Application 124771 - Ministry of Fisheries

Waikato Regional Council 

Private Bag 3038 

Waikato Mail Centre 

HAMILTON 3240 

Attn: Christin Atchinson 

Dear Christin 

Robin Britton 

PC BOX 7016 

Hamilton 3247 

Mobile 027 281 2969 

Email rbrittonOwave.co.nz 

2"" June 2012 

Re: Coromandel Marine Farms - Applications for Extensions 

Please find enclosed resource consent applications for extensions to the following 

existing marine farms in the Coromandel. 

Applicant Name Company Name Li/lease No. Consent No 

P James AD James 380 112687 

AD James 421 112701 

G James Goldridge 361 112676 

Moturoa Trust 373 112682 

Gilbert James 291 112653 

R Bronlund Seahorse Mussels Ltd 327 112663 

Seahorse Mussels Ltd 343 112667 

M James MW & RLG James 383 112698 

R Caldicutt Weka Marine Farms 363 112679 

Each application includes: 

• Covering letter 

• Assessment of Environmental Effects 

o Survey plan 

o Short Report: Cawthron 

• Lodgment fee of $500.00 per farm 

Weka Marine Farms 379 112686 

In addition one copy of a full report from Cawthron which addresses all farms 

extensions is also submitted. 

A CD including copies of all this documentation is also enclosed.

Each applicant requests that you forward a GST receipt to the applicant (or via 

myself), regarding the payment lodged. 

If there are any further queries on this please feel fi-ee to call me on 027 281 2969. 

Many thanks. 

Yours sincerely 

Robin Britton 

Resource Management/ Plarming Consultant

REPORT NO. 2134 

ASSESSMENT OF BENTHIC AND WATER COLUMN 

EFFECTS FROM INSHORE COROMANDEL 

MUSSEL FARMS

CAWTHRON INSTITUTE | REPORT NO. 2134 MAY 2012 

EXECUTIVE SUMMARY 

In August 2011, a collective of inshore mussel farmers from Coromandel approached 

Cawthron Institute (Cawthron) to provide baseline benthic assessments of effects as a part of 

their applications for 1 ha extensions to 32 mussel farms. These ‘baseline’ assessments and 

their structure are detailed in the Waikato Regional Council (WRC) Draft Coastal Plan. 

To fulfil the requirements of the Coastal Plan, a wider-scale assessment programme was 

agreed upon by WRC, Cawthron and the collective of farmers, whereby eight representative 

‘reference’ farms were selected for full benthic and water column assessments to provide an 

indication of the effects of mussel farms, and six ‘control’ sites were selected to provide a 

‘baseline’ or ‘background’ assessment of the unfarmed benthic and water column 

environments. Fieldwork was carried out between 12-16 December 2011. 

The seabed beneath and adjacent to the six control and eight reference farm sites was 

characterised and mapped using a range of sampling techniques including depth profiling, 

sediment grab sampling and video transects. Sediments were tested for total nitrogen (TN), 

total organic carbon (TOC), particle grain-size and infauna (richness, abundance and 

diversity). At all 32 mussel farm sites, sufficient sampling was undertaken to delineate the 

extent of mussel clumps around farm areas (see Appendix 7-39). 

No clear patterns in sediment particle grain-size components relating to area (north or south 

of Coromandel Harbour) or site type (’control’ versus ‘farm’) were evident (see Section 5.1). 

At the majority of sites sediments were dominated (> 50%) by fine muddy silts (< 64 μm). 

Sediment cores at the majority of sites were characterised by a fairly uniform light grey/brown 

colour and appeared well oxygenated, with no evidence of an apparent Redox Potential 

Discontinuity (aRPD) layer or sulphide odours. 

Total nitrogen was significantly higher in sediments collected from under the reference farms 

than at control sites (see Section 5.1). In general, lower average TN was found at sites 

where sediments had a greater sand component. 

Sediment organic content (total organic carbon, TOC) at the reference farms and control 

sites was different in the two different areas (north or south of Coromandel Harbour) (see 

Section 5.1). Farm sites to the north, generally had greater TOC than those to the south of 

Coromandel Harbour, while control sites had similar TOC regardless of which area they were 

in. Overall, TOC was greatest in sediments that contained the most gravel - sized particles, 

and lowest at sites with sediments that had a greater sand component. 

Dominant infauna taxa across all sites were the window shell (Theora lubrica), various 

species of polychaetes (e.g. Heteromastus filiformis, Prionospio multicristata, Prionospio 

yuriel and Sphaerosyllis sp.), brittle stars, and oligochaete worms (Section 5.2). The 

dominant epifauna taxa by abundance were Phoxocephalidae amphipods, Decapoda larvae 

(unidentified) and Melitidae amphipods. 

iii

MAY 2012 REPORT NO. 2134 | CAWTHRON INSTITUTE 

The differences in infauna communities between the reference farm and control sites were 

indicative of a mildly enriched benthic environment beneath farms resulting in greater 

abundances of opportunistic species. However, in most cases the subtle differences 

observed were in the abundance of species, rather than their presence or absence, 

suggesting that infauna communities in the wider environment are already exposed to mild 

enrichment. This conclusion was supported when the biological and physico-chemical data 

were used to calculate enrichment stage (ES), and no significant difference between the ES 

of control and farmed sites was found. 

Epibiota communities at the reference farm sites were characterised by mussels and large 

numbers of sea stars, sea cucumbers and ascidians, and were relatively diverse compared 

to the sparse epifauna observed at most control sites (see Section 5.3). Scallops and horse 

mussels were observed inshore of some reference farm and control sites, particularly on 

sand- and shell-dominated substrata. 

A snap-shot of water column properties at the reference farm and control sites using 

replicate CTD casts showed a well-mixed water column at some reference farms and control 

sites, but a thermo- and halo- cline (stratification of temperature or salinity) was observed 

between 5-10 m at several reference farm sites and control sites (Section 5.4). The greatest 

inter-site range in salinity and temperatures was observed in the top 5-10 m of the water 

column. Chlorophyll-a (chl-a) was similar between reference farms and control sites 

throughout much of the water column. Water column turbidity was similar between the 

reference farms and control sites in the top 1-2 m of the water column; but there was less 

turbidity between 3-5 m at farm sites. At depths of 5-7 m, farm sites were more turbid, but at 

depths greater than 7 m, turbidity was generally lower at farm sites. 

All of the 32 mussel farm sites and their proposed extension areas (Appendices 7-39) appear 

to have been placed away from significant inshore reef and other sensitive habitats and were 

mainly over muddy substrata. Consequently, effects to the benthic environment were 

restricted to changes in infauna and epifauna abundances, related mussel drop-off and mild 

enrichment from the farms. 

Conclusions: 

iv 

1. Our assessment of the environment beneath the reference farms in the north and 

south of Coromandel Harbour (from Wilsons Bay to Colville Bay) found differences 

in the physical and biological characteristics of benthos, when compared to control 

sites. Effects included minor enrichment and increased diversity of epibiota, and 

were equivalent to those observed beneath mussel farms elsewhere in New 

Zealand. 

2. Farm-related effects of mild enrichment, and increased abundances of infauna 

and epibiota were attributable to mussel drop-off and other farm-related deposition 

that are not necessarily negative and would be reversible over time. The


depositional effects did not extend to any reef or significant inshore rocky habitat 

at any of the 32 mussel farm sites. 

3. The top 10 m of the water column had the greatest variability in salinity and 

temperature across both reference farms and control sites, but no consistent 

patterns or differences were observed in chl-a. Reference farm sites were 

generally found to be less turbid than control sites below a depth of 7 m, which 

could be attributed to filtration of the water column by mussels. Wider-scale and 

longer-term monitoring and validated models will be necessary to provide a 

greater understanding of the contribution of aquaculture to water column 

properties in the Coromandel region. 

4. In general, the effects of mussel farms on the benthic marine environment, in 

terms of enrichment and modification, have been found to be minor (Keeley et al. 

2011), particularly when placed over primarily muddy substrata. Here we found 

that the effects to the benthic environment from Coromandel inshore mussel farms 

are similar, if not less, than in other areas of New Zealand. Therefore, providing 

the proposed additional 1 ha extensions (over and above the existing consented 

farm areas) are placed over similar substrata, the effects to the environment are 

likely to be similar to those observed in this assessment. 

v


TABLE OF CONTENTS 

1. BACKGROUND ................................................................................................................ 1 

2. AREA AQUACULTURE HISTORY ................................................................................... 3 

3. BACKGROUND TO SEABED AND WATER COLUMN EFFECTS .................................. 4 

3.1. Seabed effects ................................................................................................................................................ 4 

3.2. Water column effects ...................................................................................................................................... 6 

4. METHODS ........................................................................................................................ 7 

4.1. Characterisation and mapping of the seabed ................................................................................................. 7 

4.1.1. Site bathymetry ......................................................................................................................................... 7 

4.1.2. Sediment physical, chemical and biological properties ............................................................................. 7 

4.2. Water column sampling .................................................................................................................................. 8 

5. RESULTS ......................................................................................................................... 9 

5.1. Sediment physical and chemical properties ................................................................................................... 9 

5.2. Sediment biological properties ...................................................................................................................... 11 

5.3. Enrichment stages ........................................................................................................................................ 15 

5.4. Epibiota from video transects ....................................................................................................................... 15 

5.5. Water column properties .............................................................................................................................. 20 

6. DISCUSSION .................................................................................................................. 25 

6.1. Benthic effects .............................................................................................................................................. 25 

6.2. Water column effects .................................................................................................................................... 26 

6.3. General conclusions ..................................................................................................................................... 28 

7. REFERENCES ............................................................................................................... 30 

8. APPENDICES ................................................................................................................. 32 

LIST OF FIGURES 

Figure 1. Map showing the eight reference farm sites and the six control sites used in the wider 

assessment of benthic and water column effects. .............................................................. 2 

Figure 2. Summary of potential wider ecological effects, localised benthic effects, and water 

column effects of mussel farming on the environment. ...................................................... 4 

Figure 3. Stylised depiction of a typical enrichment gradient experienced at low flow sites, 

showing generally understood responses in commonly measured environmental 

variables. ............................................................................................................................. 5 

Figure 4. Average sediment grain-size, total nitrogen and total organic carbon for control and 

farm sites to the north and south of Coromandel Harbour. .............................................. 10 

Figure 5. Average total nitrogen and total organic carbon from reference farms and control sites 

to the north and south of Coromandel Harbour. ............................................................... 11 

Figure 6. MDS (Multidimensional scaling) plot of similarity of infauna communities between 

control and farm sites to the north and south of Coromandel Harbour............................. 13 

Figure 7. Average enrichment stages from replicate grab samples at control and reference farm 

sites. .................................................................................................................................. 15 

Figure 8. Representative images captured from video footage from control sites and reference 

farm sites. A) Sandy seabed with horse mussels, B) Sand and shell seabed with 

mussels and anemone, C) Mud seabed with horse mussel and benthic diatom mat, D) 

Mud seabed with mussels and benthic diatom mat, E) Mud seabed, F) Mud seabed 

with shell. .......................................................................................................................... 17 

vii


Figure 9. Representative images of epibiota captured from video footage from reference farm 

sites A) Mussels and sea stars, B) Sandy seabed with mussels and scallop shell, C) 

Mud seabed with solitary ascidian, D) Mussels and sea star. .......................................... 18 

Figure 10. CTD salinity and temperature data from six control sites and eight reference farm 

sites. .................................................................................................................................. 21 

Figure 11. CTD chlorophyll and turbidity data from six control sites and eight reference farm sites. 22 

Figure 12. Fluorescence in depth bins from six control sites and eight reference farm sites. ........... 23 

Figure 13. Turbidity in depth bins from six control sites and eight reference farm sites. ................... 24 

Figure 14. Depth averaged water velocities from an unvalidated model of the study area on the 

Coromandel Peninsula at various tidal states in February 2000. ..................................... 28 

LIST OF TABLES 

Table 1. Average and relative abundances of the 10 most common infauna and epifauna taxa 

collected from grab samples within six control and eight reference farm sites in 

Coromandel ....................................................................................................................... 14 

Table 2. Relative abundance of the most common epibiota observed from video transects at six 

control and eight reference farm sites in Coromandel ...................................................... 19 

LIST OF APPENDICES 

Appendix 1. GPS locations of grab samples and CTD casts in NZ Map Grid and WGS 84 from the 

eight reference farm sites and the six control sites. .......................................................... 32 

Appendix 2. Physico-chemical and biological data, and biotic indices, from grab samples at the 

eight reference farm sites and the six control sites. .......................................................... 33 

Appendix 3. Sediment core photographs from the eight reference farm sites and the six control 

sites. .................................................................................................................................. 35 

Appendix 4. Complete list of biota recorded from grab samples at reference farm sites and control 

sites. .................................................................................................................................. 38 

Appendix 5. Results of the Simper analysis for infauna abundance data from grab samples at 

reference farm sites and control sites at 35% similarity. .................................................. 42 

Appendix 6. Benthic maps for the eight reference farm sites, showing estimated extent of mussel 

shell drop-off and sediment grain-size results. ................................................................. 46 

Appendix 7. Cawthron short reports for 32 proposed inshore mussel farm extensions. ...................... 56 

viii


1. BACKGROUND 

In August 2011, a collective of inshore mussel farmers from Coromandel approached 

Cawthron Institute (Cawthron) to provide baseline benthic assessments of effects, as 

a part of their applications for 1 ha extensions to their mussel farms. These ‘baseline’ 

assessments and their structure are detailed in the Waikato Regional Council (WRC) 

Draft Coastal Plan. However, many of the farms in question had recently been issued 

with off-site and over-size notices by WRC and in most cases the extensions being 

applied for were already being farmed. Consequently, it was not possible to provide 

true ‘pre-impact’ baseline data for the proposed extensions. Following liaison with 

WRC, it was agreed that full baseline surveys for each extension would be 

unproductive and instead a rationalised approach should be used to fulfil the 

requirements of the Coastal Plan. 

To accomplish this, a wider-scale assessment programme was agreed upon by WRC, 

Cawthron and the collective of farmers, whereby eight representative ‘reference’ 

farms (Table 1) were selected for full benthic and water column assessments to 

provide an indication of the effects of mussel farms, and six ‘control’ sites were 

selected to provide a ‘baseline’ or ‘background’ assessment of the unfarmed benthic 

and water column environments. The reference farms and control sites were chosen 

to span the majority of the inshore mussel farm region along on the western side of 

the Coromandel Peninsula from Wilsons Bay to Colville Bay (Figure 1). This report 

summarises the results from this wider-scale assessment and individual farm 

extension reports are appended to this document. 

1


2 

Key 

Hauraki 

Gulf 

Firth of 

Thames 

Reference farms 

Control sites 

Motukahaua 

Island 

Other marine farms 

Moturua 

Island 

Farm 1 

Farm 3 

Farm 6 

Control 4 

Farm 8 

Motuwi 

Island 

Control 1 

Farm 7 

Control 2 

Control 6 

Wilson 

Bay 

Farm 2 

Control 3 

Control 

5 

Colville Bay 

Farm 5 

Farm 4 

Coromandel 

Harbour 

Coromandel 

Peninsula 

Sugarloaf Wharf 

Te Kouma Harbour 

Manaia Harbour 

Ü 

Farm 1 - Li 396 

Farm 2 - Li 292 

Farm 3 - Li 346 

Farm 4 - Li 296 

Farm 5 - Li 380 

Farm 6 - Li 362 

Farm 7 - Li 379 

Farm 8 - Li 344 

0 1.25 2.5 5 7.5 10 

km 

Figure 1. Map showing the eight reference farm sites (red) and the six control sites (blue) used in 

the wider assessment of benthic and water column effects.


2. AREA AQUACULTURE HISTORY 

The eastern Hauraki Gulf was one of the first areas in New Zealand to have long-line 

mussel farms. From the early 1980s, the number of inshore mussel farms along the 

Coromandel Peninsula have increased to over fifty farms that currently cover an area 

of approximately 250 ha. Most of these farms are located in a narrow coastal strip 

around the Coromandel Peninsula, with the main regions at Coromandel and Manaia 

Harbours. These areas offer sheltered waters, accessibility, favourable climate and 

good growing conditions for mussel farming. In 1999, a 1210 ha zone of mussel farms 

was set up offshore from Wilson Bay, bringing the total area of marine farms to 1500 

ha (including intertidal oyster farms). The Waikato region now produces about 20% (c. 

21,000 tonnes) of New Zealand’s green-lipped mussels, Perna canaliculus. 

3


3. BACKGROUND TO SEABED AND WATER COLUMN 

EFFECTS 

4 

The ecological effects from farming mussels and other filter-feeding bivalves on the 

benthic and wider environment have recently been reviewed in a New Zealand 

context (Figure 2, Keeley et al. 2010). Below we provide a summary of the effects of 

mussel farms on the seabed and water column, taken from Keeley et al. 2010 (with 

minor changes). 

Figure 2. Summary of potential wider ecological effects, localised benthic effects, and water 

column effects of mussel farming on the environment (from Keeley et al. 2010). 

3.1. Seabed effects 

The main ecological effects on the seabed from farming mussels and other filterfeeding 

bivalves arise from biodeposits (Giles et al. 2006) and drop-off of mussels, 

shell and associated biota (Wong & O’Shea 2011). In most instances, the severity of 

seabed effects have been assessed as low to moderate (Keeley et al. 2010). The 

effects exhibit as minor enrichment of the seabed sediments (organic content 

increases of up to ~7.5%) (Hartstein & Stevens 2005), increased build-up of shell litter 

directly beneath the site and, in some instances, increased aggregations of seastars 

and other epifauna taxa (Kaspar et al. 1985). Sediment enrichment, in-turn, affects the 

composition of sediment dwelling biota with productivity generally enhanced (i.e. 

some smaller species, like polychaete worms, become more prolific). Changes to the 

surface dwelling biota (e.g. seastars) have been documented but are difficult to 

quantify and vary significantly between sites (Kaspar et al. 1985). Seabed effects are 

most pronounced directly beneath farm sites, reduce rapidly with distance, and are


usually difficult to detect within 20-50 m away. A similar conclusion was reached in a 

recent study under mussel farms in the Hauraki Gulf (Wong & O’Shea 2011), who 

suggested that the extent of mussel clumps on the seabed was the best indicator of 

the extent of benthic effects. The most important factors influencing the area and 

magnitude of effects surrounding mussel farms are water depth and current speeds 

(Hartstein & Stevens 2005); hence severity of effects is very much site-specific and 

effects are minimised by locating farms in well-flushed areas, where species and 

habitats of special value are not present. 

Enrichment from farm-derived biodeposits is the primary cause of seabed effects in 

soft-sediment habitats and the type of effects are reasonably well described (Keeley 

et al. 2010), as such they can be placed on an enrichment gradient ranging from 

natural to azoic (Figure 3). Using biological and physico-chemical data from benthic 

enrichment studies under finfish and mussel farms throughout New Zealand, the 

gradient has been described numerically with enrichment stages (ES) 1 to 7 

(Figure 3). This method can now be assigned to benthic grab samples to allow 

comparison of enrichment effects from sites around New Zealand (Keeley et al. 2012, 

Keeley et al. In press). 

Figure 3. Stylised depiction of a typical enrichment gradient experienced at low flow sites, showing 

generally understood responses in commonly measured environmental variables 

(species richness, infauna abundance, sediment organic content and sulfides and 

Redox). Apparent Redox Potential Discontinuity depth (aRPD) and prevalence of bacteria 

(Beggiatoa spp.) mats and methane/H2S out-gassing also indicated. The gradient spans 

from natural or pristine conditions on the right (ES = 1) to highly enriched azoic conditions 

on the left (ES = 7). 

5


6 

3.2. Water column effects 

Effects of mussel cultivation on the water column are less well defined than for the 

seabed, because water column characteristics are more dynamic and inherently 

harder to quantify. The physical presence of farms can alter and reduce current 

speeds, which affects water residence times and has implications for associated 

biological processes. Farm structures can also attenuate short-period waves (Plew et 

al. 2005), which can affect inshore ecology, but these issues are not considered 

significant at the present scale of development in New Zealand. Bivalves and other 

associated fauna release dissolved nitrogen (e.g. ammonium) directly into the water 

column, which can cause localised enrichment and stimulate phytoplankton growth. 

Toxic microalga blooms may lead to ecological or health problems, but there is no 

evidence of this being exacerbated by mussel farming in New Zealand waters. 

Filtration pressure by mussels is sufficient to potentially alter the composition of the 

phytoplankton and zooplankton/mesoplankton communities through feeding, but the 

extent to which this occurs and its ecological consequences are poorly understood. 

Despite the recognised knowledge gaps, the fact that no significant water column 

related issues have been documented, suggests that effects associated with 

traditional inshore farming practices are minor (Keeley et al. 2010).


4. METHODS 

4.1. Characterisation and mapping of the seabed 

The seabed beneath and adjacent to the reference farms and control sites was 

characterised and mapped using a range of sampling techniques including depth 

profiling, sediment grab sampling and video transects (see Appendix 1 for sampling 

coordinates). Sufficient sampling was undertaken to delineate the extent of mussel 

clumps around farm areas. The fieldwork was carried out over four days from 12-16 

December 2011. 

4.1.1. Site bathymetry 

Depth profiling at the reference farm sites was calculated from digitised bathymetric 

charts and in-situ measurements to assist in the characterisation the seabed. In-situ 

measurements were taken using continuous depth readings from a Garmin F100 

depth sounder within and adjacent to the reference farm areas, and were sent to a PC 

via a RS232 serial output. The PC simultaneously collected separate RS232 serial 

output of latitude and longitude from a GPS, and both data streams were incorporated 

using communications software. In-situ depth measurements were standardised to 

chart datum and plotted using Surfer v7 surface mapping software. The 2-D 

graduated colour contour map was gridded using the natural neighbour method 

(Sibson 1981). 

4.1.2. Sediment physical, chemical and biological properties 

Sediment grab samples were collected using a 0.01 m 2 van Veen grab sampler from 

three sampling stations within the eight reference farm sites and six control sites. The 

following sub-samples were collected from each grab sample to characterise the 

physical, chemical and biological properties of the sediments: 

Sediment core samples: A 63 mm diameter core was photographed and the 

top 25 mm was collected for analyses of sediment grain-size and total organic 

carbon (TOC) and total nitrogen (TN). Grain-size was determined gravimetrically 

after separation of fractions by wet sieving and drying at 105 ºC, for gravel 

(≥2 mm), sand (≥63 μm -


8 

Macrofaunal core samples: A 130 mm diameter core, approximately 100 mm 

deep was gently sieved through a 0.5 mm mesh and animals retained were 

preserved with ethanol and 10% glyoxal in sea water, and transported back to 

Cawthron for identification and counting. Infauna data were analysed to 

ascertain levels of abundance (taxa density) and taxa richness and diversity. The 

infaunal assemblages were contrasted using non-metric multidimensional 

scaling or MDS (Kruskal & Wish 1978) and ordination and cluster diagrams 

based on Bray-Curtis similarities (Clarke & Warwick 1994). Abundance data 

were fourth-root transformed to de-emphasise the influence of the dominant 

species (by abundance). The major taxa contributing to the similarities of each 

group (areas) were identified using analysis of similarities (SIMPER; Clarke & 

Warwick 1994; Clarke & Gorley 2001). All multivariate analyses were performed 

with PRIMER v6 software. 

Enrichment stages: The quantitative biological and physico-chemical data from 

each grab sample were used to assign an enrichment stage (ES) (Figure 3). ES, 

from 1 being ‘pristine/natural’ to 7 being ‘azoic/anoxic’, is quantitatively 

determined from previously derived empirical relationships with multiple biotic 

and physico-chemical indicators (for further details see Keeley et al. In press). 

4.2. Water column sampling 

A snap-shot in time of the water column conditions at the six control and eight 

reference farm sites was provided by three replicate casts of a Seabird CTD at each 

site. The CTD measured, salinity, temperature, chl-a and clarity (turbidity) throughout 

the water column.


5. RESULTS 

5.1. Sediment physical and chemical properties 

Sediments sampled from within the eight reference farms and six control sites 

contained varying amounts of silt and clay (< 63 µm), sand (< 2 mm and > 63 µm) and 

gravel-sized (> 2 mm) components (Figure 4, see Appendix 2 for raw data). No clear 

patterns in sediment particle grain-size components relating to area (north or south of 

Coromandel Harbour) or site type (‘control’ versus ‘farm’) were evident. The majority 

of sites within the region had only small gravel components, and only four sites had an 

average gravel component of 20% or more (Control sites 1 and 4 and Farm sites 1 

and 6). A different suite of sites had sand components greater than 30% of their total 

dry weight (Control sites 2 and 4 and Farm sites 2, 6 and 7), and it was these same 

sites that had silt components that were less than 50% of their total dry weight. At all 

other sites, the majority of the sediments (> 50%) were comprised of fine muddy silts 

(< 63 um). 

Observations made from video footage (see Section 5.4), were consistent with these 

results, where fine silt/mud was the most common substratum, even at control sites. 

Sand/shell dominated substrata were only observed at a small number of control and 

farm sites. Sediment cores at the majority of reference farm and control sites were 

characterised by a fairly uniform light grey/brown colour and appeared well 

oxygenated, with poorly defined aRPD layers that ranged between 40 and 60 mm 

below the seafloor (see Appendix 2 for images). No sulphide odours were detected. 

Total nitrogen (TN) was significantly higher in sediments collected from under farms 

than at control sites (site type, F1, 38 = 7.98, p


Figure 4. Average sediment grain-size (percentage of dry weight), total nitrogen (TN, mg kg -1 dry 

weight) and total organic carbon (TOC, percentage of dry weight) for control and farm 

sites to the north and south of Coromandel Harbour. 

10


Total Nitrogen (+ 1s.e.) 

Total Organic Carbon (± 1s.e.) 

2500 

2000 

1500 

1000 

500 

0 

3 

2.5 

2 

1.5 

1 

0.5 

0 

North 

South 

Reference Farms Control Sites 

North 

South 

Reference Farms Control Sites 

Site Type 

Figure 5. Average total nitrogen (TN, mg kg -1 dry weight, ± 1 s.e.) and total organic carbon (TOC, 

percentage of dry weight, ± 1 s.e.) from reference farms and control sites to the north and 

south of Coromandel Harbour. 

5.2. Sediment biological properties 

Sediments sampled from the control sites contained infaunal communities 

representative of those commonly found in natural sediments throughout the Hauraki 

Gulf (Wong & O’Shea 2011), and are therefore considered indicative of background 

conditions. Two of the grabs at Control site 2 were characterised by low infauna taxa 

richness and taxa abundance (Table 1). A total of 110 macro-benthic taxa were 

recorded across all samples, comprised of 64 infauna species and 66 epifauna 

species. Average macro-benthic taxa richness (total infauna and epifauna) per sample 

was similar between control and farm sites, ranging from 10 to 33 at control sites, and 

16 to 28 taxa at reference farm sites. Sample evenness, from Pielou’s evenness 

11


12 

index, was also similar between farm and reference sites, with the most even samples 

(i.e. closest to 1 in the index) being Control site 6 (0.97) and Farm site 1 (0.89). 

Species diversity was calculated using the Shannon Wiener diversity index, and 

averaged between 2.15 and 2.9 at Control sites (3 and 1 respectively) and between 

1.93 and 2.89 at Farm sites (4 and 1). A complete list of biological indices can be 

found in Appendix 2 and a complete taxa list can be found in Appendix 3. 

The dominant infauna taxa across all sites were the window shell (Theora lubrica), 

various species of polychaetes (e.g. Heteromastus filiformis, Prionospio multicristata, 

Prionospio yuriel and Sphaerosyllis sp.), brittle stars, and oligochaete worms (Table 

1). The dominant epifauna taxa by abundance were Phoxocephalidae amphipods, 

Decapoda larvae (unidentified), Cumaceans and Melitidae amphipods. 

Patterns in infaunal community composition were further explored using multivariate 

statistical techniques (Figure 6, see Appendix 1 for Simper analysis). In addition to 

being distinguished by the low total abundance and taxa richness, multivariate 

analysis showed the infaunal community at Control site 2 was different to the other 

stations; due mainly to a greater abundance of the nut clam, Nucula gallinacea and 

Phyllodocidae polychaetes, and the near absence of polychaete worms like 

Sigalionidae sp., Cossura consimilis and Prionospio yuriel. This group was also 

differentiated by lower abundances of a number of invasive bivalve (Theora lubrica), 

the capitellid worm (Heteromastus filiformis) and the polychaete worm (Sphaerosyllis 

sp). 

The infauna communities from the control and farm grab samples were generally 

separated at the 35% level of similarity (Figure 3). The majority of samples from the 

control sites and individual grabs from four farm sites (Li 292, 362, 379, and 396), 

were differentiated by greater numbers of polychaetes (Neonesidea sp., Sigalionidae, 

Cossura consimilis and Aglaophamus species), but also by lower abundances of most 

taxa found in the majority of farm samples. Grab samples from farm sites and 

individual grabs from Control site 1, 4 and 6, were grouped by higher abundances of 

polychaete worms including Prionospio multicristata, Prionospio yuriel, and the 

capitellid worm (Heteromastus filiformis), but also had greater numbers of the invasive 

marine bivalve (Theora lubrica). 

The differences in infauna communities found between farm and control sites are 

indicative of a mildly enriched benthic environment beneath farms resulting in greater 

abundances of opportunistic species. However, in most cases the subtle differences 

observed were in the abundance of species, rather than their presence or absence. 

This suggests that infauna communities in the wider environment are already exposed 

to mild enrichment through natural sedimentation processes.


Control 2 

Control 2 

Transform: Fourth root 

Resemblance: S17 Bray Curtis similarity 

Control 2Control 

6 

Control 5 

Farm 2 Farm 1 

Control 6 

Control 1 

Control 4 

Farm 2 Control 

Control 

1 

1 

Control 4 

Farm 1 Farm 4 

Control 4 

Farm Farm 1 6 Farm 7 Control 5 

Farm 3 Control 3 

Farm 6 Farm 3 Farm 7 

Farm 8 Farm 8 Control 3 

Farm 

Farm 

3 

7 

Farm 4 

Farm 5 

Control 5 

Farm 5 Farm 2 

Farm 6 

Farm 8 Control 3 

Farm 5 

Farm 4 

Control 6 

2D Stress: 0.22 

Grouping 

Control North 

Control South 

Farm North 

Farm South 

Similarity 

35 

Figure 6. MDS (Multidimensional scaling) plot of similarity of infauna communities between control 

and farm sites to the north and south of Coromandel Harbour. Circles in the MDS plot 

show 35% similarity (see Appendix 1 for full Simper analysis). 

The epifauna communities from grab samples were similar at farm and control sites 

(Table 1) and were also indicative of a mildly enriched benthic environment. 

Opportunistic species such as amphipods, cumaceans and crabs were present at 

most sites in similar abundances. The slipper shell snail (Sigapatella novaezelandiae), 

however, was only found at the most northern control site (Con 1), while the anemone 

(Anthopleura aureoradiata), and the mussel pea crab (Pinnotheres novaezelandiae), 

were only found on mussel shell deposits beneath reference farm sites. 

13


Table 1. Average and relative abundances (%) of the 10 most common infauna and epifauna taxa collected from grab samples within six control and eight 

reference farm sites in Coromandel (See Appendix 4 for full species list). 

Con Con Con Con Con Con 

Rel. 

1 2 3 4 5 6 

Av. abund. 

Taxa 

INFAUNA 

Common Name Nth Nth Nth Sth Sth Sth Farm1 Farm2 Farm3 Farm4 Farm5 Farm6 Farm7 Farm8 abund. (%) 

Heteromastus filiformis Polychaete worm 13 1 2 14 3 1 2 41 4 12 8 5 3 3 10 13 

Prionospio multicristata Polychaete worm 14 10 15 8 3 4 4 76 1 1 15 11 

Theora lubrica Window Shell 1 1 2 4 4 4 7 15 18 6 3 16 11 6 7 9 

Prionospio yuriel Polychaete worm 3 2 3 1 1 3 3 22 18 4 2 10 8 7 9 

Sphaerosyllis sp. Polychaete worm 23 8 1 6 24 2 4 1 5 2 9 7 

Ophiuroidea Brittle stars 12 1 2 3 4 10 5 3 2 5 4 

Armandia maculata Polychaete worm 4 1 8 6 7 2 2 16 3 3 6 4 

Sigalionidae Polychaete worm 2 1 2 2 3 3 3 4 5 3 3 2 5 2 3 4 

Oligochaeta Oligochaete worms 1 1 5 3 4 1 2 18 5 3 

Cirratulidae 

EPIFAUNA 

Polychaete worm 2 2 2 1 1 3 15 2 3 4 1 6 2 3 3 

Phoxocephalidae Amphipod (family) 3 2 4 12 14 38 16 25 2 108 3 5 21 33 

Decapoda (larvae unid.) UI Crab Larvae 99 1 66 13 

Cumacea Cumaceans 4 2 1 2 2 2 2 4 3 1 1 42 3 2 6 9 

Melitidae Amphipod 19 1 1 38 1 2 2 2 3 3 10 2 5 7 

Sigapatella novaezelandiae Slipper shell snail 57 57 4 

Petrolisthes elongatus Half crab 1 1 7 3 1 2 1 1 9 3 3 

Aoridae Amphipod (Family) 4 3 3 1 14 2 4 2 

Anthopleura aureoradiata Anemone 3 2 16 9 2 

Pinnotheres novaezelandiae Mussel Pea Crab 14 14 2 

Philine auriformis White Sea Slug 3 2 1 2 2 1 2 3 1 2 2 

Average # of Individuals 151 22 21 95 22 16 108 223 105 77 81 228 65 50 

Average # of Taxa 33 16 11 24 12 10 28 27 23 16 23 28 20 16 

Pielou’s Evenness 0.89 0.95 0.92 0.73 0.94 0.97 0.89 0.75 0.79 0.73 0.88 0.77 0.88 0.80 

Shannon Wiener Diversity 2.90 2.61 2.15 2.27 2.28 2.22 2.89 2.21 2.46 1.93 2.68 2.36 2.63 2.20 

14


5.3. Enrichment stages 

The biological and physico-chemical data from each grab sample were used to 

assess and compare the relative enrichment stage (ES) of each grab sample 

(Figure 7). No significant difference between the ES of grab samples at control and 

reference farm sites (F1,40 = 0.12, p > 0.05) was observed. All sites, except Control site 

2, were mildy enriched regardless of type (‘control’ or ‘farm’), with average ES scores 

of 2.03 (s.e. ± 0.85) across all control sites and 2.07 (s.e. ± 0.74) at reference farm 

site. 

Enrichment Stage (ES ± 1 s.e.) 

3.5 

3 

2.5 

2 

1.5 

1 

0.5 

0 

Con 1 Con 2 Con 3 Con 4 Con 5 Con 6 Farm 

1 

Figure 7. Average enrichment stages (ES) from replicate grab samples at control and reference 

farm sites (see Appendix 2 for raw data used to calculate ES). 

5.4. Epibiota from video transects 

Video transects were used to determine the dominant substrata, the extent of mussel 

shell drop-off and the characteristic epibiota at each site (Table 2, Figures 8 and 9) 

Dense mussel shell drop-off was found to extend no more than 25-40 m from the farm 

edge of all reference farms (see maps in Appendix 6), but sparse clumps of mussels 

were observed out to 100 m at some sites, possibly due to the repositioning of farms 

over time. Epifauna species associated with mussel drop-off, and the food and solid 

substratum it provides, were common at farm sites (Figure 8, Table 2). A variety of 

sessile organisms were observed living on mussel shell beneath farms (Figure 9 A-D), 

including solitary ascidians (Pyura pachydermatina and the invasive Styela clava), 

bryozoans (including Watersipora cucullata and Bugula sp.), finger and mat forming 

sponges, bivalves, calcareous polychaetes, small feather hydroids (unknown species) 

and seaweeds (including Codium sp.). Mobile fauna observed beneath farm sites 

included fish (mainly leatherjackets, Parika scaber, and spotty wrasse Notolabrus 

Farm 

2 

Farm 

3 

Farm 

4 

Farm 

5 

Farm 

6 

Farm 

7 

Farm 

8 

15


16 

celidotus), sea stars (Coscinasterias muricata, Patiriella regularis and Astrostole 

scabra), crustaceans (particularly crabs like the pillbox crab, Halicarcinus 

innominatus; the half crab, Petrolisthes novaezelandiae; and the masking crab 

Notomithrax minor), sea urchins, and other echinoderms (like the sea cucumber, 

Stichopus mollis). 

Despite having the greatest organic content in benthic sediments (Figure 4), Farm site 

1 and its surrounding area had the highest diversity of epibiota, with abundant Steyla 

clava (~41), finger sponges (Callyspongia spp.) and horse mussels (Atrina 

zealandica, abundance estimated to be 0.52 m -2 ). 

Consistent with the results of the sediment samples, a mud/silt substratum was the 

most common substratum observed across reference farm and control sites (Figure 8 

C- E). A shell/sand substratum was observed only at one control site (Con 1, Figure 

8A) and at one farm site (Farm 1, Figure 8B). Horse mussels were most commonly 

observed on substrata with a greater sand content, both beneath reference farms and 

at control sites. They were most common in a small patch in one transect at Con 1, 

where 45 were observed in a 20 m transect. An orange benthic diatom film was 

common at reference farm and control sites, particularly on shallower silt/mud habitats 

(Figure 8C and 8D).


A) B) 

C) D) 

E) F) 

Figure 8. Representative images captured from video footage from control sites (left column) and 

reference farm sites (right). A) Sandy seabed with horse mussels, B) Sand and shell 

seabed with mussels and anemone, C) Mud seabed with horse mussel and benthic 

diatom mat, D) ) Mud seabed with mussels and benthic diatom mat, E) Mud seabed, F) 

Mud seabed with shell. 

17


Figure 9. Representative images of epibiota captured from video footage from reference farm sites 

A) Mussels and sea stars, B) Sandy seabed with mussels and scallop shell, C) Mud 

seabed with solitary ascidian (Styela clava), D) Mussels and sea star. 

18 

A) B) 

C) D)


Table 2. Relative abundance of the most common epibiota observed from video transects at six control and eight reference farm sites in Coromandel 

(Abundance = A (> 20 per transect), Common = C (8-20 per transect), Occasional = O (3-7 per transect), Rare = R (1-2 per transect), 

Not observed = Blank). 

Con Con Con 

Con 1 Con 2 Con 3 4 5 6 

Taxa 

EPIFAUNA 

Common Name 

Nth Nth Nth Sth Sth Sth Farm1 Farm2 Farm3 Farm4 Farm5 Farm6 Farm7 Farm8 

Perna canaliculus Greenlipped mussel A A A O-A A A A A 

Coscinasterias muricata 11 arm seastars O O O O O O C-A 

Patiriella regularis Cushion star O O-C R O-C C R O O-A O-C O-C O O-C 

Stichopus mollis Sea cucumber O O O O O O R 

Styela clava Solitary ascidian O R C-A C O-C O R R 

Hydroida Small feather hydroid O O A A A A A A A A 

Pecten novaezealandiae Scallop R R R 

Atrina zealandica Horse mussel A C R O O O R 

Callyspongia sp. Finger sponge R 

Actinothoe albocincta White striped anemone R R R R 

EPIFLORA 

Benthic Diatom Mat Brown benthic film C C C C C C C C C C-A A C R C 

Codium sp. Green alga R 

Rhodophyta spp. Red algae O O O 

Carpophyllum sp. Brown alga R 

19


20 

5.5. Water column properties 

A snap-shot of water column properties at the reference farm and control sites using 

replicate CTD casts showed that the water column was well mixed at some reference 

farm and control sites, but that a weak thermo- and halo- cline (stratification of 

temperature or salinity) was present between 5-10 m at several sites (Figure 10). The 

greatest range in salinity and temperatures was observed in the top 5-10 m of the 

water column. 

The range in chl-a, measured as fluorescence, was similar between control and farm 

sites throughout much of the water column (Figures 11 and 12). Chl-a concentrations 

were centred on 0.1 µg/L throughout much of the water column, but were significantly 

higher at reference farm sites than control sites between 4-11 m depth (Figure 12). 

Water column turbidity (as Formazin Turbidity Units, FTU) was similar between farm 

and control sites in the top 3 m of the water column (Figure 11), but between 3-5 m 

farm sites were less turbid; and below 12 m, farm sites were more turbid. This could 

be attributed to filtration of the upper water column by mussels, and release of pseudo 

faeces toward the lower water column. 

In general, the top 10 m of the water column had the greatest variability in salinity and 

temperature, but no consistent patterns or differences were observed in chl-a. 

Wider-scale and longer-term monitoring and validated models will be necessary to 

provide a greater understanding of the contribution of aquaculture to water column 

properties in the Coromandel region.


Control Sites (n = 6) Reference Farms (n = 8) 

Figure 10. CTD salinity and temperature data from six control sites (left column) and eight reference 

farm sites (right column). Thick lines are smoothed averages and colours denote different 

sites. 

21


Figure 11. CTD chlorophyll and turbidity data from six control sites (left column) and eight reference 

farm sites (right column). Thick lines are smoothed averages and colours denote different 

sites. 

22 

Control Sites (n = 6) Reference Farms (n = 8)


Figure 12. Fluorescence (Chl-a - µg/L) in depth bins from six control sites (red) and eight reference 

farm sites (blue). Tested using Wilcoxon signed-rank test of 1–5 m depth bins. 

Significance (e.g. p < 0.05) and level are denoted by the font size. Direction of difference 

is denoted by font colour (Blue = Farm is higher, Red = Control is higher). 

23


Figure 13. Turbidity in depth bins from six control sites (red) and eight reference farm sites (blue). 

Tested using Wilcoxon signed-rank test of 1–5 m depth bins. Significance (e.g. p < 0.05) 

and level are denoted by the font size. Direction of difference is denoted by font colour 

(Blue = Farm is more turbid, Red = Control is more turbid). 

24


6. DISCUSSION 

6.1. Benthic effects 

The effects of the reference farm sites on the benthic environment were consistent 

with those observed beneath mussel farming throughout New Zealand (e.g. Kaspar et 

al. 1985, Hartstein & Stevens 2005, Giles et al. 2006, Keeley et al. 2010, Wong & 

O’Shea 2011). 

The physico-chemical effects beneath reference mussel farms included slight 

increases in TOC and TN compared to control sites, but the composition of sediment 

was similar. Increases in TOC were not always evident, however, and were only 

observed between reference farms and control sites to the north of Coromandel 

Harbour. Interestingly, the average TOC recorded across the reference farms (2.1%, 

s.e. = 0.3) was considerably lower than levels observed under similar farms in the 

Marlborough Sounds, which regularly exceed 10% in sheltered areas (Hartstein & 

Stevens 2005). Average levels of TN (0.2%) were similar to those observed 

elsewhere in the Firth of Thames (Giles & Pilditch 2006), but considerably lower than 

those observed beneath mussel farms elsewhere in New Zealand, which can exceed 

1% (Hatcher et al. 1994). Therefore, either the majority of reference farm sites in this 

study were in relatively high flow areas, where organic wastes are dispersed rather 

than accumulating beneath the farms, or the inshore mussel farming in the 

Coromandel is less intensive than in the other areas (e.g. Marlborough Sounds). 

Infaunal community compositions at reference farms and control sites were broadly 

similar but farm sites generally had greater abundances of each taxa type. Most of the 

infauna communities were characteristic of those found in mildly enriched sediments 

observed elsewhere in the Hauraki Gulf (Wong & O’Shea 2011), possibly due to wider 

scale enrichment occurring in the environment. This conclusion was supported by 

similar enrichment stages (ES) of grab samples from control and reference farm sites, 

with samples ranging from natural to mild enrichment (ES 1.7 – 2.8 in Figure 3). 

The epibenthic communities and the extent of mussel shell drop-off at the reference 

farm sites were typical of those observed under mussel farms elsewhere in the 

Hauraki Gulf (Wong & O’Shea 2011) and in the Marlborough Sounds (Kaspar et al. 

1985, Keeley et al. 2010). Shell material extended no more than 50 m from farms and 

formed a layer approximately 10 cm deep over most of the reference farm sites. This 

shell-covered substratum was characterised by a greater diversity and abundance of 

epibiota than observed at control sites. 

The ecological effects of biodeposition from mussel farms depend on the level of shell 

deposition and enrichment from biodeposits, which will vary according to site-specific 

characteristics such as water currents, water depth and farm management practices 

(Forrest 1995). The existing substratum type also plays a major role in determining 

the level of benthic effects (Giles et al. 2006). In mud/silt dominated areas, organic 

25


26 

enrichment, together with the accumulation of debris beneath coastal mussel farms, 

increases both the food available for scavengers and habitat heterogeneity. This in 

turn can lead to significant increases in the diversity of infauna and epibiota (Inglis et 

al. 2000, Wong & O’Shea 2011). However, in shell- and sand-dominated benthic 

habitats, shifts in epibiota feeding and living on mussels and changes to enrichment 

tolerant infauna taxa can occur (Keeley et al. 2010). 

Clumps of mussels beneath the reference farm sites had been colonised by a range 

of organisms and provided a reef-like habitat for a variety of small fishes and mobile 

fauna. Elsewhere, biodeposits beneath mussel farms have been are known to attract 

large numbers of predatory fish, seastars, crabs, sea urchins and other echinoderms 

(Mattsson & Lindén 1983, Kaspar et al. 1985, Cole & Grange 1996). Furthermore, 

exclusion of trawling by the farm infrastructure also means that species which are 

regularly harvested or damaged by trawling in open areas of seabed, such as scallops 

(Pecten novaezelandiae) and horse mussels (Atrina zealandica), are occasionally 

abundant beneath the farms. The extent to which protection for these species is 

occurring beneath Coromandel mussel farms however is unknown; scallops were rare 

at all sites and occasional beds of horse mussels were observed beneath three 

reference farm sites and at four control sites. 

In general, mussel farming is unlikely to result in irreversible ecological effects 

(Forrest 1995, Keeley et al. 2010). Farms placed over mud / silt habitat, as were the 

majority of farm sites in this study, would likely return to pre-farm conditions within one 

to two years of farm removal. However, this would depend on the level of shell cover 

at each site. In extreme cases, banks of sediment and shell material up to 2 m high 

have been observed beneath Coromandel mussel farms (e.g. Coffey 2001), but the 

accumulation and extent of shell material depends on processes such as water 

movement and bioturbation which tends to disperse and modify deposited materials 

(Morrisey et al. 2000). Overall, the enrichment effects of inshore mussel farms on the 

benthic environment in the Coromandel were minor; while shell deposition and related 

effects on diversity and abundance of epibiota, while considerable, were not 

necessarily negative (Keeley et al. 2010). 

6.2. Water column effects 

The water column properties measured at reference farm sites and control sites were 

broadly similar and no clear patterns in differences were observed. Water column 

turbidity in the top 1-2 m of the water column was similar between farm and control 

sites, but farm sites were less turbid between 3-5 m and below 7 m depth. This lower 

turbidity may be attributed to the filtering effect of the mussels on the farm droppers, 

but this effect will depend greatly on the state of the tide and the water velocities at 

each site, which are known to influence the residence time of water passing through 

mussel farms (Plew 2011).


Unless they are used to calibrate ongoing wider-scale monitoring efforts (Inglis et al. 

2000), it is generally considered that, due to significant temporal and spatial variability 

in water column properties, one-off synoptic samples are of little benefit to 

understanding the effects of aquaculture on the environment. In future, the synoptic 

data collected as part of this study may be used to validate wider scale water column 

modelling efforts. For example, an unvalidated model (courtesy of MetOcean 

Solutions Limited), shows depth averaged velocities across the study area and 

potential processes affecting mixing and water characteristics during incoming and 

outgoing tides (Figure 12). Peak velocities are estimated at in the main channel areas 

and inshore of small island groups to the north of Coromandel Harbour (red arrows 

Figure 12). In conjunction with the data collected here, future, long term and widerscale 

monitoring could be used to validate such models and assist in detecting widerscale 

and longer term trends in water column properties. 

27


28 

Incoming Tide 

High Tide 

Outgoing Tide 

Low Tide 

Figure 14. Depth averaged water velocities (colour scale in m s -1 ) from an unvalidated model of the 

study area on the Coromandel Peninsula at various tidal states in February 2000 

(Courtesy of MetOcean Solutions Ltd.). Red arrows show peak flow areas behind islands to 

the North of Coromandel Harbour. 

6.3. General conclusions 

In general, the effects of mussel farms on the benthic marine environment, in terms of 

enrichment and modification, have been found to be minor (Keeley et al. 2011), 

particularly when placed over primarily muddy substrata. Here we found that the 

effects to the benthic environment from Coromandel inshore mussel farms are similar, 

if not less, than in other areas of New Zealand. Therefore, providing the proposed 

additional 1 ha extensions (over and above the existing consented farm areas) are


placed over similar substrata, the effects to the environment are likely to be similar to 

those observed in this assessment. 

All of the 32 mussel farm sites assessed in this study (Appendices 7-39) had been 

placed away from significant inshore reef and other sensitive habitats, and were 

mainly over muddy substrata. Consequently, effects to the benthic environment were 

restricted to changes in infauna and epifauna abundances related to mussel drop-off 

and mild enrichment from farm biodeposits. 

Conclusions: 

1. Our assessment of the environment beneath reference farm sites in the 

Coromandel found differences in the physical and biological characteristics of 

benthos when compared to control sites. Effects included minor enrichment and 

increased diversity of epibiota, and were equivalent to those observed beneath 

mussel farms elsewhere in New Zealand. 

2. Farm-related effects of mild enrichment and increased abundances of infauna and 

epibiota were attributable to mussel drop-off and other farm-related deposition that 

are not necessarily negative and would be reversible over time. The depositional 

effects did not extend to any reef or significant inshore rocky habitat at any of the 

32 mussel farm sites. 

3. The top 10 m of the water column had the greatest variability in salinity and 

temperature across both reference farm and control sites, but no consistent 

patterns or differences were observed in chl–a. Reference farm sites were 

generally found to be less turbid than control sites below a depth of 7 m, which 

could be attributed to filtration of the water column by mussels. Wider-scale and 

longer-term monitoring and validated models will be necessary to provide a 

greater understanding of the contribution of aquaculture to water column 

properties in the Coromandel region. 

29


7. REFERENCES 

30 

Coffey BT 2001. Coromandel Mussel Farmers Association marine farm at the mouth 

of Coromandel Harbour: Biological aspects of an assessment of environmental 

effects. Report prepared for Coromandel Marine Farmers’ Association. 

OoS:BAEE: CMFA / MFP 364. 26p. 

Cole RG, Grange KR 1996. Under the mussel farm. Seafood New Zealand 

November: 25-26. 

Giles H, Pilditch C, Bell DG 2006. Sedimentation from mussel (Perna canaliculus) 

culture in the Firth of Thames, New Zealand: Impacts on sediment oxygen and 

nutrient fluxes. Aquaculture 261:125-140. 

Hartstein ND, Stevens CL 2005. Deposition beneath long-line mussel farms. 

Aquaculture Engineering 33:192-213. 

Hatcher A, Grant J, Schofield B 1994. Effects of suspended mussel culture (Mytilus 

spp.) on sedimentation, benthic respiration and sediment nutrient dynamics in 

a coastal bay. Marine Ecology Progress Series 115:219-235. 

Inglis GJ, Hayden BJ, Ross AH. 2000. An overview of factors affecting the carrying 

capacity of coastal embayments for mussel culture. Prepared for the Ministry of 

the Environment. NIWA Client Report: CHC00/69. 38p. 

Kaspar HF, Gillespie, PA, Boyer IC, MacKenzie AL. 1985. Effects of mussel 

aquaculture on the nitrogen cycle and benthic communities in Kenepuru 

Sound, Marlborough Sounds, New Zealand. Marine Biology 85:127-136. 

Keeley N, Forrest B, Hopkins G, Gillespie P, Clement D, Webb S, Knight B, Gardner J 

2010. Review of the Ecological Effects of Farming Shellfish and Other Nonfinfish 

Species in New Zealand. Prepared for the Ministry of Fisheries. 

Cawthron Report No. 1476. 144 p. plus appendices. 

Keeley N, MacLeod C, Forrest B 2012. Combining best professional judgement and 

quantile regression splines to improve characterisation of macrofaunal 

responses to enrichment. Ecological Indicators 12:154-166. 

Mattsson J, Lindén O 1983. Benthic macrofauna succession under mussels, Mytilus 

edulis L. (Bivalvia), cultured on hanging long-lines. Sarsia 68:97-102. 

Morrisey DJ, Gibbs MM, Pickmere SE, Cole RG 2000. Predicting impacts and 

recovery of marine-farm sites in Stewart Island, New Zealand, from the 

Findlay-Watling model. Aquaculture 185:257-271. 

Plew DR, Stevens CL, Spigel RH, Hartstein ND 2005. Hydrodynamic implications of 

large offshore mussel farms. IEEE Journal of Oceanic Engineering 30:95-108. 

Plew DR 2011. Depth-Averaged Drag Coefficient for Modeling Flow through 

Suspended Canopies. Journal of Hydraulic Engineering-Asce 137:234-247.


Wong KLC, O’Shea S 2011. The effects of a mussel farm on benthic macrofaunal 

communities in Hauraki Gulf, New Zealand. New Zealand Journal of Marine 

and Freshwater Research 45(2):187-212. 

31


8. APPENDICES 

Appendix 1. GPS locations of grab samples and CTD casts in NZ Map Grid and WGS 84 

from the eight reference farm sites and the six control sites. 

Site Grab NZMG_N NZMG_E WGS84_LAT WGS84_Long 

Control1 1 6499671.211 2725200.834 36 40 42.79223 S 175 24 11.05599 E 

Control1 2 6499685.884 2725288.198 36 40 42.23916 S 175 24 14.55716 E 

Control1 3 6499678.819 2725120.952 36 40 42.61613 S 175 24 07.83157 E 

Control2 1 6495098.042 2727643.990 36 43 08.91961 S 175 25 54.49151 E 

Control2 2 6495114.782 2727782.051 36 43 08.25332 S 175 26 00.03418 E 

Control2 3 6494857.566 2727740.597 36 43 16.63143 S 175 25 58.65005 E 

Control3 1 6489107.059 2728750.223 36 46 22.20408 S 175 26 45.73981 E 

Control3 2 6489125.002 2728843.246 36 46 21.53856 S 175 26 49.46947 E 

Control3 3 6489104.420 2728922.580 36 46 22.13465 S 175 26 52.69036 E 

Control4 1 6483629.774 2725572.159 36 49 22.66154 S 175 24 43.67240 E 

Control4 2 6483701.307 2725566.447 36 49 20.34692 S 175 24 43.36306 E 

Control4 3 6483728.157 2725621.611 36 49 19.42725 S 175 24 45.55850 E 

Control5 1 6483397.465 2726755.858 36 49 29.14183 S 175 25 31.67633 E 

Control5 2 6483401.908 2726871.941 36 49 28.89417 S 175 25 36.35390 E 

Control5 3 6483313.936 2726889.342 36 49 31.73141 S 175 25 37.15344 E 

Control6 1 6476754.803 2725443.082 36 53 05.72090 S 175 24 46.05521 E 

Control6 2 6476935.487 2725500.785 36 52 59.81037 S 175 24 48.18501 E 

Control6 3 6476891.177 2725602.119 36 53 01.15729 S 175 24 52.32470 E 

Farm1 1 6497502.816 2724882.784 36 41 53.39044 S 175 24 00.62818 E 

Farm1 2 6497534.657 2724979.005 36 41 52.27289 S 175 24 04.46815 E 

Farm1 3 6497807.139 2724764.999 36 41 43.62574 S 175 23 55.55143 E 

Farm2 1 6491115.973 2727102.095 36 45 18.53497 S 175 25 37.07614 E 

Farm2 2 6491198.826 2726885.246 36 45 16.04164 S 175 25 28.24527 E 

Farm2 3 6491163.297 2726808.068 36 45 17.26259 S 175 25 25.17433 E 

Farm3 1 6493122.034 2728365.674 36 44 12.35156 S 175 26 25.76289 E 

Farm3 2 6493047.242 2728342.863 36 44 14.79737 S 175 26 24.92718 E 

Farm3 3 6492933.649 2728420.224 36 44 18.41156 S 175 26 28.17072 E 

Farm4 1 6491078.472 2729409.640 36 45 17.68150 S 175 27 10.11241 E 

Farm4 2 6490986.577 2729437.441 36 45 20.63642 S 175 27 11.33569 E 

Farm4 3 6490911.420 2729493.276 36 45 23.02327 S 175 27 13.67006 E 

Farm5 1 6486781.511 2728133.933 36 47 38.17054 S 175 26 23.48940 E 

Farm5 2 6486798.342 2728116.158 36 47 37.64069 S 175 26 22.75395 E 

Farm5 3 6486734.570 2727954.714 36 47 39.85343 S 175 26 16.31545 E 

Farm6 1 6484696.010 2727344.835 36 48 46.50623 S 175 25 53.99018 E 

Farm6 2 6484688.866 2727396.408 36 48 46.69179 S 175 25 56.07814 E 

Farm6 3 6484749.781 2727421.158 36 48 44.69427 S 175 25 57.00860 E 

Farm7 1 6481444.900 2725902.800 36 50 33.21997 S 175 24 59.42461 E 

Farm7 2 6481311.700 2725842.809 36 50 37.59275 S 175 24 57.15140 E 

Farm7 3 6481386.710 2725855.863 36 50 35.14869 S 175 24 57.59517 E 

Farm8 1 6478720.508 2725190.737 36 52 02.19992 S 175 24 33.69919 E 

Farm8 2 6478821.451 2725389.103 36 51 58.75055 S 175 24 41.59386 E 

Farm8 3 6478624.956 2725225.101 36 52 05.26807 S 175 24 35.19154 E 

32


Appendix 2. Physico-chemical and biological data, and biotic indices, from grab samples at the eight reference farm sites and the six control sites. 

Stations TOC TN 

Gravel 

(>2mm) 

Sand 

(63µm) 

Silt & 

Clay 

(


Appendix 2. continued 

Stations TOC TN 

Gravel 

(>2mm) 

Sand 

(63µm) 

Silt & 

Clay 

(


Appendix 3. Sediment core photographs from the eight reference farm sites and the six 

control sites. 

Farm1 

Farm2 

Farm3 

Control1 

Control 2 

Control 3 

35



Farm 4 

Farm 5 

36 

Control 4 

Control 5 

Farm 6 Control 6



Farm 7 

Farm 8 

37


Appendix 4. Complete list of biota recorded from grab samples at reference farm sites 

and control sites. 

Taxa Gen/Group Common Name 

38 

Infauna 

/Epifauna 

Total 

# 

Average 

# 

Relative 

# 

Sponge (bread) Porifera Sponge Unid. e 1 1.0 0.0 

Sycon sp. Porifera Glass sponge e 1 1.0 0.0 

Anthopleura aureoradiata Anthozoa Anemone e 36 9.0 1.0 

Edwardsia sp. Anthozoa Burrowing anemone i 3 1.0 0.1 

Platyhelminthes Platyhelminthes Flat Worm e 9 1.5 0.2 

Nemertea Nemertea Proboscis worms i 26 1.3 0.7 

Ischnochiton maorianus Polyplacophora Chiton e 3 3.0 0.1 

Leptochiton inquinatus Polyplacophora Chiton e 19 3.8 0.5 

Gastropoda ( rissoid like) Gastropoda Unidentified gastropod e 2 2.0 0.1 

Amalda australis Gastropoda Southern olive shell e 1 1.0 0.0 

Amalda mucronata Gastropoda Olive Shell e 6 2.0 0.2 

Austrofusus glans Gastropoda Whelk e 1 1.0 0.0 

Caecum digitulum Gastropoda Snail e 1 1.0 0.0 

Cominella maculosa Gastropoda Spotted Whelk e 1 1.0 0.0 

Cominella virgata Gastropoda Whelk e 1 1.0 0.0 

Crepidula monoxyla Gastropoda Slipper shell e 2 2.0 0.1 

Neoguraleus sp. Gastropoda Snail e 1 1.0 0.0 

Sigapatella novaezelandiae Gastropoda Circular slipper limpet e 57 57.0 1.5 

Zegalerus tenuis Gastropoda Snail e 5 1.7 0.1 

Opisthobranchia Unid. Opisthobranchia Slug e 2 2.0 0.1 

Philine auriformis Opisthobranchia White Slug e 27 2.1 0.7 

Arthritica bifurca Bivalvia Small bivalve i 2 1.0 0.1 

Borniola sp. Bivalvia Small bivalve i 2 2.0 0.1 

Chlamys sp. Bivalvia Fan Scallop e 1 1.0 0.0 

Corbula zelandica Bivalvia Small bivalve i 3 3.0 0.1 

Crassostrea gigas Bivalvia Pacific Oyster e 2 2.0 0.1 

Dosinia lambata Bivalvia Silky Dosina i 1 1.0 0.0 

Hiatella arctica Bivalvia Saltwater clam i 2 1.0 0.1 

Limaria orientalis Bivalvia File Shell e 8 2.0 0.2 

Melliteryx parva Bivalvia Bivalve i 1 1.0 0.0 

Mytilus galloprovincialis Bivalvia Blue mussel e 1 1.0 0.0 

Nucula gallinacea Bivalvia Nut shell i 4 1.3 0.1 

Nucula nitidula Bivalvia Nut shell i 15 2.1 0.4 

Pecten novaezelandiae Bivalvia Scallop; Tipa e 2 2.0 0.1 

Perna canaliculus Bivalvia Green Lipped Mussel e 18 6.0 0.5 

Tawera spissa Bivalvia Morning Star i 1 1.0 0.0 

Theora lubrica Bivalvia Window Shell i 217 7.2 5.8 

Zenatia acinaces Bivalvia Bivalve i 4 1.0 0.1 

Oligochaeta Oligochaeta 

Polychaeta: 

Oligochaete worms i 74 4.9 2.0 

Ampharetidae 

Ampharaetidae 

Polychaeta: 

Polychaete worm i 7 1.2 0.2 

Chrysopetalum sp. 

Chrysopetalidae 

Polychaeta: 


Leitoscoloplos kerguelensis Orbiniidae 

Polychaeta: 


Orbinia papillosa 

Orbiniidae 

Polychaeta: 


Scoloplos cylindrifer 

Orbiniidae Polychaete worm i 5 1.7 0.1



Infauna 

/Epifauna 

Total 

# 

Average 

# 

Relative 

# 

Paraonidae 

Polychaeta: 

Paraonidae 

Polychaeta: 


Cossura consimilis 

Cossuridae 

Polychaeta: 


Boccardia sp. 

Spionidae 

Polychaeta: 


Paraprionospio pinnata Spionidae 

Polychaeta: 


Prionospio aucklandica Spionidae 

Polychaeta: 


Prionospio multicristata Spionidae 

Polychaeta: 


Prionospio yuriel 

Spionidae 

Polychaeta: 


Spiophanes kroyeri 

Spionidae 

Polychaeta: 


Chaetopterus sp. 

Chaetopteridae 

Polychaeta: 


Phyllochaetopterus socialis Chaetopteridae 

Polychaeta: 

Parchment worm i 2 1.0 0.1 

Capitella capitata 

Capitellidae 

Polychaeta: 


Capitellethus zeylanicus Capitellidae 

Polychaeta: 


Heteromastus filiformis Capitellidae 

Polychaeta: 


Maldanidae 

Maldanidae 

Polychaeta: 

Bamboo Worms i 16 4.0 0.4 

Armandia maculata 

Opheliidae 

Polychaeta: 


Phyllodocidae 

Phyllodocidae 

Polychaeta: 

Paddle worms i 20 2.2 0.5 

Polynoidae 

Polynoidae 

Polychaeta: 

Scale worms i 42 1.8 1.1 

Sigalionidae 

Sigalionidae 

Polychaeta: 


Hesionidae 

Hesionidae Polychaete worm i 21 1.6 0.6 

Syllidae Polychaeta: Syllidae Polychaete worm i 18 2.0 0.5 

Sphaerosyllis sp. Polychaeta: Syllidae Polychaete worm i 166 8.7 4.4 

Nereidae (juvenile) Polychaeta: Nereidae 

Polychaeta: 

Rag worms i 5 1.7 0.1 

Glyceridae 

Glyceridae 

Polychaeta: 


Goniada sp. 

Goniadidae 

Polychaeta: 


Aglaophamus sp. 

Nephtyidae 

Polychaeta: 


Onuphis aucklandensis Onuphidae 

Polychaeta: 


Eunicidae 

Eunicidae 

Polychaeta: 


Lumbrineridae 

Lumbrineridae 

Polychaeta: 


Dorvilleidae 

Dorvilleidae 

Polychaeta: 


Cirratulidae 

Cirratulidae 

Polychaeta: 


Flabelligeridae 


Polychaeta: 


Flabelligera affinis 


Polychaeta: 


Pectinaria australis 

Pectinariidae 

Polychaeta: 


Terebellidae 

Terebellidae 

Polychaeta: 


Euchone pallida 

Sabellidae Fan worm i 4 1.0 0.1 

Pomatoceros sp. Polychaeta: Fan worm e 3 3.0 0.1 

39



40 

Infauna 

/Epifauna 

Total 

# 

Average 

# 

Relative 

# 

Serpula sp. 

Serpulidae 

Polychaeta: 

Serpulidae Fan worm e 7 3.5 0.2 

Nebalia sp. Crustacea Crustacean e 5 1.7 0.1 

Notostraca Crustacea Tadpole shrimps e 1 1.0 0.0 

Mysidacea Mysidacea Mysid shrimp e 12 1.3 0.3 

Cumacea Cumacea Cumaceans e 135 5.6 3.6 

Tanaid sp. Tanaidacea Tanaid Shrimp i 6 2.0 0.2 

Anthuridea Isopoda Isopod e 14 4.7 0.4 

Munna schauinslandi Isopoda Isopod e 8 2.0 0.2 

Aoridae Amphipoda Amphipod (Family) e 37 4.1 1.0 

Caprellidae Amphipoda Amphipod (Family) e 1 1.0 0.0 

Corophiidae Amphipoda Amphipod (family) e 2 2.0 0.1 

Dexaminidae Amphipoda Amphipod (Family) e 3 1.5 0.1 

Liljeborgiidae Amphipoda Amphipod (family) e 12 6.0 0.3 

Lysianassidae Amphipoda Amphipods e 20 3.3 0.5 

Melitidae Amphipoda Amphipod e 109 5.5 2.9 

Phoxocephalidae Amphipoda Amphipod (family) e 483 21.0 12.9 

Amphipoda indet. Amphipoda Amphipod (Family) e 2 2.0 0.1 

Alpheus sp. Decapoda Snapping shrimp e 5 1.3 0.1 

Betaeus sp. Decapoda Shrimp e 3 1.0 0.1 

Halicarcinus cookii Decapoda Pill-box Crab e 26 2.2 0.7 

Halicarcinus whitei Decapoda Pill-box Crab e 1 1.0 0.0 

Macrophthalmus hirtipes Decapoda Stalk-eyed Mud Crab i 19 1.6 0.5 

Neolithodes brodiei Decapoda Crab i 1 1.0 0.0 

Notomithrax minor Decapoda Masking crab i 5 1.7 0.1 

Pagurus sp. Decapoda Hermit Crab e 11 2.2 0.3 

Palaemon affinis Decapoda Estuarine Prawn e 10 1.7 0.3 

Petrolisthes elongatus Decapoda Half crab e 38 2.7 1.0 

Pinnotheres novaezelandiae Decapoda Mussel Pea Crab e 28 14.0 0.7 

Pyromaia tuberculata Decapoda Spider crab e 3 1.5 0.1 

Upogebia danai Decapoda Mud Shrimp i 13 2.6 0.3 

Decapoda (larvae unid.) Decapoda Crab Larvae e 199 66.3 5.3 

Cymbicopia hispida Ostracoda Ostracod e 1 1.0 0.0 

Cypridinodes concentrica Ostracoda Ostracod e 18 2.0 0.5 

Diasterope grisea Ostracoda Ostracod e 3 1.0 0.1 

Neonesidea sp. Ostracoda Ostracod i 65 4.3 1.7 

Parasterope quadrata Ostracoda Ostracod e 9 1.3 0.2 

Scleroconcha arcuata Ostracoda Ostracod e 13 4.3 0.3 

Trachyleberis lytteltonsis Ostracoda Ostracod i 13 1.9 0.3 

Copepoda Copepoda Copepods e 3 1.0 0.1 

Balanus sp. Cirripedia Barnacle e 27 5.4 0.7 

Bryozoa (encrusting) Bryozoa Bryozoan e 6 1.5 0.2 

Bryozoa (solid stalked) Bryozoa Bryozoan e 4 1.3 0.1 

Waltonia inconspicua Brachiopoda Lamp shell e 2 2.0 0.1 

Echinocardium cordatum Echinoidea Heart Urchin i 8 1.6 0.2 

Patiriella regularis Asteroidea Cushion Star e 2 1.0 0.1 

Ophiuroidea Ophiuroidea Brittle stars i 95 5.0 2.5 

Trochodota dendyi Holothuroidea Sea cucumber i 1 1.0 0.0 

Asterocarpa sp. Ascidiacea Sea squirt e 1 1.0 0.0



Infauna 

/Epifauna 

Total 

# 

Average 

# 

Cnemidocarpa bicornuta Ascidiacea Saddle squirt e 3 1.0 0.1 

Didemnum sp. Ascidiacea Colonial sea squirt e 2 2.0 0.1 

Relative 

# 

Styela clava Ascidiacea Sea squirt e 1 1.0 0.0 

41


Appendix 5. Results of the Simper analysis for infauna abundance data from grab 

samples at reference farm sites and control sites at 35% similarity (Primer 6). 

SIMPER 

Similarity Percentages - species contributions 

One-Way Analysis 

Data worksheet 

Name: Data2 

Data type: Abundance 

Sample selection: All 

Variable selection: All 

Parameters 

Resemblance: S17 Bray Curtis similarity 

Cut off for low contributions: 90.00% 

Factor Groups 

Sample 35 Percent 

Control 1 Nth: CONTROL1NTH-G1 c 

Control 1 Nth: CONTROL1NTH-G2 c 

Control 2 Nth: Control2NTH-G2 c 

Control 3 Nth: Control3Nth-G1 c 



Control 4 Sth: Control4Sth-G1 c 







Li292: Li292FARM2-G3 c 

Li362: LI362FARM6-G1 c 



Control 1 Nth: CONTROL1NTH-G3 b 

Control 4 Sth: Control4Sth-G3 b 

Control 6 Sth: Control6Sth-G2 b 

Li292: Li292FARM2-G1 b 











Li362: LI362FARM6-G2 b 

Li362: LI362FARM6-G3 b 








Control 2 Nth: Control2NTH-G1 a 

Control 2 Nth: Control2NTH-G3 a 

Group c 

Average similarity: 42.07 

Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% 

Sigalionidae 1.11 8.64 2.14 20.53 20.53 

Cossura consimilis 0.86 5.52 1.07 13.12 33.65 

Aglaophamus sp. 0.86 4.53 0.93 10.78 44.43 

42



Heteromastus filiformis 0.75 3.82 0.77 9.08 53.51 

Neonesidea sp. 0.82 3.20 0.67 7.59 61.10 

Theora lubrica 0.74 2.92 0.68 6.94 68.05 

Cirratulidae 0.67 2.70 0.69 6.43 74.47 

Lumbrineridae 0.58 2.22 0.59 5.28 79.75 

Prionospio yuriel 0.58 2.06 0.59 4.89 84.64 

Ophiuroidea 0.50 1.33 0.42 3.17 87.81 

Macrophthalmus hirtipes 0.46 1.32 0.42 3.13 90.94 

Group b 


Species Av.Abund Av.Sim Sim/SD Contrib% Cum.% 

Prionospio yuriel 1.35 4.75 1.41 10.80 10.80 

Theora lubrica 1.36 4.59 1.36 10.44 21.24 

Heteromastus filiformis 1.39 4.46 1.27 10.14 31.37 

Polynoidae 0.89 2.99 1.14 6.80 38.17 

Sigalionidae 0.94 2.97 1.00 6.74 44.91 

Prionospio multicristata 1.17 2.71 0.89 6.15 51.07 

Oligochaeta 0.83 2.48 0.70 5.64 56.71 

Terebellidae 0.85 2.31 0.91 5.26 61.97 

Sphaerosyllis sp. 1.01 2.07 0.80 4.71 66.68 

Armandia maculata 0.91 1.86 0.72 4.23 70.91 

Nemertea 0.69 1.77 0.80 4.03 74.95 

Cirratulidae 0.77 1.77 0.70 4.03 78.97 

Paraonidae 0.70 1.42 0.56 3.24 82.21 

Glyceridae 0.66 1.12 0.58 2.55 84.76 

Ophiuroidea 0.66 0.82 0.45 1.85 86.61 

Hesionidae 0.49 0.70 0.45 1.58 88.20 

Lumbrineridae 0.44 0.59 0.39 1.34 89.54 

Pectinaria australis 0.42 0.56 0.34 1.28 90.83 

Group a 


Species Av.Abund Av.Sim Contrib% Cum.% 

Lumbrineridae 1.19 10.23 19.21 19.21 

Nucula gallinacea 1.09 8.60 16.16 35.37 

Phyllodocidae 1.00 8.60 16.16 51.53 

Polynoidae 1.00 8.60 16.16 67.69 

Aglaophamus sp. 1.00 8.60 16.16 83.84 

Ophiuroidea 1.00 8.60 16.16 100.00 

Groups c & b 

Average dissimilarity = 68.36 

Species Group c Group b Av.Diss Diss/SD Contrib% Cum.% 

Av.Abund Av.Abund 

Prionospio multicristata 0.06 1.17 3.30 1.30 4.82 4.82 

Prionospio yuriel 0.58 1.35 3.10 1.18 4.53 9.35 

Theora lubrica 0.74 1.36 2.93 1.28 4.28 13.64 

Oligochaeta 0.06 0.83 2.91 1.06 4.26 17.90 

Heteromastus filiformis 0.75 1.39 2.77 1.29 4.06 21.96 

Sphaerosyllis sp. 0.25 1.01 2.62 1.24 3.84 25.80 

Neonesidea sp. 0.82 0.17 2.50 1.01 3.66 29.46 

Armandia maculata 0.12 0.91 2.47 1.19 3.61 33.07 

Polynoidae 0.25 0.89 2.42 1.31 3.54 36.61 

Aglaophamus sp. 0.86 0.43 2.35 1.17 3.44 40.05 

Cossura consimilis 0.86 0.38 2.32 1.16 3.40 43.45 

Terebellidae 0.24 0.85 2.29 1.26 3.35 46.80 

Paraonidae 0.24 0.70 2.17 1.00 3.17 49.97 

Ophiuroidea 0.50 0.66 2.13 1.05 3.12 53.09 

Cirratulidae 0.67 0.77 2.13 1.10 3.12 56.21 

Lumbrineridae 0.58 0.44 1.89 1.01 2.76 58.98 

Nemertea 0.25 0.69 1.88 1.13 2.75 61.73 

Glyceridae 0.19 0.66 1.85 1.03 2.71 64.44 

Sigalionidae 1.11 0.94 1.63 0.94 2.39 66.83 

Macrophthalmus hirtipes 0.46 0.24 1.61 0.87 2.36 69.18 

Hesionidae 0.18 0.49 1.47 0.87 2.15 71.33 

43



Species Group c Group b Av.Diss Diss/SD Contrib% Cum.% 

Av.Abund Av.Abund 

Dorvilleidae 0.12 0.46 1.36 0.77 1.98 73.31 

Pectinaria australis 0.00 0.42 1.30 0.70 1.91 75.22 

Syllidae 0.06 0.41 1.24 0.72 1.81 77.03 

Trachyleberis lytteltonsis 0.35 0.09 1.11 0.65 1.62 78.66 

Onuphis aucklandensis 0.24 0.13 1.03 0.62 1.51 80.16 

Nucula nitidula 0.23 0.13 0.89 0.56 1.30 81.47 

Phyllodocidae 0.00 0.37 0.89 0.65 1.30 82.77 

Echinocardium cordatum 0.26 0.04 0.86 0.57 1.25 84.02 

Capitella capitata 0.00 0.27 0.84 0.55 1.22 85.24 

Flabelligeridae 0.19 0.15 0.82 0.57 1.19 86.44 

Boccardia sp. 0.00 0.33 0.77 0.57 1.13 87.57 

Ampharetidae 0.07 0.22 0.72 0.54 1.05 88.61 

Upogebia danai 0.00 0.27 0.68 0.51 0.99 89.61 

Capitellethus zeylanicus 0.06 0.22 0.67 0.56 0.98 90.59 

Groups c & a 


Group c Group a 

Species Av.Abund Av.Abund Av.Diss Diss/SD Contrib% Cum.% 

Sigalionidae 1.11 0.00 4.93 2.78 6.87 6.87 

Nucula gallinacea 0.06 1.09 4.58 3.08 6.38 13.25 



Neonesidea sp. 0.82 0.75 3.56 1.14 4.96 29.74 

Polynoidae 0.25 1.00 3.45 1.74 4.82 34.56 

Ophiuroidea 0.50 1.00 3.08 1.51 4.29 38.85 



Cirratulidae 0.67 0.00 2.75 1.14 3.84 50.59 




Arthritica bifurca 0.00 0.50 2.33 0.96 3.25 64.40 

Dosinia lambata 0.00 0.50 2.33 0.96 3.25 67.64 

Nemertea 0.25 0.50 2.18 0.98 3.04 70.69 

Terebellidae 0.24 0.50 2.13 0.97 2.96 73.65 


Edwardsia sp. 0.06 0.50 2.09 0.97 2.91 79.48 



Trachyleberis lytteltonsis 0.35 0.00 1.36 0.62 1.90 86.82 

Onuphis aucklandensis 0.24 0.00 1.07 0.54 1.49 88.30 

Echinocardium cordatum 0.26 0.00 1.03 0.54 1.44 89.74 

Paraonidae 0.24 0.00 1.00 0.53 1.40 91.14 

Groups b & a 


Species Group b 

Group a Av.Diss Diss/SD Contrib% Cum.% 

Av.Abund 

Av.Abund 


Nucula gallinacea 0.00 1.09 3.52 3.33 4.62 10.28 

Prionospio multicristata 1.17 0.00 3.32 1.32 4.36 14.64 



Oligochaeta 0.83 0.00 2.94 1.08 3.86 26.69 

Sigalionidae 0.94 0.00 2.94 1.51 3.85 30.54 

Sphaerosyllis sp. 1.01 0.00 2.70 1.25 3.55 34.09 



Ophiuroidea 0.66 1.00 2.60 1.83 3.42 44.47 

Armandia maculata 0.91 0.00 2.48 1.17 3.25 47.72 


Neonesidea sp. 0.17 0.75 2.30 0.97 3.03 53.87 

44



Species Group b 

Group a Av.Diss Diss/SD Contrib% Cum.% 

Av.Abund 

Av.Abund 

Cirratulidae 0.77 0.00 2.26 1.13 2.97 56.84 

Paraonidae 0.70 0.00 2.18 0.96 2.86 59.70 

Terebellidae 0.85 0.50 2.04 1.15 2.68 62.38 


Glyceridae 0.66 0.00 1.77 1.00 2.33 67.12 

Nemertea 0.69 0.50 1.69 0.99 2.22 69.34 

Dosinia lambata 0.00 0.50 1.67 0.92 2.19 71.54 

Arthritica bifurca 0.04 0.50 1.66 0.92 2.18 73.72 


Edwardsia sp. 0.04 0.50 1.54 0.93 2.02 77.77 

Hesionidae 0.49 0.00 1.31 0.81 1.72 79.49 

Pectinaria australis 0.42 0.00 1.29 0.70 1.69 81.18 

Dorvilleidae 0.46 0.00 1.19 0.70 1.57 82.75 

Syllidae 0.41 0.00 1.14 0.69 1.50 84.25 


Polynoidae 0.89 1.00 1.10 0.75 1.45 87.16 

Capitella capitata 0.27 0.00 0.83 0.55 1.09 88.25 

Boccardia sp. 0.33 0.00 0.77 0.57 1.01 89.26 


45


Appendix 6. Benthic maps for the eight reference farm sites, showing estimated extent of 

mussel shell drop-off and sediment grain-size results. 

46 

Farm 1 

25m 

30m 35m 

245m from 

shore 

Li373 

5m 10m 15m 20m 

Moturua Island 

0 37.575 

150 225 300 

m 

Farm 2 

Motukopake Island 

15m 

Li293 

65 m from 

shore 

20m 25m 

Li292A 

Stocking 

density 

= 11 lines 

Li292B 

Stocking 

density 

= 10 lines 

5m 10m 15m 20m 

0 30 60 120 180 240 

m 

Li396 

Stocking 

density 

= 14 lines 

Li333 

Li294 

Li294 

± 

Li361 Li361 

Moturuhi 

Is. 

Moturua 

Is. 

30m 

30m 

Li396 current farm area 

Li373 & 361 current farm areas 

Li396 currently consented area 

Li373 farm extension 

± 

Waimate 

Is. 


Li293, 294 & 333 current farm area 



Coromandel 

± 

± 

T5 

Inshore west 

4 

Li373 

0 2550 

100 150 200 

m 

293 

inner T4 

Motukopake Island 

Inner outer T1 

Li293 

292 

inner T4 

Li292A 

3 

1 

Li292B 

0 30 60 120 180 240 

m 

South 361 north 396 

3 

Li396 

2 

4 

T5 

T6 

Li333 

1 

Li294 

Li294 

Li361 

Li396 

361 north 

2 

Sediment Key 

Li361 

South 361-396 

Gravel 

Sand 

Sand & clay 




Mussel extent 

Video transect 

North T1 


Sediment Key 

Gravel 

Sand 

Silt & clay 

Li293, 294 & 333 current farm area 


Mussel extent 


T6


Farm 3 

± 

Waimate 

Is. 

17 m 

Coromandel 

Li346 

Stocking density 

= 12 lines 

720 m from 

shore 

13 m 

Li310 W 

0 65 130 260 390 520 

m 

Sediment Key 

346 west 

T1 

Gravel 

Sand 

Silt & clay 

2 

346 northeast 

1 

4 

Li346 

3 

Li310 W 

310 south T2 

7 m 

Li310 E 

0 50 100 200 300 400 

m 

5 m 

310 east 

heading north 

Li310 E 

310 east T3 

Oahuru Bay 

Li326 


Li310 & 326 current farm area 

Li346 currenlty consented area 


Li326 

326 southwest 




Li346, 310 & 326 mussel extent 


± 

326 east 

47


48 

Farm 4 

± 

Waimate 

Is. 

Sediment Key 

Gravel 

Sand 

343 west 

Silt and clay 

Coromandel 

343 north 

Li343 

Li343 

0 50 100 150 200 

25 

m 

296 north 

343 inshore 

90 m from 

shore 

Motukakarikitahi 

Island 

4 

Motukakarikitahi 

Island 

Li296 


= 18 lines 

1 

2 

296-343 

south 

Li296 

3 

10 m 

Li383 

0 2550 

100 150 200 

m 




Li 343 & 383 current farm area 

Li383 

383-296 

south 




Li343, 296 & 383 mussel extent 


383 north 

± 

383 east


Farm 5 

Whanganui 

Island 

5 m 

100 m from 

shore 

10 m 


= 17 lines 

0 20 40 80 120 160 

m 

± 

T4 

T3 

3 

Li380 + Li421 

T1 

Li380 

Li421 

Li380 

0 25 50 100 150 200 

m 

2 

4 

1 

T2 

± 

Coromandel 

Te Kouma 

Li 380 + Li421 current farm area 




Li380 + Li421 current farm area 


Mussel extent 


Sediment Key 

Gravel 

Sand 

Silt and clay 

49


50 

Farm 6 

10 m 

5 m 

± 

T3 

4 

Li362 


= 15 lines 

140 m from shore 

1 

T2 

Li362 

0 20 40 80 120 160 

m 

2 

3 

T1 

T4 

± 

5 m 

Te Kouma 


Coromandel 

0 1530 

60 90 120 

m 



Sediment Key 



Mussel extent 


Gravel 

Sand 

Silt and clay


Farm 7 

15 m 

10 m 

5 m 

Li379 


= 11 lines 

0 15 30 

± 

60 90 120 

m 

T4 

2 

3 

0 15 30 60 90 120 

m 

1 

T1 

T3 

Li379 

Wekarua Island 

110 m from shore 

4 

T2 

± 

Li378 





Coromandel 

Te Kouma 

Sediment Key 

Manaia 

Li378 




Mussel extent 


Gravel 

Sand 

Silt and clay 

51


52 

Farm 8 

10 m 5 m 

0 25 50 100 150 200 

m 

± 

T1 

4 

Li344B 

Stocking density = 14 lines 

0 30 60 120 180 240 

m 

1 

Li344A 


= 4 lines 

3 

15 m 

Li344A 

Li344B 

2 

T3 

± 

85 m to shore 

10 m 




T2 

Te Kouma 

Sediment Key 

Manaia 

Kirita Bay 



Mussel extent 


Gravel 

Sand 

Silt and clay


Control 1 

3 

1 

Control 1 

0 25 50 100 150 200 

m 

Control 2 

Motuwi Island 

1 

0 25 50 100 150 200 

m 

3 

2 

2 

Control 2 

Motuwi 

Is. 

Moturua 

Is. 

Motuoruhi Is. 

Sediment Key 

± Motuoruhi 

Is. 

Ngohitanu 

Bay 

Gravel 

Sand 

± 

Silt and clay 

Waimate 

Is. 

Sediment Key 

Gravel 

Sand 

Silt and clay 

53


54 

Control 3 

1 

2 

Control 3 

0 30 60 120 180 240 

m 

Control 4 

Sediment Key 

Gravel 

Sand 

Silt and clay 

3 

Control 4 

2 

1 

Rangipukea 

Island 

3 

± 

Whanganui 

Island 

± 

Sediment Key 

Coromandel 

Gravel 

Sand 

Silt and clay 

Coromandel 

Te Kouma 

Manaia 

0 25 50 100 150 200 

m


Control 5 

0 25 50 100 150 200 

m 

Control 6 

Control 6 

1 

0 15 30 60 90 120 

m 

1 

Control 5 

2 

2 

3 

3 

± 

± 

Te Kouma 

Manaia 

Sediment Key 

Coromandel 

Gravel 

Sand 

Silt and clay 

Te Kouma 

Sediment Key 

Manaia 

> 600 m to shore 

Gravel 

Sand 

Silt and clay 

55


Appendix 7. Cawthron short reports for 32 proposed inshore mussel farm extensions. 

56

To: Waikato Regional Council 

Private Bag 3038 

Waikato Mail Centre 

HAMILTON 3240 

1. Applicant: Moturoa Trust No 2 

LI 373/ CN 112682 

Application for Resource Consent 

under s88 of the Resource Management Act 

2. Resource Consents Sought: 

Resource consent is sought to use and occupy space in the coastal marine area for 

conventional mussel farming, spat catching and the farming of oysters and scallops, and 

associated structures, and to undertake associated discharges to water and disturbance of 

and deposition on the seabed. 

The area that the application relates to is a one hectare extension to an existing marine farm 

in the Coromandel area. The location is identified and activities discussed in more detail in 

the attached Assessment of Environmental Effects (AEE). 

No other resource consents are required for the proposed activity. 

The term of the consent sought is for approximately 13 years (ie to be consistent with the 

term of the neighbouring consented farm). 

3. Assessment of Environmental Effects 

Attached to this application, is an AEE that corresponds with the scale and significance of the 

effects of the proposed activity and which is set out in accordance with Schedule 4 of the 

RMA. In addition the report: Taylor, D., Clark, D., Keeley, N., Goodwin, E., 2012. Assessment 

of Benthic and Water Column Effects from Inshore Coromandel Mussel Farms; Prepared for a 

Collective of Coromandel Mussel Farmers. Cawthron Institute, is relied on in support of this 

application. 

4. Address for Service 

This application along with a $500 deposit has been filed by Robin Britton, consultant to the 

applicant. The addresses for service are jointly as follows: 

Robin Britton 

PO Box 7016 

Hamilton East 3247 

Moturoa Trust No 2 

PO Box 716 

Thames 3540 

Any queries can be made to Robin Britton at: 027 281 2969; or rbritton@wave.co.nz 

Date: 

Signature: R Britton on behalf of the applicant

ASSESSMENT OF EFFECTS ON THE ENVIRONMENT 

Coromandel Marine Farm Extension 

MOTURUA TRUST NO 2 

FARM: LI 373/ CN 112682 

June 2012 

Prepared by: 

Robin Britton 

Resource Management Consultant 

PO Box 7016 

Hamilton 3247

Contents 

2 

Contents ..................................................................................................................................................... 2 

1. Introduction ..................................................................................................................................... 3 

2. Description of the Proposal ........................................................................................................ 3 

3. Consideration of possible alternative locations .................................................................. 5 

4. Assessment of actual or potential effects............................................................................. 5 

4. Description of mitigation measures ...................................................................................... 12 

5. Consultation ................................................................................................................................... 13 

6. Monitoring ....................................................................................................................................... 13 

7. Relevant Planning Provisions................................................................................................... 14 

8. Consent Conditions ..................................................................................................................... 18 

9. Notification ..................................................................................................................................... 18 

10 Conclusions .................................................................................................................................... 19 

Appendix 1: Survey plan showing location of the farm and proposed extension ........ 20 

Appendix 2: Short Report - Coromandel Mussel Farm Extension – LI 373 .................... 21 

2

3 

ASSESSMENT OF EFFECTS ON THE ENVIRONMENT 

MARINE FARM EXTENSION 

Prepared in accordance with Section 88(2)(b) of the Resource Management Act and taking into 

account the provisions of the Waikato Regional Coastal Plan (RCP). 

1. Introduction 

1.1 This assessment of effects on the environment (AEE) relates to a one hectare extension to 

the following farm owned by Moturua Trust No 2: 

LI 373/ CN 112682 

1.2 Rule 16.5.5A (Extensions of Marine Farms) of the RCP enables an extension of an existing 

farm to be applied for. This application is for new space. 

1.3 The current consented area of the farm is 6 hectares. The farm is the northernmost farm 

of those that are generally located off-shore from Moturua Island, as shown on the RCP 

Map 14. 

1.4 The survey plan showing the location and position of the area which is being applied for, 

is attached in Appendix 1. 

1.5 The farming of mussels (Perna canaliculus) and spat catching, and the farming of oysters 

and scallops will be the activities undertaken within the area being applied for. 

1.6 In accordance with Rule 16.5.5A of the RCP, this consent application is for a discretionary 

activity. 

1.7 The existing consented marine farm provides the base-line from which the effects of the 

area being applied for are to be considered. 

1.8 This AEE is structured using the headings of the Fourth Schedule to the RMA, and also 

addresses the information requirements of the RCP contained in Appendices I and 1A, and 

the matters raised in Rule 16.5.5A. 

2. Description of the Proposal 

2.1 This application seeks a one hectare extension to an existing consented area to erect, 

place and use structures and occupy space, along with associated discharges to water and 

air, and disturbances of and deposition to the seabed in the coastal marine area (CMA). 

The extension would be used for conventional longline structures for the purpose of 

farming mussels (Perna canaliculus), oysters and scallops, including spat catching. The 

term of the consent being sought is for 13 years – to enable the term of the area which is 

the subject of this application, to be made concurrent with the term of the existing 

3

4 

marine farm (which expires on 1 January 2025). The application relates to the one 

hectare area identified on the Survey Plan in Appendix 1. 

2.2 No other resource consents are required for this activity. 

2.3 There is a functional need for this activity to be located within the coastal marine area. 

2.4 The layout to be used includes 4 double backbones per hectare, which would be aligned 

with the direction of the existing lines of the current consented area and orientated 

parallel to tidal flows. 

2.5 The buoys to be used to support the longlines will be between 200 – 300 litres in volume. 

2.6 The anchors to be used are screw anchors buried to approximately 6m. 

2.7 The longline structures to be used include: 

backbone/mainline length 130 - 160m 

dropper length 10m 

backbone and mooring line rope type – 24 - 36mm polypropylene; 

surface buoy separation – 2m to 10m (depending on stocking rate and size); 

buoys will be orange at the corners of blocks and at the middle of the most seaward 

and most landward lines; all other buoys will be black; 

the proposed lighting is to mark corners B & F as shown on the plan in Appendix 1 and 

described further below. Applications for these lights have been submitted to 

Maritime New Zealand for approval. 

oysters and scallops would be hung in cages or trays suspended from the back-bone 

lines 

spat catching would occur on spat role droppers. 

2.8 No additional vessel movements would result from farming the proposed extended area 

of the farm. 

2.9 The applicant currently uses and would continue to use the landing facilities at the Sugar 

Loaf. The use of the Sugar Loaf wharf is an authorised activity. The current resource 

consent for the wharf does not limit the use of the wharf by way of restrictions on vessel 

movements or tonnage crossing the facility. Additional use of the wharf associated with 

this farm extension is therefore a consented activity. 

2.10 It is considered that the quantity of product arising from the additional 1 hectare 

extension would have a minimal impact on the current wharf operations. It is also 

considered that the wharf infrastructure can address the cumulative impacts of other 

proposed extensions in the area, anticipated by Waikato Regional Council to be a 

maximum of 48 hectares (if all existing farms sought an extension). Reference is made to 

the “Wharfing Infrastructure Discussion Document” prepared for the Haruaki 

Development Group, 2010 & 2011, in support of this matter. 

4

5 

2.11 The applicant currently has a private share base in the facilities which would amply cope 

with the extra product from this 1 ha extension. The applicant is also aware of the current 

discussions on future wharf infrastructure options and of Waikato Regional Council’s 

intention to develop an aquaculture strategy which would, among other matters, consider 

the future infrastructural needs of the industry. The applicant would be involved in these 

studies through the Coromandel Marine Farmers Association. 

3. Consideration of possible alternative locations 

3.1 The RMA requires a description of any possible alternative locations or methods for 

undertaking the activity for which consent is sought, where it is likely that the activity will 

result in any significant adverse effect on the environment. The applicant contends that 

there would be no significant adverse effect on the environment arising from this 

application. Alternative sides of the existing consented area were considered for the one 

hectare extension, and in consideration of practicalities such as tidal flows, navigation and 

existing operations, were dismissed. 

3.2 RCP rule 16.5.5A clearly anticipates the application site as being a potentially appropriate 

area for marine farming. 

4. Assessment of actual or potential effects 

4.1 This part of the AEE deals in detail with the actual or potential effects on the environment 

of the proposed activity. It also addresses the matters, where relevant, outlined in the 

Fourth Schedule to the RMA and addresses all relevant matters outlined in Rule 16.5.5A 

and Appendices I and IA of the RCP. The comments made below are supported by the 

scientific report attached as Appendix 2 and the report: Taylor D, Clark D, Keeley N and 

Goodwin E, 2012. Assessment of Benthic and Water Column Effects from Inshore 

Coromandel Mussel Farms. Prepared for a Collective of Coromandel Mussel Farmers. 

Cawthron Institute. 

4.2 Any effect on those in the neighbourhood and, where relevant, the wider community 

including any socio-economic and cultural effects 

4.2.1 The existing farm of 6ha hectares has been farmed since prior to the 

commencement of the RMA in 1991. It is considered that the impacts of a one 

hectare extension on the “neighbourhood” would be no more than minor. 

4.2.2 In terms of socio-economic effects the marine farming industry creates and 

supports a range of direct and indirect employment opportunities in the Thames- 

Coromandel region. It is noted that the 1ha extension is located in highly 

productive waters and will make a valuable economic contribution to the 

applicant’s business. The report “Economic Impact of Coromandel Aquaculture: 

Report prepared for the Hauraki-Coromandel Development Group”, (Wyatt, S., 

5

6 

2011) identified that the aquaculture industry contributed $31.4 million to 

Waikato’s regional GDP in 2010/11. In respect of this application, potential socioeconomic 

effects include employment opportunities from managing, transporting 

and processing additional product. 

4.2.3 The applicant would continue to utilise their existing land-based facilities and 

support infrastructure associated with the existing consented farm. The applicant 

considers these facilities to be sufficient and adequate to service the proposed 

one hectare extension. 

4.2.4 In terms of socio-economic impacts on other parties, the extension to the farm 

would contribute to the recreational fishing opportunities for boating fishers near 

the farm. It is currently common practice for recreational fishers to tie up to 

mussel buoys and fish within the farmed areas. Public access to the farm would 

not be restricted. 

4.2.5 In respect of cultural effects it is considered that the extension would have no 

impacts on cultural matters. The applicant is not aware that the site of the 

extension is of any significance to tangata whenua. To the knowledge of the 

applicant, no cultural issues have been raised in relation to farming in this area. 

4.3 Any physical effect on the locality, including any landscape and visual effects 

Landscape and Visual Effects 

4.3.1 The proposed farm extension is located on the northern and western edges of the 

existing farm. The extension is at its closest boundary approximately (but no 

closer than) 50 metres from shore. The visual impact of the additional one 

hectare over and above the impact of the existing farm is considered to be less 

than minor. There are no dwellings overlooking the existing farm. 

4.3.2 The farm is located offshore from Moturua Island. The natural character of the 

area is already altered by the presence of the existing 3 farms. Moturua Island is 

uninhabited and is primarily bush clad. The proposed additional one hectare 

would have minimal additional impact on the natural character of the area due to 

the small size of the extension and the distance off-shore. In addition the visibility 

of the buoys is only a smaller proportion of the overall surface area of the farm 

due to the requirement to accommodate the anchor warps (which are beneath 

the water line). 

4.3.3 The plan requires orange buoys to delineate the farms (corners and middle of the 

most seaward and most landward lines). This not only identifies each farm block 

but it also has a significant safety role, as it serves to warn other users of the 

marine environment of the farm boundaries. Therefore although bright in colour, 

these buoys serve as an extra navigational aid for other marine users. 

6

7 

4.3.4 The buoys would not be visible from the mainland (distance of approximately 

8kms). The buoys would be visible from the Island from different viewing 

perspectives. However the extra lines envisaged by the extension would have 

minimal additional visual impact as the focus point would generally be on the 

farm as a whole and not on the additional lines. The currently established farm 

also blends into the backdrop landscape of the Island when viewed from sea. 

4.3.5 The two navigation lights marking the seaward-most corners of the farm would 

have a range of 1 nautical mile. The existing light at corner A would not be 

required to be moved, while the existing light at corner A would be moved to 

corner F (refer Appendix 1 map). In discussion with the Harbourmaster, lighting of 

corners E & C were not required as there is a lack of safe passage between the 

farm and the shore. Therefore there would be no increase in visual effects over 

and above the existing lighting. 

4.3.6 The marine vessels that are currently utilised in the farming of the consented site, 

being harvesting barges and small service crafts, all provide occasional minor 

visual attraction. No additional barges or craft over and above what is used 

currently to service the existing farm would be used to service the proposed 

additional lines within the one hectare extension. 

Coastal Processes 

4.3.7 In relation to the effects on coastal processes, reference is made to the attached 

scientific report (Appendix 2) and the report: Taylor D, Clark D, Keeley N and 


Coromandel Mussel Farms. Prepared for a Collective of Coromandel Mussel 

Farmers. Cawthron Institute. In addition reference is made to the Cawthron 

Report 1 which reviews literature related to the effects of mussel farming on 

coastal processes. This report notes that the presence of farms can alter and 

reduce current speeds and can attenuate short-period waves. It further notes 

that “these issues are not considered significant at the present scale of 

development in New Zealand” (pv). 

4.3.8 Based on the information reviewed in the above reports, it is considered that the 

overall effects of the one hectare extension on coastal processes will be 

negligible. 

4.4 Any effect on ecosystems, including effects on plants or animals and any physical 

disturbance of habitats in the vicinity 

4.4.1 In relation to the effects on ecosystems, reference is made to the attached 


1 Keeley, N. et al., 2009. Sustainable Aquaculture in New Zealand: Review of the Ecological Effects of Farming Shellfish and Other Nonfish 

Species. Prepared for Ministry of Fisheries. Cawthron Report No 1476 

7

8 



Farmers. Cawthron Institute. 

4.4.2 It is considered that the one hectare extension would have a less than minor 

impact over and above the effects from the existing consented farm. 

4.4.3 It is also considered that the cumulative effects of the proposed farm extension 

on plants, animals and habitat disturbance will be less than minor, given the 

location of the farm, the proposed density of lines and the existing operations. 

4.4.4 With regard to water quality, the mussel farming industry is subject to various 

stringent requirements (including food and health standards which are set by NZ’s 

Health Authorities and are consistent with USA and EU standards). Therefore the 

water and shellfish quality would be regularly checked to ensure they meet these 

health standards. 

4.4.5 With regard to fishing, there would be no known impacts on customary or 

commercial fishing in this in-shore area. While recreational fishing is commonly 

known to be enhanced by the presence of marine farms. 

Carrying Capacity and Phytoplankton 

4.4.6 In relation to the effects on phytoplankton, reference is made to the attached 




Farmers. Cawthron Institute. In addition it is noted that in the past 10 years or 

more of monitoring undertaken by NIWA at Wilsons Bay, there have been no 

significant issues recorded in terms of phytoplankton depletion. 

4.4.7 The overall small size of the existing farm along with the proposed line layouts for 

the extension to the marine farm will ensure that there is sufficient water flow to 

the mussel lines to provide adequate quantities of phytoplankton. There is 

unlikely to be any material effect on phytoplankton much beyond the boundaries 

of the farm and therefore no impact on the nutrient supplies available to any 

nearby farms. 

4.4.8 It is therefore considered that the one hectare extension would have a less than 

minor impact over and above the effects from the existing consented farm. 

Benthic Assessment 

4.4.9 In relation to the effects on benthic communities, reference is made to the 

attached scientific report (Appendix 2) and the report: Taylor D, Clark D, Keeley N 

and Goodwin E, 2012. Assessment of Benthic and Water Column Effects from 

8

9 

Inshore Coromandel Mussel Farms. Prepared for a Collective of Coromandel 

Mussel Farmers. Cawthron Institute. 

4.4.10 It is therefore considered that the one hectare extension would have a less than 

minor impact over and above the effects from the existing consented farm. 

4.4.11 With respect to marine mammals or seabirds, the applicant has advised that there 

have been no known reports of entanglement, during the operation of the 

existing farm. 

4.5 Any effect on natural and physical resources having aesthetic, recreational, scientific, 

historical, spiritual, cultural, or other special value for present or future generations 

4.5.1 The legislative and subsequent RCP provisions anticipated that any effect on 

natural and physical resources having aesthetic, recreational, scientific, historical, 

spiritual, cultural, or other special value for present or future generations, would 

be less than minor in respect of the proposed farm extension. The proposed 

extension to the existing farm has been recognised as an appropriate use in the 

RCP. 

4.5.2 Potential adverse effects on navigation safety and fishing will be minimal due to 

the small size of the extension. The farm extension is not located in any 

navigation channels or mooring areas. There are no other navigation issues 

associated with the existing farm and none anticipated from the proposed 

extension area. It is considered that the lighting and the buoys (black and 

orange), will facilitate safe public access around the proposed structures. 

4.5.3 Public access through the consented farm and proposed extension will not be 

restricted. There is also high recreational value to fishers for catching fish in the 

vicinity of the farm. 

4.5.4 As mentioned above, the extension to the farm would have minimal adverse 

visual or aesthetic impact on land-based observers. 

4.5.5 There are no known adverse effects of the proposal on tangata whenua interests. 

4.5.6 The applicant has no knowledge of any heritage values which could be adversely 

affected by the proposal. Likewise it is not considered that there would be any 

adverse effects on any nearby Department of Conservation land. 

4.5.7 In terms of the use of the Sugar Loaf wharf, any potential adverse effects will be 

minimal due to the fact that no additional service vessels will be required and the 

product from the one hectare will be negligible in respect to the total product 

crossing the wharf. 

9

10 

4.5.8 The capacity of the wharf to accommodate the proposed increase in product from 

the extension to the existing farm (and cumulatively from other extensions in the 

area being applied for), is assessed as being adequate. Existing industry operators 

currently manage the use of the facility in accordance with the operational 

management plan 2 (which addresses issues such as traffic control, loading and 

carpark manoeuvring and locations and storage of equipment). This assessment 

is based on the current tonnage crossing the wharf being estimated at 

approximately 25,000 tonnes 3 and an expectation that the wharf can adequately 

accommodate at least 35,000 tonnes 4 . Notwithstanding the recently approved 

quantities anticipated from Wilsons Bay Area B developments, it is considered 

that there is currently sufficient capacity to accommodate the cumulative product 

from the anticipated farm extensions. It is anticipated that any effects resulting 

from more tonnage from the proposed one hectare extension will be no more 

than minor over and above the existing tonnage. 

4.5.9 There would be no additional traffic associated with the loading/ unloading 

activities of vessels and trucks servicing the area of the farm extension, as the 

applicant would be utilising existing vessels/ trucks and other services, as 

currently used to service the existing farm. Therefore, residents close to the 

wharf and visitors to it will not be adversely affected by the activities associated 

with the proposed one hectare extension. It is noted that the traffic and wharf 

activities that were anticipated by the Area B applications were of no concern to 

NZ Transport Authority nor to Thames Coromandel District Council. It is therefore 

concluded that the effects from the 1 hectare extension being applied for would 

also be acceptable to both organisations. 

4.5.10 The applicant therefore considers that the existing facilities are available to and 

can adequately be used for servicing the one hectare marine farm extension, 

given that the applicant is an existing operator and will be utilising existing vessels 

and existing trucks, and there is an existing wharf management protocol in place. 

4.5.11 The applicant notes that the Hauraki-Coromandel Development Group and 

Thames Coromandel District Council is currently working on future wharfing 

infrastructure requirements to support the Coromandel aquaculture industry. 

Likewise Waikato Regional Council aims to address this matter in accordance with 

its Regional Land Transport Strategy 2011 - 2041, along with policy work relating 

to aquaculture growth in the region. It is clear that a strategic approach to 

planning for aquaculture infrastructure (as anticipated by the above work) is 

taking place and should occur independently of this application. 

2 Te Kouma Sugar Loaf Landing Facility Coromandel Harbour: Operational Management Plan 1993 & draft 2011 

3 Dunbar-Smith, B., for the Hauraki Coromandel Development Group, 2010.Wharfing Infrastructure Discussion Document, p18 

4 Ibid, pp 6, 24 

10

4.6 Any discharge of contaminants into the environment, including any unreasonable 

emission of noise and options for the treatment and disposal of contaminants 

11 

4.6.1 The discharges associated with mussel farming include pseudofaeces and “dropoff” 

(shells, sediment and other marine life) resulting from cultivation and 

harvesting processes. These are discharges which are covered by Rule 16.5.5A of 

the RCP and for which consent is sought. The effect of the discharges on the 

benthic ecosystem is covered in the scientific report attached in Appendix 2. 

4.6.2 Compliance with the Mussel Industry’s Code of Practice will ensure that there is 

minimal overboard loss of non-biodegradable or other waste materials. Regular 

maintenance checks of the farms would also be undertaken to ensure security of 

the high economic investment in the structures. Any waste rope would be taken 

to shore for land disposal. Any bio-fouling on lines or mussels is generally 

removed as a part of the harvesting process, and therefore returned to the 

marine area. 

4.6.3 There will be no unreasonable emissions of noise from the proposed activity. The 

only noise resulting from the activity would be from the barges and harvesting 

equipment and will therefore be intermittent and seasonal. There would only be 

a minor increase over and above the existing consented operations. 

4.7 Any risk to the neighbourhood, the wider community, or the environment through 

natural hazards or the use of hazardous substances or hazardous installations 

4.7.1 The relevance of the above factors to this application is in respect of: 

(i) potential hazardous installations in the form of the longlines and 

navigational equipment and the potential, albeit minimal, resulting 

hazard to marine users; and 

(ii) the effects of natural hazards, in the form of adverse weather conditions, 

or changes in sea level 

(iii) refuelling of vessels at Te Kouma wharf. 

4.7.2 The proposed longline structures would be secured to the ocean floor by screw 

anchors at each end of each mussel line. The proposed anchor types do not pose 

any threat to vessels, as they are approximately 6 metres below the surface. 

4.7.3 Sufficient room between mussel lines will be left in order to provide safe 

navigable channels for small vessels and service vessels. Accordingly, it is 

anticipated that commercial and recreational vessels that are under competent 

control will still be able to utilise the waters of the area and navigate freely 

between the marine farm lines without undue risk, and to pass around the farm 

block, including in adverse weather conditions. 

4.7.4 To avoid a hazard to users of the CMA, the applicant will ensure that the lighting 

system is extended to incorporate the proposed extension area (ie corners B & F 

11

12 

in Appendix 1 and designed in accordance with Maritime New Zealand’s 

“Guidelines for Aquaculture Management Areas and Marine Farms 2005). Lights 

would be regularly maintained. 

4.7.5 The lights will be yellow and set to flash 5 times every 20 seconds. They will be 

visible to 1 nm and stand 1m above sea level, as per Maritime NZ requirements. 

4.7.6 Technological changes in recent years in terms of anchoring and type of ropes 

used and changes in farming practices have significantly reduced the occurrence 

of breakages, particularly during storm events. Should there be a rope break, 

however, there would be no impacts on other farms, due to the distance to the 

nearest other farm. Due to the cost of equipment, the applicant would seek to 

secure/ recover any damaged gear as soon as possible, thereby also avoiding any 

navigation concerns. In addition, the farms will be regularly maintained to ensure 

security of lines and buoys. 

4.7.7 There will be no hazardous substances used by the farmers in exercising the 

consent applied for by this application. However it is noted that vessels servicing 

the farm area would undertake refuelling at Sugar Laof or Coromandel wharves. 

At both of these locations authorised pumps and refuelling systems are in place, 

including oil spill response planning. Vessel skippers have been trained in the safe 

use of the refuelling equipment. 

4.7.8 Sea level rise is unlikely to have any significant impact on the marine farms 5 . The 

structures are floating and will be adjusted over time to any change in sea levels. 

4. Description of mitigation measures 

4.1 A description of the mitigation measures (safeguards and contingency plans where 

relevant) to be undertaken to help prevent or reduce the actual or potential effects of the 

proposed activity is required to be provided by the RMA. 

4.2 The applicant would operate the proposed extension in a sound commercial manner and 

in compliance with the standards identified in the Mussel Industry Code of Practice. 

These standards are designed to ensure efficient management of the farm and the 

production of high quality stock, to ensure long term financial viability and environmental 

sustainability. It is noted that farmers are audited by Aquaculture New Zealand in respect 

of implementing this Code of Practice. 

4.3 The applicant would comply with the Te Kouma Sugar Loaf Landing Facility Operational 

Management Plan. This management plan addresses all potential effects of using the 

5 Ministry for the Environment, 2008. Coastal Hazards and Climate Change. A Guidance Manual for Local Government in New 

Zealand. 2 nd edition. Revised by Ramsay, D and Bell, R. (NIWA). 

12

13 

Sugar Loaf wharf through management of activities such as vehicle movements, parking, 

storage of equipment and noise. 

4.4 The proposed navigation aids will adequately mitigate any potential impacts on 

navigation. 

4.5 A rigorous maintenance regime will be undertaken to ensure the security of the 

structures as the cost of lost and damaged lines, buoys and mussel product is 

economically significant. 

4.6 In respect of Exotic Disease Management, while it is recognised that the presence of an 

algal bloom will impact on harvesting, it is almost always only toxic to humans and almost 

never would it kill any stock on the lines. It is also to be noted that the Mussel Industry 

Council has developed a draft plan to guide response to exotic diseases. This plan meets 

the requirements of MAF Biosecurity for controlling the potential spread of exotic 

diseases in the aquaculture industry. The applicant would fully co-operate with the 

implementation of this plan. (Ref: NZ Mussel Industry Council Ltd, 2004. Exotic Disease 

Response Plan. Draft Version 1). In addition it is noted that the Aquaculture Industry is 

developing a Mussel Industry Biosecurity Contingency Plan. In the event of any incursion, 

both these documents would be drawn upon in any response. 

5. Consultation 

5.1 No consultation has been undertaken in respect of the proposed extension to the existing 

farm. It is relied on that the provisions of the legislative changes and the amendments to 

the RCP would have publicly heralded the application. 

5.2 It is submitted that neither tangata whenua nor any other people would be adversely 

affected by the proposed extension, given the existing use of the area as a marine farm. 

6. Monitoring 

6.1 The RMA requires a description of the monitoring that would be undertaken, where the 

scale or significance of effects is such that monitoring is required. The applicant does not 

consider the effects would be significant (based on the scientific information in Appendix 

2). 

6.2 The baseline survey submitted with the AEE shows that the site is not located over any 

sensitive substrates, and being a standard farm is likely to show similar effects as per 

other sites monitored in the Coromandel area. Measuring any effects from the 1 ha 

extension would be considerably impacted by the larger adjacent farmed areas. It is 

therefore contended that the need for a monitoring plan is not appropriate. 

6.3 The applicant currently participates in mandatory water quality monitoring programmes. 

13

7. Relevant Planning Provisions 

14 

7.1 In accordance with s104(b) of the RMA, this part of the application sets out the relevant 

planning framework. With respect to this application, the activity is classified in the RCP 

as a discretionary activity. 

National Policy Statements 

7.2 There are two national policy statements which are relevant to the application. 

7.3 Firstly, the NZCPS (2010) includes a specific policy referring to marine farming which 

states: 

Policy 8: Aquaculture 

Recognise the significant and existing potential contribution of aquaculture to the 

social, economic and cultural well-being of people and communities by: 

(a) including in regional policy statements and regional coastal plans 

provision for aquaculture activities in appropriate places in the coastal 

environment, recognising that relevant considerations may include: 

(i) the need for high water quality for aquaculture activities; and 

(ii) the need for land-based facilities associated with marine farming; 

(b) taking account of the social and economic benefits of aquaculture, 

including any available assessments of national and regional economic 

benefits; and 

(c) ensuring that development in the coastal environment does not make 

water quality unfit for aquaculture activities in areas approved for that 

purpose. 

It is clear that marine farming is an appropriate use of the CMA, and that it would 

contribute significantly to the economic, cultural and social well-beings of the region’s 

communities. Provision for farm extensions has been included in the RCP. It is 

considered that the application is consistent with the 2010 NZCPS. 

7.4 Secondly, sections 7 and 8 of the Hauraki Gulf Marine Park Act 2000 have the effect of 

an NZCPS. This Act promotes a co-operative approach to the integrated and sustainable 

management of the Hauraki Gulf. This Act recognises the importance of the Hauraki 

Gulf and the diversity of the marine ecosystem and the wide values and uses people 

have of the area. 

7.5 Section 7 recognises the national significance of the Gulf and emphasises the lifesupporting 

capacity of the Gulf and in particular identifies that this: 

“…includes the capacity - 

(a) to provide for the … relationship of the tangata whenua of the Gulf with the 

Gulf … and the … wellbeing of people and communities, 

14

15 

(b) to use the resources of the Gulf …for economic activities and recreation…and 

(c) to maintain the…water and ecosystems of the Gulf”. 

It is considered that the application is consistent with these directives. 

7.6 Section 8 identifies management objectives. These relate to a range of environmental, 

Maori and community matters, all of which have been addressed in this application. The 

protection of kaimoana is one objective, and based on the assessments referred to in this 

AEE, there will be no adverse effects on this resource as a result of the application. Subsection 

(e) states: 

“the maintenance and, where appropriate, the enhancement of the contribution of 

the …physical resources of the Hauraki Gulf…to the social and economic well-being 

of the people and communities of the Hauraki Gulf and New Zealand”. 

Marine farming provides an opportunity to enhance the social and economic wellbeing of 

people and communities of the Hauraki Gulf (as discussed in section 4 above). 

7.7 It is considered that this application for a one hectare extension is consistent with the 

directions of this NZCPS, and with the work being undertaken by the Hauraki Gulf Forum. 

Operative Regional Policy Statement 

7.8 The operative Regional Policy Statement (2007) includes a section on coastal 

management in section 3.5. In particular: 

Objective 3.5.4 refers to the preservation of natural character, which is a matter of 

national importance in s6(a) of the RMA. This objective is implemented in particular 

through policies on protection of significant areas, recognition of coastal processes 

and adoption of a precautionary approach. 

Objective 3.5.5 addresses coastal water quality and includes one policy on 

maintaining and enhancing water quality. 

Objective 3.5.6 covers integrated management and is implemented by policies on 

consistent management approaches by different agencies and recognition of Tangata 

Whenua interests. 

Objective 3.5.7 and its related policy cover the maintenance and enhancement of 

public access 

Objective 3.5.8 and its related policy address excessive noise emissions 

7.9 The proposed area that is the subject of this application is consistent with the above 

policy directives. The area is in a locality where marine farming is already being 

undertaken and the additional impact on natural character of the additional 1 ha area 

would be negligible. Marine faming requires high quality water quality in order to meet 

food and health standards. The activity within the area being applied for would not 

degrade existing water quality. The need for integrated management is recognised and 

15

16 

the applicant is a member of the industry in the Coromandel, working with different 

agencies involved in aquaculture and support requirements. Public access is not 

restricted through the area subject to this application. The activities on the 1 hectare area 

being applied for would not generate excessive noise. The associated vessel operations 

are also not considered to be excessive. 

Proposed Regional Policy Statement 

7.10 The proposed Waikato Regional Policy Statement (2010) has a range of objectives and 

policies that support this application. In particular, there is one Objective and two policies 

that are particularly relevant: namely 

Objective 3.6: Coastal Environment. This objective highlights the need for integrated 

management and the protection of unique values and the avoidance of conflicts 

between uses and values. 

Policy 7.1: Interests in the coastal marine area: This policy recognises the coastal 

marine area as being public space and the need to allocate space to different 

activities. It has two key implementation methods relating to allocation of space and 

an aquaculture strategy. 

Policy 7.2: Marine Water Quality: This policy seeks to maintain or enhance water 

quality. It includes a method recognising the importance of improving water quality. 

The proposed RPS anticipates that aquaculture is an appropriate use in the CMA for 

environmental, social, economic and cultural well-beings. Method 7.1.4 combined with 

the recent legislative and RCP changes recognise that the one hectare extension to 

existing farms would be an appropriate development in the coastal marine area. This 

application is therefore consistent with the directions of the proposed RPS. 

Waikato Regional Coastal Plan 

7.11 The RCP is the most relevant planning instrument to this proposal, in that it specifically 

addresses extensions to existing farms. Within the RCP a marine farming extension is 

identified as being a discretionary activity. 

7.12 The Issue, Objective and Policies in Chapter 6 of the plan support the further development 

of marine farming. Marine farming is recognised as an important industry within the 

Waikato region. There is also an emphasis on sustainable management and efficient use 

of space. This application is consistent with the directions of the RCP. Specific provisions 

are discussed below. 

Objectives and Policies 

7.13 Chapter 6 of the plan addresses marine farming. The introduction recognises the 

importance of the Firth of Thames and Coromandel areas for marine farming. It also 

recognises the potential for new technologies and the contribution this makes to the 

social and economic future of the area. It is noted that this has been supported through 

the report: “Economic Impact of Coromandel Aquaculture”, Wyatt, S., 2011. 

16

7.14 Objective 6.1 states: 

Marine farming developed in an efficient and sustainable manner which avoids 

adverse effects on the coastal environment as far as practicable. 

17 

It is considered that the application for a one hectare extension is consistent with and 

meets the above objective and that the application is planned to be managed in a manner 

to ensure the efficient use of space and efficiency in the operation of the farm. 

7.15 Policy 6.1.1 – (Marine Farming Structures) states: 

Take a precautionary approach to marine farm development by ensuring that the 

erection, placement, use of, and occupation of space by any marine farm structure in 

the coastal marine area avoids as far as practicable any adverse effects (including 

cumulative effects) on the coastal environment. Where complete avoidance is not 

practicable, adverse effects should be remedied or mitigated. 

This policy is an enabling and precautionary policy which recognises that erecting and 

using structures are a required part of marine farming. The farming structures proposed 

will be an extension to an existing farm. The effects of the proposed structures are 

considered to be acceptable as discussed above. This application meets the policy 

directive. 

7.16 Policy 6.1.1c – (Extensions to Marine Farms) states: 

Where assessment shows that the adverse effects of an authorised marine farm 

are not significant, provide for small extensions that: 

a) avoid adverse effects on areas of ecological significance; 

b) maintain access to the shoreline from the coastal marine area; 

c) maintain navigational safety and recreational values; 

d) maintain natural character and amenity values. 

The policy specifically provides for small extensions to existing farms. This application 

meets the policy directive, as discussed in sections of the AEE above. 

7.17 Policy 6.1.2 – (Recreation and Navigation) states: 

Ensure marine farms are located, constructed and maintained in a way which does 

not compromise safe recreation and navigation. 

This application meets this policy directive. A lighting application has been submitted to 

Maritime New Zealand for approval. The applicant will also ensure that an appropriate 

maintenance regime will be undertaken to maintain and service the lights. 

17

7.18 Policy 6.1.3 – (Integrated Management) states: 

Promote integrated management between marine farm operators, relevant 

network utility operators and all agencies with marine farming responsibilities. 

18 

This policy addresses the need for integrated management. The applicant is already a 

part of the existing industry on the Coromandel area and will immediately integrate the 

operations of this application for an extension into their existing activities. This ensures 

maximum efficiency in use of people and facilities within the industry. The applicant is 

aware of the requirements for Maritime NZ approvals; the health and Safety approvals; 

and the “MFish” requirements for the undue adverse effects assessment and Fish serve 

registrations. This application will therefore fit comfortably into the current processes the 

industry has already established, including with relevant agencies, to ensure integrated 

management. 

7.19 In addition, Rule 16.5.5A sets out a range of standards and terms. It is considered that 

this application and the way it would be implemented would meet all the standards and 

terms. 

Information requirements of the plan 

7.20 Appendix 1 and 1A of the RCP sets out a list of information that may be required when 

applying for a coastal permit. The relevant matters have been covered in this application 

in the above sections and as detailed in the following paragraphs. 

7.21 The General information requirements have been addressed throughout this document 

and further in the attached scientific report. It is submitted that any cumulative adverse 

effects of the proposed activity would be less than minor. 

7.22 The matters specific to Marine Farming have been addressed throughout this AEE. It is 

submitted that the effects of marine farming from the one hectare extension are 

anticipated by the plan and will be less than minor. 

7.23 It is considered that all the relevant information requirements set out in Appendix I and 

1A of the plan have been satisfied. 

8. Consent Conditions 

8.1 The term of the consent being sought is for approximately 13 years – to enable the term 

of the extension area which is the subject of this application, to be made concurrent with 

the term of the existing marine farm (which expires on 1 January 2025). 

9. Notification 

9.1 The applicant requests that the application be processed as a non-notified application. 

The plan is silent in terms of notification and the application is for a discretionary activity. 

9.3 The Council must publicly notify an application if the effects will be or are likely to be 

more than minor, a rule in a National Environmental Standard (‘NES’) requires it to be 

18

19 

publicly notified, or the applicant requests that it be publicly notified. In determining 

whether adverse effects are likely to be more than minor, effects on owners or occupants 

of the subject or adjacent land must be disregarded. 

9.4 In this case, there is no NES which requires the application to be publicly notified and the 

applicant does not request that the application be notified. Based on the analysis in this 

AEE and relevant reports on effects, it is contended that the effects of the proposal will be 

less than minor. It is considered that the Council has sufficient information regarding the 

impacts of marine farming in the proposed area of the extension. Therefore, it is 

contended that public involvement is not warranted from either a public interest or 

information perspective. 

10 Conclusions 

10.1 The key points of this application for a one hectare extension are: 

The extension is located adjacent to and contiguous with the applicant’s existing 

marine farm LI 373. 

The one hectare extension has been provided for in the RCP in rule 16.5.5A. 

The application meets the standards and terms of Rule 16.5.5A. 

Based on the scientific report submitted in support of the application, the 

environmental effects of developing the one hectare extension are considered to 

be acceptable and adverse effects will be less than minor. 

The application represents efficient use of the CMA and will enable the local 

marine farming industry to grow and will result in positive effects on the 

economic and social wellbeing of the local communities. 

This application is consistent with the Government’s Aquaculture directives, the 

NZCPS 2010, and the objectives and policies of the proposed RPS and RCP. 

The matters in Rule 16.5.5A and Appendices 1 and 1A of the RCP have been 

covered and the extent to which the proposed one hectare extension would 

change the effects over and above the existing use has been identified as being 

negligible. 

10.2 It is therefore considered that the application warrants consent and need not be notified. 

19

Appendix 1: Survey plan showing location of the farm and 

proposed extension 

20 

20

21 

Appendix 2: Short Report - Coromandel Mussel Farm Extension – 

LI 373 

21

REPORT NO. 2167 

COROMANDEL MUSSEL FARM EXTENSION - 

BENTHIC SURVEY ASSESSMENT FOR LI 373


COROMANDEL MUSSEL FARM EXTENSION - 

BENTHIC SURVEY ASSESSMENT FOR LI 373 

DANA CLARK, DAVID TAYLOR, ERIC GOODWIN 

Prepared for Gold Ridge Marine Farm Limited. 

CAWTHRON INSTITUTE 

98 Halifax Street East, Nelson 7010 | Private Bag 2, Nelson 7042 | New Zealand 

Ph. +64 3 548 2319 | Fax. +64 3 546 9464 

www.cawthron.org.nz 

REVIEWED BY: 

Robyn Dunmore 

APPROVED FOR RELEASE BY: 

Rowan Strickland 

ISSUE DATE: 30 May 2012 

RECOMMENDED CITATION: Clark D, Taylor D, Goodwin E. 2012. Coromandel Mussel Farm Extension - Benthic Survey 

Assessment for Li 373. Prepared for Gold Ridge Marine Farm Limited . Cawthron Report No. 2167. 5 p. plus appendix. 

© COPYRIGHT: Apart from any fair dealing for the purpose of study, research, criticism, or review, as permitted under the 

Copyright Act, this publication must not be reproduced in whole or in part without the written permission of the Copyright Holder, 

who, unless other authorship is cited in the text or acknowledgements, is the commissioner of the report.


1. SURVEY SUMMARY 

A benthic assessment was commissioned by Gold Ridge Marine Farm Limited and 

carried out by the Cawthron Institute (Cawthron) on 14 December 2011, within and 

adjacent to a proposed 1 ha extension at Li 373, SO 56415. 

1.1. Current farm layout 

A consent for Li 373, a 6 ha green-lipped mussel (Perna canaliculus) farm, was issued 

in 1987 and the farm was installed over the following 10 years. It has been used 

exclusively for this purpose since that date. 

Li 373 lies to the east of Moturua Island, to the north of the Coromandel Harbour and 

16 km from the Coromandel Harbour / Sugarloaf Wharf at Te Kouma (Figure 1). The 

farm is at depths ranging between 14-30 m. It is no closer than 45 m from the shore 

and is situated adjacent to mussel farms, Li 396 and Li 361. 

25m 

30m 35m 

45m from 

shore 

Moturua Island 

Li373 

Stocking 

density 

= 11 lines 

5m 10m 15m 

Li396 

0 37.5 75 150 225 300 

m 

20m 

Li396 

± 

Li361 Li361 

Moturuhi 

Is. 

Moturua 

Is. 

30m 





Figure 1. Site map of mussel farm Li 373 showing the location of the current farm (surface 

structures), the currently consented area and the proposed farm extension. The current 

farm areas (surface structures) of the neighbouring mussel farms, Li 396 and Li 361, are 

shown in grey. Bathymetry is indicated by blue shading and depth labels. Inset shows the 

location of the farm within the wider northern Coromandel area. 

30m 

1


2 

Li 373 is currently farmed in two blocks of 11 x c.150 m floated backbone lines per 

block and is stocked with mussels of varying growth stages. No lines have been used 

for spat catching. 

Based on the assessment done on 14 December 2011, and the area of farm surface 

structures was mostly contained within the consented area. 

1.2. Benthic assessment methods 

The benthic assessment was carried out using video transects and a grab sample 

within and adjacent to the proposed extension and currently farmed area (Figure 2). 

± 

T5 

Inshore west 

Li373 

0 25 50 100 150 200 

m 

South 361 north 396 

Li396 

T6 

Li361 

Li396 

361 north 

Sediment Key 

Li361 

South 361-396 


Gravel 

Sand 

Silt & clay 



Mussel extent 


Figure 2. Map of mussel farm Li 373 showing the location of the current farm (surface structures) 

and proposed farm extension, the estimated extent of mussel shell clumps beneath the 

farms, video transect locations and grain size at the sediment grab station. The current 

farm areas (surface structures) of the neighbouring mussel farms, Li 361 and Li 396, are 

shown in grey.


Mussel shell drop-off is commonly used an indicator of the extent of benthic effects 

beneath mussel farms (Wong & O’Shea 2011), and video transects were used to 

determine the limits of mussel shell drop-off and/or mussel clumps on the seabed 

around the block of farms. Li 373 is situated adjacent to Li 396 and Li 361 and the 

extent of mussel shell drop-off was determined around the entire block of farms. An 

underwater video camera and light was attached to a sled and tethered via cables to a 

VCR and television on the boat. Six transects (Figure 2) were undertaken by lowering 

the sled and camera to the seabed and towing it in the required direction. GPS 

positions were recorded for each transect with observations of conspicuous epifauna 

and substratum type. 

A single grab sample was collected from t outside the southwest corner of the farm 

using a 0.01 m 2 van Veen grab sampler. A 63 mm diameter core sub-sample was 

photographed and the top 25 mm was collected for analyses of sediment grain size. 

Grain size was determined gravimetrically after separation of fractions by wet sieving 

and drying at 105°C, for gravel (≥ 2 mm), sand (≥ 63 μm - < 2 mm) and silt/clay (< 63 

μm) size classes. 

Depth profiling was undertaken to assist in characterising the seabed. Continuous 

depth readings from a Garmin F100 depth sounder within and adjacent to the farm 

areas, and were sent to a PC via a RS232 serial output. The PC simultaneously 

collected separate RS232 serial output of latitude and longitude from a GPS, and both 

data streams were incorporated using communications software. Depths were 

standardised to chart datum and plotted as depth contours in ArcMap. 

1.3. Benthic assessment results 

Video transects along the perimeter of the farm revealed mussel clumps, mussel shell 

drop-off and a fine covering of shell hash overlying mud (e.g. Appendix photographs 1 

and 7). A patchy film of orange/brown benthic diatoms was present in some mud 

areas (Appendix photograph 2). Conspicuous epifauna included cushion stars 

(Patiriella sp.), ascidians (Styela clava), eleven-armed sea stars (Coscinasterias 

muricata), sea cucumbers and small feather hydroids. Two horse mussels (Atrina 

zelandica) were observed along the inshore transect. Burrows in the mud were 

common, suggesting that regular bioturbation occurs over the site. 

Other transects around this block of farms have shown a similar environment of 

mussel clumps and shell drop-off on mud (e.g. Appendix photographs 9 and 11); 

therefore, it is likely that this habitat is widespread beneath the farm. Mussel clumps 

and shell drop-off became less dense with distance from the farm. Beyond the mussel 

clump/shell drop-off areas (> 50-115 m north and south of the farm; > 20 m inshore of 

the farm) the substratum was mud, often covered with shell hash, with few epifauna 

present (Appendix photographs 2 and 6). 

3


4 

The sediment at the southern edge of the farm was primarily gravel (57.6% silt and 

clay) with some sand (19.7%) and silt and clay (22.6%) present (Figures 2 and 3). The 

high gravel content is consistent with the fine covering of shell hash observed in some 

areas around the farm. The sediment core was a uniform grey brown colour with shell 

hash/gravel visible and no obvious apparent redox potential discontinuity (aRPD) 

layer (Figure 3). 

Figure 3. Photograph of the sediment core from mussel farm Li 373. 

2. CONCLUSION 

The benthic environment observed under the current farm and the proposed 

extension was typical of the modified benthic habitats found beneath inshore mussel 

farms throughout the Coromandel (Taylor et al. 2012). The area was characterised by 

areas of increased mussel shell cover and greater abundances of associated 

epifauna. Site-specific factors such as water currents and substratum type are known 

to influence the depositional effects of mussel farms on the benthic environment 

(Hartstein & Stevens 2005, Giles et al. 2006), but the extent of effects can largely be 

determined by the limits of the mussel shell drop-off (Wong & O’Shea 2011). 

The main findings of the benthic assessment were: 

1. Mussel clumps and shell drop-off were the most conspicuous changes to the 

benthic environment. This extended approximately 50-115 m north and south of


the farm, but only 20 m inshore of the farm and it did not encroach on inshore 

habitats. 

2. Occasional horse mussels were observed along the inshore boundary of existing 

farm which suggests that, beyond mussel clump/shell drop-off areas, this 

species can survive in relatively close proximity to mussel farms. The proposed 

offshore extension of the farm will be greater than 100 m from where the horse 

mussels were observed and, therefore, the extension is highly unlikely to have 

any direct effects on the local population. 

3. The benthic environment within the proposed 1 ha extension area has already 

been partially affected by mussel clumps/shell drop-off. Therefore, any effects 

from the proposed extension are likely to be no more than minor, with the net 

result being a possible increase of the area affected by clumps/shell drop-off in 

an alongshore direction. 

4. This is likely to result in no more than minor and reversible changes to the 

benthic environment and to associated epifauna and infauna communities. 

5. These effects are placed into a broader context in a wider-scale assessment of 

effects (Taylor et al. 2012). 

3. REFERENCES 

Giles H, Pilditch CA, Bell DG. 2006. Sedimentation from mussel (Perna canaliculus) 

culture in the Firth of Thames, New Zealand: Impacts on sediment oxygen and 

nutrient fluxes. Aquaculture 261:125-140. 

Hartstein ND, Stevens CL. 2005. Deposition beneath long-line mussel farms. 

Aquaculture Engineering 33:192-213. 

Taylor DI, Clark D and Keeley N. 2012. Assessment of Benthic and Water Column 

Effects from Inshore Coromandel Mussel Farms. Prepared for a collective of 

Coromandel Mussel Farmers. Cawthron Report No. 2134. 31 p. plus 

appendices. 

Wong KLC, O’Shea S. 2011. The effects of a mussel farm on benthic macrofaunal 

communities in Hauraki Gulf, New Zealand. New Zealand Journal of Marine 

and Freshwater Research 45(2): 187-212. 

5


4. APPENDIX 

Appendix 1. Seabed transect samples from beneath Li 373 and the neighbouring farms. 

6 

1 2 

3 4 

5 6 

7 8


9 10 

11 12 

13 14 

15 16 

7

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Application 124771 - Ministry of Fisheries

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