctuations of nitrogen in plant tissues. Low nitrogen
concentrations in the environment cannot meet the needs of seaweed for nitrogen
for further usage. But the seaweed has the ability to assimilate and store nutrients
from its surroundings, especially at low concentrations. Nitrogen dry weight
content in treatments C and D were lower than treatment B. Presumably, although
the amount of nitrogen in the form of nitrate and nitrite in water is high but
Gracillaria was less able to utilize it. This is consistent with the finding that the
most nitrogen absorbed by the seaweed is nitrogen in ammonium form (Troell et
al., 1999). To meet the need for nitrogen, the reserves stored in the network are
used prior to growth.
The ability of seaweed in taking up nitrogen from shrimp aquaculture waste in
different treatments during the four weeks of maintenance in treatment B,
seaweed was capable of utilizing dissolved nitrogen from shrimp waste up to
14.62 g, so that the weight of seaweed would be increasing twice. If it was
calculated per hour, then the seaweed is capable of absorbing dissolved nitrogen
at a rate of 0.013 g-N/kg/hr. The utilization of nitrogen by seaweed in this study is
higher than the results of the previous study (Ihsan et al., submitted). In the
previous study, the TN of seaweed in polyculture system was 3.5%. In phase 2 of
the study, the absorption of nitrogen by seaweed was three times greater than the
production value of nitrogen excretion of shrimp per hour and kilogram in study
phase I (Table 1). This means that dissolved nitrogen excretion of the shrimp can
be utilized optimally by the seaweed.
Utilization of ammonium at treatments C (6.250 g/l of seaweed) and D (9.375 g/l
of seaweed) is greater than for treatment B (3.125 g/l of seaweed) only at the
beginning of the study (first week). This condition does not last as long as the
amount of ammonium reduced. To meet nutrient needs, seaweed then utilizes
nitrate and nitrite. It can be seen from the steady depletion of nitrate and nitrite
content in aquaculture media. In general, seaweed gradually absorbs nitrogen, i.e.
ammonium> nitrate> nitrite (Troell et al., 1999). Utilization of nitrate and nitrite
by the seaweed is less efficient because nitrate and nitrite must first be reduced
before used by seaweed. Seaweed using nitrate for the metabolism need
involvement of nitrate reductase enzyme (Patadjai, 1993). Absorption of nitrate
89

and nitrite by the seaweed is influenced by the concentration of ammonium in the
media. Due to the nitrogen used by seaweed in treatments C and D being nitrate
and nitrite, then the growth of seaweed was not as fast at the beginning of more
research utilizing ammonium. Soriano (2002) reported the growth of seaweed
during the first two weeks as rapid, but that it then declined until the end.
Maintenance of seaweed Gracillaria verrucosa in drain ponds of shrimp in the
first 15 days reached 8.8% and then continued to decline.
Glen et al. (2002) showed that seaweed Gracillaria parvispora cultivation in
shrimp pond effluent water could increase the nitrogen content in the thallus of
1% to 3.5% with a growth rate of 8–9% per day, which is higher than the growth
rate of seaweed fed chemical fertilizers i.e. only 4–5% per day. The content of
ammonium in treatment A (without seaweed) in the second week decreased
drastically. This is due to the oxidation of ammonium into nitrite and then into
nitrate. The content of nitrite and nitrate increased until reaching a peak; this is
due to the aeration of the culture medium so that the oxygen demand for oxidation
processes is met. Boyd (1999) described the process of oxidation with ammonium
as the energy source, CO2 as a carbon source and O2 the source for the oxidation
process. The oxidation process also occurred in treatments B, C, and D but in
small quantities because the ammonium first utilized by seaweed. Besides that,
seaweed also produces oxygen from photosynthesis rest. Xu (2008) reported
Gracillaria cultivation can improve other aspects of water quality instead of
increasing DO. Its photosynthesis produces DO, which promotes decomposition
of organics. Density raft culture of Gracillaria verrucosa impedes the water
circulation and may reduce chemical oxygen demand (COD) in the water column.
In addition, several species of Gracillaria can produce oxygen under low light
conditions, such as in rainy days and remediate anoxia (Xu et al., 2004). Neori et
al. (2004) reported that seaweed Gracillaria sp. is capable of supplying oxygen
(DO) of 2.86 mg/l for 24 hours to the maintenance medium using polyculture with
milkfish, shrimp, and seaweed.
Ammonium concentrations increased again in all treatments during week 4, with
the highest value in treatment (D). This is due to the feeding; the higher residual
and fecal excretion issued shrimp and dead seaweed. Additionally the maximum
90

growth of seaweed was achieved in the third week. When maximum growth has
been achieved then the absorption of nitrogen will decrease.
Water quality greatly affects the growth of shrimp. Good water quality is capable
of supporting shrimp life, thereby increasing the appetite of the shrimp. Based on
the value of FCR and the retention of each treatment, it is known that the FCR
indicates the efficiency level of the feed utilization by shrimp as well as affecting
the nutrient waste load discharged into the environment. The smallest FCR
occurred in treatment B (1.99) with a biomass of 350.2 g and survival rate of
82.67%. This means that the high feed utilization by shrimp for growth causes the
retention value also to be high (2.73 g). In comparison to the global average
shrimp feed conversion ratio of around 2.0, the observed feed conversion were
quite good (Tacon, 2002).
The concentration of ammonium and nitrite in treatment (B) was lower compared
with other treatments. To grow the shrimp from 265.95 g to 350.16 g, 15.36 g of
nitrogen waste were generated (Table 3). Most of the waste (14.62 g) was
absorbed by the seaweed, which enabled it to grow to1.69 kg, while the remaining
0.74 g of residual waste remained in the water. The smaller the concentration of
nitrogen remaining in the water, the more effective the utilization rate of nitrogen
by the seaweed.
Conclusions
The seaweed Gracillaria verrucosa can be cultivated in polyculture together with
the shrimp Penaeus vannamei. The ability of seaweed in taking up nitrogen from
the water would make the farming environment better and support shrimp
production. This can be seen from the survival rates (SR) being significantly
different (P

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92

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94

General Discussion
System performance
In recent years, polyculture system has been proposed as a key to develop
environmentally sounded aquaculture practices and resource management through
a balanced ecosystem approach to avoid pronounced shifts in coastal areas. Feed
based aquaculture needs to be integrated with extractive aquaculture. Multitrophic
polyculture system provides bioremediation potential, mutual benefits to the cocultured
organism, economic diversification by creating other value added
products and increase profitability per cultivation unit.
In chapter one, based on a literature study polyculture system are described as the
practice of culturing more than one species of aquatic organism in the same
system. The motivating principle is that fish/shrimp production may be
maximized by raising a combination of species having different food habits. The
concept of polyculture of fish/shrimp is based on the concept of total utilization of
different trophic and spatial niches of a pond in order to obtain maximum
fish/shrimp production per unit area (Edward, 1992; Chiang, 1993; Qian et al.,
1996). The main advantages of polyculture systems is that wastes of one resource
user become a source for the others (Neori et al., 2004).
The use of seaweed integrated with fish/shrimp cultures has been studied in open
water and land-based system condition in Israel, Portugal, Brazil, and Indonesia
(Neori et al., 1998; Schuenhoff et al., 2003; Lombardi et al., 2006; Ihsan et al.,
submitted). General concepts about nutrient uptake by seaweed can be found in
Harrison and Hurd (2001). To optimize the seaweed component of an integrated
aquaculture system, particular attention should be given not only to physical and
chemical factors such as light, temperature, effluent nutrient concentration and
flux, and water motion but also to biological factors such as plant variability
including tissue type, plant age, etc.
Xu (2008) reported the Gracillaria cultivation can improve other aspect of water
quality instead of increasing DO. Its photosynthesis produces DO that promotes
decomposition of organics. Density raft culture of Gracillaria impedes the water
circulation and may decrease chemical oxygen demand (COD) in the water
95

column. In addition, several species of Gracillaria can produce oxygen under low
light condition, such as in rainy days and remediate anoxia (Xu et al., 2004).
In chapter two, polyculture systems using seaweed Gracillaria seem to act more
efficiently with regard to nutrient accumulation than in monoculture. The average
ammonium-nitrogen concentration over the whole period was 0.24 mg/l in
polyculture while in monoculture 0.37 mg/l of ammonium-nitrogen were
analyzed. Survival rate of shrimp in polyculture and monoculture were 86.32%
and 69.17%, respectively.
Growth performance
Overall, the growth performance of shrimp in polyculture was better than
monoculture systems. In chapter two, the average final weight of shrimp was 24.9
± 1.8 g for polyculture systems with survival rates of 86.3%. For monoculture, the
weight of shrimp was 20.8 ± 1.05 g and survival rate accounted 69.17%. Survival
rate of shrimp in polyculture was significantly higher than in monoculture, and the
weight of shrimp as well. The feed conversion ratio (FCR) for the polyculture and
monoculture system in this study were significantly (P0.05). The average weight of shrimp at harvest was 24.73
± 0.71 and 23.45 ± 1.43 g/ind for polyculture I and II, respectively. Specific
growth rate (SGR) for shrimp in polyculture I and II was not significantly
different (P>0.05) with an average value over the 90-day experiment of 4.5%/day
and 4.4%/day, respectively.
Shrimp growth and production were reported to be basically related to the
environmental condition (Songsangjinda, 1994). Results from this study showed
clear differences in performance parameters between monoculture and polyculture
systems. This result may indicate that seaweed play a vital role on system
productivity. This result is in agreement with the observation of Troell et al.
(1997) and Soriano et al. (2002). They reported that the environmental conditions
for growth of shrimp in polyculture systems is better than in monoculture. Apart
96

from removing nutrients, the seaweed as co-cultured organisms may contribute to
the oxygen budget of the ponds.
Fluctuation of water quality in ponds is the result of variation in nutrients loading
from feed and biological processes of shrimp and organisms in water column
(Burford and Williams, 2001).
In chapter three, the water quality in polyculture systems were in optimal ranges
for fish and shrimp indicated by a high survival rate (SR) during the 90-day
period. Results from this study showed, that no significant differences in shrimp
performance between the two polyculture systems. Shrimp growth and production
correlated with stocking density, feeding management and water quality. The
main nutrients were introduced into the ponds via feed application. This suggests
that pellet feed may properly promote nutrient excretion by shrimp and fish that
can cause hypoxic conditions due to decomposition of organic material by
bacteria in the bottom layer of the pond.
Nutrient flux
The two significant components of the pond environment are the pond water and
sediment which interact continuously to influence the culture environment. Pond
sediment can be further divided into the pond soil component (the pond bottom
and walls) and the accumulated sediment component (Briggs and Funge-Smith,
1994). In the investigation by Funge-Smith and Briggs (1998), around 90% of
nitrogen input to the pond came from feed but most of the nitrogen (70-80%) was
not retained in shrimp body, but remain in the pond as accumulated sediment.
In chapter two, the ammonium concentration increased gradually in monoculture
and polyculture systems and orthophosphate concentration progressively
increased as well. Though well water was supplied to the pond, the ammoniumnitrogen
concentrations in monoculture increased from 0.005 to 0.779 mg/l, with
an average concentration of ammonium-nitrogen during the 100 days period of
0.37 mg/l. In polyculture system, it increased from 0.003 to 0.483 mg/l, with an
average of 0.24 mg/l. Therefore, ammonium-nitrogen concentrations in
monoculture system were significantly higher in comparison to polyculture
system (P

Ideally, nutrient process in polyculture system with two or more ecologically
compatible species should be balanced, waste from one species are recycled as
fertilizer or feed by another without conflicting with each other (Neori et al.,
2000). By integrating fed mariculture (fish and shrimp) with extractive
mariculture (seaweed), the wastes of one resource consumer become a source
(fertilizer or feed) for others in the system. To get more information about
optimum nutrient utilization, the absorbtion of nitrogen derived by shrimp waste
into seaweed Gracillaria verrucosa is described in chapter four.
In chapter four, the total nitrogen (TN) concentration increased gradually. It
shows that the concentration of total nitrogen (TN) increased in polyculture and
monoculture system. The highest increase of TN occurred in monoculture system
(treatment without seaweed) from 0.82 to 2.73 mg/. The lowest increase occurred
in polyculture using seaweed at stocking densities of 9.375 g/l (treatment D)
ranging from 0.55 to 1.46 mg/l.
Mass balance
In chapter two, a mass balance model was developed for total nitrogen and total
phosphorus to estimate their fluxes. From the total nitrogen and total phosphorus
input, 24.2% and 5.3% were incorporated in 335.7 kg/1200 m 2 shrimp weight gain
in monoculture, while 30.8% and 6.9% were incorporated in 501.5 kg/1200m 2
shrimp weight gain and 3.5% and 2.4% were incorporated in 325 kg/1200 m 2
seaweed Gracillaria in polyculture system.
In chapter three, mass balance model in this study showed nutrient utilization in
the evaluated polyculture systems. TN and TP incorporated in shrimp and
seaweed in polyculture I was lower than polyculture systems II but not significant
different.
Conclusion
Responsible aquaculture practices should be based on a balanced ecosystem
management approach, which incorporate the biological and environmental
function of a diverse group of organisms into a unified system that maintains the
natural interaction of species and allows an ecosystem to function sustainable. In
98

general, shrimp and fish aquaculture using additional feed produces a large
amount of waste, including nitrogen and phosphorus that could be released into
the aquatic environment if not treated.
Integrated seaweed aquaculture systems have been suggested as a possible
solution for securing an increasing and environmentally sounded production of
future supply.
Normally, production of main target organism in polyculture system could
decrease due to competition in space and nutrient utilization with co-cultured
organisms. The results in this study suggest that seaweed can not only serve as an
effective biofilter for shrimp ponds but also can increase shrimp production even
integrated with fish within the same system. The weight and survival rate of
shrimp in polyculture systems were higher than in monoculture.
The ability of seaweed in taking up nitrogen from the water would make the
farming environment better and support shrimp production. Thus polyculture
systems using seaweed seem to act more efficiently with regard to nutrient
accumulation.
References
Briggs, M. R. P., and Funge-Smith, S. J. 1994. A nutrient budget of some
intensive marine shrimp ponds in Thailand. Aquacult. Fisheries Manage.
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Chiang, Y. M. 1993. Seaweed cultivation in Taiwan. In Liao, I. C., Cheng, J. H.,
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Edward, P. 1992. Reuse of human wastes in aquaculture, a technical review.
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Funge-Smith, S. J. and M. R. P. Briggs. 1998. Nutrient budgets in intensive
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Ihsan, Y. N, K. J. Hesse, N Holmgren, C Schulz. Submitted. A Comparison of
Nutrients Fluxes in Monoculture and Polyculture Systems for Shrimp
(Penaeus vannamei) and Seaweed (Gracillaria verrucosa) Production.
Submitted to the journal of World Aquaculture Society.
Lombardi, J. V., de Almeida-Marques, H. L., Pereira, R. T. L., Barreto, O. J. S.,
de Paula, E. J. 2006. Cage polyculture of the Pacific white shrimp
Litopenaeus vannamei and the Philippines seaweed Kappaphycus
alvarezii. J. Aquacult. 258:412-415.
Neori, A., Ragg, N. L.C., Shpigel, M. 1998. The integrated culture of seaweed,
abalone, fish and clams in modular intensive land-based systems: II.
Performance and nitrogen partitioning within an abalone (Haliotis
tuberculata) and macroalgae culture system. Aquacult. Eng. 17:215-239.
Neori, A., T. Chopin T, M. Troell, A. H. Buschmann, G.P. Kraemer, C. Halling,
M. Shpigel, C Yarish. 2004. Integrated aquaculture: rationale, evolution
and state of the art emphasizing seaweed biofiltration in modern
mariculture. Aquaculture 231:361–391.
Qian, P. Y., C. Y. Wu, M. Wu, Y. K. Xie. 1996. Integrated cultivation of red alga
Kappaphycus alvarezii and the pearl oyster Pinctada martensi.
Aquaculture 147: 21-35
Schuenhoff, A., Shpigel, M., Lupatsch, I., Ashkenazi, A., Msuya, F. E., Neori, A.
2003. A semi-recirculating, integrated system for the culture of fish and
seaweed. Aquaculture 221:167–181.
Soriano, E. M., C Morales, W. S. C Moreira. 2002. Cultivation of Gracillaria
(Rhodophyta) in shrimp pond effluents in Brazil. Aquaculture Research
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shrimp aquaculture. Report prepared under the World Bank, NACA,
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environment, published by consortium. 69.
Troell, M., C Halling, A Nilsson, A. H Buschmann., N Kautsky, L Kautsky. 1997.
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Bangiophyceae) and salmon cages for reduced environmental impact and
increased economic output. Aquaculture 156:45–61.
Xu, Y. J., N. Z. Jiao, L. M. Qian. 2004. Nitrogen nutritional identities of
Gracillaria as bioindicators and restoral plants (in Chinese with English
abstract). Journal of Fishery Sciences of China. 11. 276-281.
Xu, Y. J., J. Fang, Q. Tang, J. Lin, G. Le. 2008. Improvement of water quality by
the macroalga, Gracillaria lemaneiformis (Rhodophyta), near aquaculture
effluent outlets. World aquaculture society. 39. 549-555.
101

General Summary
Feed based shrimp and fish aquaculture produces a large amount of waste,
including nitrogen and phosphorus that is released to the aquatic environment
without treatment. The present thesis is focussed on various polyculture systems
using shrimp Penaeus vannamei, fish Oreochromis sp. and seaweed Gracillaria
verrucosa. Seaweed cultivation in integrated polyculture system appears to be a
viable approach to reduce nutrients discharge to the environment. Seaweed can be
efficient in removing nutrients from effluents of intensive fish and shrimp farm.
By integrating fed with extractive forms of aquaculture, the wastes of one
resource user become a source for the others.
Chapter one presents an introduction of nutrient fluxes in various polyculture
systems and implication for its sustainability. A review of scientific literature
illustrates important aspects to implement polyculture system using seaweed as
biofilter. The production of seaweed in cage culture can be successfully integrated
in the production of fish and shrimp. Regarding the environmental benefits of
integrated seaweed and fish or shrimp production, seaweed culture can also
benefit by increasing their economic viability. Integrated seaweed aquaculture
systems have been suggested as a possible solution for securing an increasing and
environmentally sounded production of future supply of fish and seafood.
Chapter two compares performance and nutrient fluxes of monoculture and
polyculture system. Therefore triplicate ponds of 1200 m² were stocked with
seaweed (0.04 kg/m²) and 20 individuals of shrimp (0.22 ± 0.016 g/ind)/m 2 . The
culture period lasted 100 days and water samples to describe nutrient fluxes were
taken every 10 days. Results indicate that polyculture systems using seaweed
seem to act more efficiently with regard to nutrient accumulation. The average
ammonium-nitrogen concentration over the whole period was 0.24 mg/l in
polyculture while in monoculture 0.37 mg/l of ammonium-nitrogen were
analyzed. From the total nitrogen and total phosphorus input, 24.2% and 5.3%
were incorporated in 335.7 kg/1200 m 2 shrimp weight gain in monoculture, while
30.8% and 6.9% were incorporated in 501.5 kg/1200m 2 shrimp weight gain and
102

3.5% and 2.4% were incorporated in 325 kg/1200 m 2 seaweed in polyculture
system.
A comparative study on polyculture systems using various combinations of
shrimp, seaweed and fish was conducted in chapter three in order to calculate
nutrients fluxes and mass balances. Therefore, triplicate ponds of 1000 m 2 size
were stocked with 0.4 kg/m 2 seaweed and 15 shrimps/m 2 (polyculture I), and
triplicate ponds of size 1000 m 2 were stocked with 0.4 kg/m 2 seaweed, 15
shrimps/m 2 , and 0.25 fish/m 2 (polyculture II). A mass balance model was
developed for total nitrogen and total phosphorus to estimate their fluxes. From
total nitrogen and total phosphorus input, 46.79% and 14.99% were incorporated
in 313.08 kg/1000 m 2 shrimp weight gain in polyculture system I, while 41.47%
and 13.47% were incorporated in 291.25 kg/1000 m 2 shrimp weight gain and
13.64% and 5.09% were incorporated in 40.67 kg/1000 m 2 fish weight gain in
polyculture system II. These results suggest that no significant differences in
shrimp performance between the two polyculture systems (P>0.05) could be
observed.
Chapter four evaluated the nutrient absorption efficiency of combined shrimp and
seaweed production. Therefore, triplicate concrete tanks, with a volume of 3 m 3 ,
were stocked with shrimp (6–7 g, 5 ind/100 litres) and seaweed in densities of 0
g/l, 3.125 g/l, 6.250 g/l, and 9.375 g/l. The use of seaweed at a density of 3.125 g/l
in shrimp polyculture showed the highest ability for nitrogen assimilation
originating from shrimp waste. This treatment increased shrimp survival rate from
63% (without seaweed) to 83% and the growth performance of shrimp from
247.78 g (without seaweed) to 350.20 g. Remaining nitrogen excreted by shrimp
amounted to 15.36 g, which was mainly (14.62 g) utilized by seaweed to form a
biomass of 16.90 kg. Therefore, polyculture systems using seaweed seem to act
more efficiently with regard to nutrient accumulation and beneficial effects on cocultured
organisms.
103

Zusammenfassung
Die futtermittelbasierte Aquakultur kann zu einer Anreicherung von
Stoffwechselendprodukten führen, die die Qualität des genutzten Gewässers
erheblich beeinträchtigen können. In der vorliegenden Arbeit wurde deshalb die
Reduzierung von Nährstoffemissionen der Aquakultur durch multitrophe
Haltungssysteme untersucht. Hierzu wurden verschiedene Kulturverfahren von
Tilapia, Shrimp und Makroalgen unter praxisgleichen Bedingungen in Indonesien
untersucht.
Kapitel eins der vorliegenden Arbeit führt thematisch ein und beschreibt die
grundlegenden Prozesse im Nährstoffkreislauf von Gewässer- und
Aquakultursystemen. Aufgrund der vielfältigen gelösten und partikulären
Nährstofffraktionen in Aquakultursystemen kann nur auf Basis von multitrophen
Systemen eine relevante Nährstoffausnutzung realisiert werden. Anhand vieler
Untersuchungen aus der Literatur kann dabei auf die besondere Bedeutung von
Algen als Biofilter in einem Polykultur-System hingewiesen werden, da deren
hohe Wachstumspotentiale die anfallenden gelösten Stickstoff- und
Phosphorverbindungen der tierischen Aquakulturproduktion effektiv verwerten,
die Haltungsumwelt für weitere Organismen optimieren und der zusätzlichen
ökonomischen Wertschöpfung dienen. Weiterhin bietet sich die kombinierte
Aufzucht von carnivoren mit omni- oder herbivioren Species an, da somit die
Stoffwechselendprodukte in der niedrigeren Trophieebene effektiv in Biomasse
überführt werden können.
In Kapitel zwei werden die Potentiale von Monokultur- und Polykultursysteme
experimentell miteinander verglichen. Dafür wurden drei Teiche mit identischer
Fläche von 1200 m 2 in Polykultur mit Gracillaria verrucosa (50 kg) und 20
Shrimps/m² (Penaeus vannamei, Anfangsgewicht 0.22 ± 0.016 g) besetzt.
Weiterhin dienten 3 Teiche mit Shrimpmonokultur bei Besatzdichten von 20
Shrimps/m² als Vergleich. Der Versuch wurde über 100 Tage durchgeführt und im
Abstand von 10 Tagen wurden die Wasserinhaltsstoffe erfasst. Die Werte
indizieren, dass das Polykultur-System mit Algen Gracillaria effizienter die
zugeführten Nährstoffe in Biomasse überführen. Die Durchschnittskonzentration
104

von Ammonium-Stickstoff über die gesamte Versuchsperiode betrug
beispielsweise 0.24 mg/l im Polykultur- und 0.37 mg/l im Monokultursystem. In
der Nährstoffbilanzierung zeigt sich, dass aus dem gesamten Stickstoff (TN)- und
Phosporeintrag (TP) 24.2% bzw. 5.3% in 335.7 kg Shrimpsbiomasse in der
Monokultur überführt wurde, während in der Polykultur 30.8% bzw. 6.9% des
eingetragenen TN und TP in 501.5 kg Shrimps und 3.5 % bzw. 2.4% des TN und
TP in 325 kg Makroalgen Gracillaria verrucosa eingebaut wurden.
Im dritten Kapitel wurden das Polykulturverfahren mit Gracillaria-Algen und
Shrimp (Peneaus vannamei, Polykultur I) mit einem dreigliedrigen Verfahren aus
Shrimp (Peneaus vannamei), Fisch (Oreochromis niloticus) und Makroalgen
(Gracillaria verrucosa, Polykultur II) verglichen. Hierfür wurde wiederum ein
triplikater Versuchsansatz mit jeweils drei Teichen mit einer Fläche von 1000 m 2
eingesetzt und mit 0.4 kg/m 2 Makroalgen und 15 Shrimps/m 2 besetzt. In die
dreigliedrigen Polykultursystemteiche wurden zusätzlich 0.25 Fische/m² gesetzt.
Das Fütterungsmanagement berücksichtigte lediglich die Shrimps, die in beiden
Versuchsansätzen mit vergleichbarer Intensität gefüttert wurden. In der
Nährstoffbilanz zeigte sich, dass in Polykultur I aus dem TN- und TP-Eintrag
46.70% und 14.99% in 313.08 kg Shrimpbiomasse umgesetzt wurde, während in
Polykultur II 41.7% und 13.47% in 291.25 kg Shrimps und 13.62% und 5.09% in
40.67 kg m 2 Fisch eingebaut wurden. Die Makroalgen inkorporierten in
Polykultur I 10.56 % und 9.75 % TN und TP, und in Polykultur II vergleichbare
10.94% und 8.83%. Dieses Ergebnis zeigt, dass das Shrimpsaufkommen durch die
Polykultur mit Fischen nicht signifikant beeinträchtigt wird, durch die zusätzliche
Nährstoffbindung jedoch signifikant weniger Nährstoffe aus dem System geführt
werden.
Im abschließenden vierten Kapitel wurde das Nährstoffaufnahmepotential von
variierendem Makroalgenbesatz in Polykultur mit Shrimps untersucht. Dafür
wurden in kleinskaligen Betonsystemen mit einem Volumen von 3 m 3 Garnelen,
Penaeus vannamei, (6-7 g, 5 Ind/100 Liter) und Makroalgen Gracillaria
verrucosa bei verschiedenen Kulturdichten von 0 g/l, 3.125 g/l, 6.250 g/l und
9.375 g/l aufgezogen und die Wachstumsleistungen und Nährstoffbilanzen
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ermittelt. Dabei zeigte sich, dass die Stickstoffaufnahme der Makroalgen bei einer
Besatzdichte von 3.
125 g/l am höchsten ist. Zudem kann eine positive Wirkung auf die Shrimps
festgestellt werden, da sich höhere Wachstumsleistungen (Gesamtendgewicht:
243.78 g ohne Algen; 350.20 g bei Algendichte: 3.125 g/l) und
Überlebensleistungen der Shrimps (63% ohne Algen, 83% bei Algendichte von
3.125 g/l) einstellen. Der aus der Shrimpfütterung stammende Stickstoff (15.36 g)
wurde dabei überwiegend (14.62 g) von den Algen zur Biomassebildung genutzt.
Schlussfolgend kann gesagt werden, dass die gezielte Polykultur von Shrimps-,
Fisch und Makroalgenaufzucht zu einer deutlich verbesserten
Nährstoffausnutzung und damit zu geringeren Nährstoffausträgen aus
Aquakulturen führen können. Die Zusammenhänge zwischen den
unterschiedlichen trophischen Produktionsebenen sind jedoch nur in Teilen
verstanden, so dass weiterhin ein sehr großes Optimierungspotential besteht.
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Danksagung
An dieser Stelle möchte ich den Menschen Dank entgegenbringen, die zum
Gelingen der vorliegenden Arbeit beigetragen haben.
Ich bedanke mich bei meinem Betreuer Herrn Prof. Dr. Carsten Schulz für die
Überlassung des interessanten Themas und das mir geschenkte Vertrauen bei der
Projektbearbeitung.
Herrn Dr. Karl J. Hesse vom FTZ-Buesum und Prof. Dr. Nöel Holmgren der
Universität zu Skövde-Sweden danke ich für die Diskussion.
Dank gilt meinen lieben Kolleginnen und Kollegen vom FTZ/Corelab für die
Unterstützung bei der Versuchsdurchführung und die überaus schöne Zeit in Kiel
und Büsum. Besonders bei Herrn Prof. Dr. Roberto Mayerle, Dr. Peter Weppen,
Britta Egge und Daniela Koch bedanke ich mich, dass ich als Gast in FTZ/Corelab
arbeiten durfte.
Den Kollegen aus Indonesien danke ich für die gute Zusammenarbeit.
Ich bedanke mich bei Herrn Dede Suhendar für die Hilfsbereitschaft bei der
Versuchsdurchführung und die angenehme Büronachbarschaft.
Meinen Eltern danke ich für die wie immer selbstlose Unterstützung jeglicher Art.
Und ganz besonders danke ich euch, Aminuddin Shaleh und Mulyati Aminuddin,
weil ihr mir allzeit Kraft gebt
Mein größter Dank an meine Frau Tri Dewi K P und meine Kinder, Azka Auliya
Yudanegara, Gilang Auliya Fauzin und Fadhlan Auliya Danurdoro für ihre
Unterstützung.
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Name: Yudi Nurul Ihsan
Geburstag: 1.12.1975
Lebenslauf
Gebursort: Bandung – Indonesien
Eltern: Aminuddin Shaleh
Schulausbildung:
Mulyati Aminuddin
1982-1988 SD Melong Asih II Bandung - Indonesien
1988-1994
Studium:
SMAM Garut - Indonesien
1994-1999 Bachelor-Studium “Aquaculture“ an der Bogor Agricultural
University zu Bogor (IPB-Bogor) Indonesien
1999-2002 Master-Studium “Coastal and Marine Resource
Management“ an der Bogor Agricultural University zu
Bogor (IPB-Bogor) Indonesien
Berufliche Tätigkeit:
2002-2005 Wissenschaftliche Mitarbeiter am Center for Coastal and
Marine Resources Study (CCMRS-IPB) Bogor, Indonesien
2005-2008 Wissenschaftliche Mitarbeiter an der Fisheries and Marine
Sciences Fakultät, Universitas Padjadjaran Bandung,
Indonesien
2008-2011 Wissenschaftliche Mitarbeiter bei der Gesellschaft für
Marine Aquakultur (GMA) mbH in Büsum bei Herrn Prof.
Dr. C. Schulz
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