11th ICRS Abstract book - Nova Southeastern University

22.825
Modeling Reef Fish Visual Census Data: Dealing with Zero Inflated Observations.
Alejandro ACOSTA* 1 , Paul KUBILIS 2
1 Fish and Wildlife Research Institute/South Florida Regional Laboratory, Fish and
wildlife Conservation Commission, Marathon, FL, 2 Fish and Wildlife Research Institute,
FWC, Gainesville, FL
Monthly visual surveys (April to December) of reef fish populations in the Florida Keys
were conducted since 2000 using stationary point count sampling methods. Each month,
divers used SCUBA to conduct two 5m radius stationary point counts at 39 sites using a
habitat-based, stratified random sampling design. During each sampling procedure, divers
enumerated and assigned to 5cm size increments all groupers (Serranidae), snappers
(Lutjanidae), hogfish (Labridae), angelfish (Pomacanthidae), butterflyfish
(Chaetodontidae), triggerfish (Balistidae), and a few other species of recreational or
commercial importance. A common feature of many multi-species ecological data sets is
their tendency to contain many zero values, as is the case with visual census data.
Statistical inferences based on such data are likely to be inefficient or inaccurate unless
careful thought is given to how these zeros arise and how to best model them. To
overcome this problem, we developed an exemplary zero-inflated data set and conducted
analyses using Poisson or negative binomial regression models for uninflated or zeroinflated
point counts. We also considered count regression models (hurdle models) in
which the probability of zero counts and the mean of non-zero counts are modeled
separately. In this paper, we propose a framework for understanding how zero-inflated
data sets originate and deciding how to best model them using visual census data.
22.826
Effect Of Marine Protection Areas On The Community Structure Of Coral Reef
Fishes in Kenting National Park, Southern Taiwan
Jung CHEN* 1 , Tung-Yung FAN 2 , Kwang-Tsao SHAO 3
1 Institute of Marine Biodiversity and Evolution, National Dong Hwa University, Taiwan,
Pingdung, Taiwan, 2 National Museum of Marine Biology and Aquarium, Taiwan,
Pingdung, Taiwan, 3 Research Center for Biodiversity, Academia Sinica, Taiwan, Taipei,
Taiwan
The establishment of the marine protection areas (MPAs) is considered an effective way
to protect fishery resources from overfishing, but its effect has not been fully studied. The
branching Acropora corals are important habitats for many fishes because they provide
safe space and food. This experiment compared the community structure characteristics
of fishes of the family Pomacentridae and Chaetodontidae in the large Acropora colonies
of two MPAs (Houbihu and Inlet of the Third Nuclear Power Plant) and two non-MPAs
(Tiaoshi and Little Bay) in the coral reefs of Kenting National Park, southern Taiwan.
The fish communities within three 3¡Ñ3 m of Acropora coral colonies were surveyed by
visual census. Preliminary results showed that the number of species, number of
individuals, and biodiversity index of fishes in the MPAs (6, 66, 1.21 at Houbihu and 5,
65, 1.44 at Inlet of the Third Nuclear Power Plant, respectively) were higher than those in
the non-MPAs (3, 33, 0.3 at Tiaoshi and 3, 3, 1.1 at Little Bay, respectively). These
results suggest that the marine protection areas play an important role in maintaining the
diversity and abundance of coral reef fishes.
Poster Mini-Symposium 22: Coral Reef Associated Fisheries
22.827
Reef Fish Spawning Aggregations in The Bay Of Bengal: Awareness And Occurrence
Jerker TAMELANDER* 1 , Melita SAMOILYS 2 , Shahaama SATTAR 3 , Ukkrit
SATAPOOMIN 4 , Vineeta HOON 5 , JK PATTERSON EDWARD 6 , Stuart CAMPBELL 7 ,
Manish CHANDI 8 , Rohan ARTHUR 8 , Shiham ADAM 3
1 IUCN, Dar es salaam, Tanzania, 2 CORDIO, Nairobi, Kenya, 3 MRC, Male, Maldives, 4 PMBC,
Phuket, Thailand, 5 CARESS, Chennai, India, 6 SDMRI, Tuticorin, India, 7 WCS, Aceh,
Indonesia, 8 NCF, Mysore, India
Reef Fish Spawning Aggregations (FSA) are critical in the life cycle of the fishes that use this
reproductive strategy as sources of seed, but are also highly vulnerable to over exploitation.
FSAs are known to occur in many species of reef fish in the Caribbean, Pacific, and the Western
Indian Ocean. However, with the exception of the Maldives little if any research has been
focused on FSAs in the Bay of Bengal. Interview surveys were conducted among fishing
communities in selected areas of India, Indonesia, Maldives, Sri Lanka and Thailand in order to
determine the level of awareness of FSAs among fishers; which reef fish species form FSAs;
sites of aggregation formation; seasonal patterns; and to assess fishing pressure on and status of
FSAs. Results show that only a minority of fishers possess reliable knowledge of spawning
aggregation sites, species and times. Possible FSAs were reported from all areas studied. FSAs
were confirmed in Vaavu atoll, Maldives, with sites and times identified for groupers
(Epinephelus fuscoguttatus, Plectropomus areolatus and P. pessuliferus). Highly likely FSAs
were identified in Phuket, Thailand, and the Gulf of Mannar, India, with opinions of species and
spawning aggregation timings, including lunar phase, shared among several fishers. Species
observed aggregating included the families Serranidae (Epinephelus coioides and E.
lanceolatus), Lethrinidae (Lethrinus lentjan), Scombridae (Rastralliger brachysoma and R.
kanagurta) and Carangidae. As has been found in many other parts of the world, FSAs in the
Bay of Bengal are targeted by fishers. The results from this study will be used to increase
awareness among communities as well as managers and policy makers of the ecological
significance and vulnerability of reef fish spawning aggregations in order to design and
implement suitable management responses.
22.828
Marine Fisheries Management in Sierra Leone: Achievements And Challenges
Sheku SEI* 1 , Mohamed .B.D. SEISAY 2 , Heiko SEILERT 3 , Ibrahim TURAY 1
1 Statistics and Research Unit, Ministry of Fisheries and Marine Resources, Jomo Kenyatta
Road, Freetown, Sierra eone, Freetown, Sierra Leone, 2 Statistics and Research Unit, Ministry of
Fisheries and Marine Resources, Jomo Kenyatta Road, Freetown, Sierra Leone, Freetown,
Sierra Leone, 3 Gopa Consultants, Institutional Support for Fisheries Managment in Sierra
Leone, Ministry of Fisheries and Marine Resources, Jomo Kenyatta Road, Freetown, Sierra
eone, Freetown, Sierra Leone
The fisheries of Sierra Leone is classified into three subsectors: the highly mechanized export
oriented industrial marine fisheries, the labor intensive, artisanal marine fisheries, which is the
main sources of local fish supply, as well as the inland fisheries/aquaculture subsector. The
Sierra Leone policy framework sets out objectives and strategies for comprehensive
management of each of these subsectors. The legal framework for fisheries management in
Sierra Leone is the 1994 fisheries management and development act complemented by the 1995
fisheries regulations. Fisheries management measures include access limitations by licensing
(fishing effort regulations), mesh size regulations, gear restrictions, area limitations, landing,
import and export obligations, and the enforcement of fisheries regulations through fisheries
surveillance patrols and penalties for violations. These measures are based on the collection and
analysis of statistical, data from artisanal and industrial fisheries. Surplus production models are
used to estimate potential yields. Current data suggests a standing stock of nearly 300 000
metric tons, pelagic fish constituting about 90 % of the estimated biomass. Commercial
fisheries production is estimated at 130 000 metric tons, with the clupeids constituting over 75
%. The estimated maximum sustainable yield in the year 2000 was about 180 000 metric tons.
Fisheries management efforts are being enhanced by donor interventions. Major challenges are
combating illegal fishing and piracy, as well as artisanal/industrial conflict resolution.
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