Finfish farming - finding a site
Finding a site for a new fin-fish farm involves the following environmental considerations. Farmed fish use oxygen and release ammonia. Where water movements are weak, the build-up of ammonia and the decrease in dissolved oxygen at a farm can harm fish. Uneaten fish food, and fish faeces, sink to the sea-bed and can harm the animals or seagrass here, as well as releasing gases harmful to fish and humans. The following models can be used to screen sites for these effects before incurring the large costs of an environmental assessment that may be required before planning authorities will consent to your use of a site. They will, typically, tell you the maximum mass of fish that can be stocked in order to avoid environmental problems on the farm scale.
| Environment | Species | Scale | Model ( alphabetical order) |
| Fjords, sea-lochs and voes | Salmon Cod |
A:farm | DEPOMOD MOM |
| Mediterranean open coastal water | Sea bream Sea bass Tuna |
A:farm
B:water body |
KK3D
MERAMOD TRIMODENA |
These models take account of the currents and dispersive properties of the water at the potential site. The best single indicator of a good site (from an environmental perspective) is high dispersion (the result of persistent currents due to tides or wind). A site with poor dispersion or poor flushing, is likely to prove bad for farming as well as likely to suffer obvious environmental impact. Sites that have, or are close to, 'conservation features', are also a poor choice: production may need to be highly constrained to prevent damage to these features, which are exemplified by seagrass meadows or reefs of serpulid worms.
In addition, you should seek an informal interview with the public authorities responsible for consenting site development. They should be able to tell you if there are other environmental matters to be considered. Most states or provinces have aquacultural development plans that (a) specify planning constraints at particular sites, and (b) may direct aquaculture to certain regions or prevent its development in others. In most countries it is the responsibility of the public authorities to plan development on water body and regional scales: aquaculture may be encouraged in some regions, and barred or strongly constrained in others, for a number of reasons in addition to environmental considerations.
