Application 124771 - Ministry of Fisheries
Application 124771 - Ministry of Fisheries
Application 124771 - Ministry of Fisheries
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CAWTHRON INSTITUTE | REPORT NO. 2134 MAY 2012<br />
TABLE OF CONTENTS<br />
1. BACKGROUND ................................................................................................................ 1<br />
2. AREA AQUACULTURE HISTORY ................................................................................... 3<br />
3. BACKGROUND TO SEABED AND WATER COLUMN EFFECTS .................................. 4<br />
3.1. Seabed effects ................................................................................................................................................ 4<br />
3.2. Water column effects ...................................................................................................................................... 6<br />
4. METHODS ........................................................................................................................ 7<br />
4.1. Characterisation and mapping <strong>of</strong> the seabed ................................................................................................. 7<br />
4.1.1. Site bathymetry ......................................................................................................................................... 7<br />
4.1.2. Sediment physical, chemical and biological properties ............................................................................. 7<br />
4.2. Water column sampling .................................................................................................................................. 8<br />
5. RESULTS ......................................................................................................................... 9<br />
5.1. Sediment physical and chemical properties ................................................................................................... 9<br />
5.2. Sediment biological properties ...................................................................................................................... 11<br />
5.3. Enrichment stages ........................................................................................................................................ 15<br />
5.4. Epibiota from video transects ....................................................................................................................... 15<br />
5.5. Water column properties .............................................................................................................................. 20<br />
6. DISCUSSION .................................................................................................................. 25<br />
6.1. Benthic effects .............................................................................................................................................. 25<br />
6.2. Water column effects .................................................................................................................................... 26<br />
6.3. General conclusions ..................................................................................................................................... 28<br />
7. REFERENCES ............................................................................................................... 30<br />
8. APPENDICES ................................................................................................................. 32<br />
LIST OF FIGURES<br />
Figure 1. Map showing the eight reference farm sites and the six control sites used in the wider<br />
assessment <strong>of</strong> benthic and water column effects. .............................................................. 2<br />
Figure 2. Summary <strong>of</strong> potential wider ecological effects, localised benthic effects, and water<br />
column effects <strong>of</strong> mussel farming on the environment. ...................................................... 4<br />
Figure 3. Stylised depiction <strong>of</strong> a typical enrichment gradient experienced at low flow sites,<br />
showing generally understood responses in commonly measured environmental<br />
variables. ............................................................................................................................. 5<br />
Figure 4. Average sediment grain-size, total nitrogen and total organic carbon for control and<br />
farm sites to the north and south <strong>of</strong> Coromandel Harbour. .............................................. 10<br />
Figure 5. Average total nitrogen and total organic carbon from reference farms and control sites<br />
to the north and south <strong>of</strong> Coromandel Harbour. ............................................................... 11<br />
Figure 6. MDS (Multidimensional scaling) plot <strong>of</strong> similarity <strong>of</strong> infauna communities between<br />
control and farm sites to the north and south <strong>of</strong> Coromandel Harbour............................. 13<br />
Figure 7. Average enrichment stages from replicate grab samples at control and reference farm<br />
sites. .................................................................................................................................. 15<br />
Figure 8. Representative images captured from video footage from control sites and reference<br />
farm sites. A) Sandy seabed with horse mussels, B) Sand and shell seabed with<br />
mussels and anemone, C) Mud seabed with horse mussel and benthic diatom mat, D)<br />
Mud seabed with mussels and benthic diatom mat, E) Mud seabed, F) Mud seabed<br />
with shell. .......................................................................................................................... 17<br />
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