Ecasa Toolbox

Fin-fish farming: finding a site

Finding a site for a new fin-fish farm involves subjecting potential sites to a series of filters:

    • a geographical filter: a farm needs good access, shelter from wind and waves, and distance from sources of pollution and other water use; see: Environmental Impacts on Aquaculture.
    • a socio-economic filter: it will be easier to gain permission to install a farm in regions where, for example, the public favours fishfarming; see: Socio-economic Indicators.
    • an environmental filter, taking account of matters considered on this page and on the Management for Sustainability page.

 

These considerations interact with public planning. In most European countries it is the responsibility of the public authorities to plan development on water body and regional scales and to licence sites to avoid excessive environmental impact. Aquaculture may be encouraged in some regions, and forbiden in others, for socio-economic or historical reasons as well as environmental concerns.

Aquaculture effects the environment on a number of scales. Here are the main environmental considerations relating to the local (farm scale). 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 environmental aspects before incurring the large costs of an environmental assessment that may be required before planning authorities will consent to your use of a site. The models will, typically, tell you the maximum mass of fish that can be stocked in order to avoid these local environmental problems and hence to ensure sustainability at a site. Unless stated, they require measurements of currents at the potential site. See also: choosing a model.

Model (alphabetical order) Model category: scale and relevance Environment category Fish type for which applicable Tested at ECASA sites:
AutoDEPOMOD A (farm-scale); sea-bed impact enclosed, and open coastal, mesotidal waters salmon, cod no report available
KK3D A (farm-scale); sea-bed effects Mediterranean open waters sea-bream, sea-bass ? no report available
MERAMOD A (farm-scale); sea-bed effects Mediterranean open waters sea-bream, sea-bass, tuna no report available
MOM A (farm-scale); sea-bed and water-column effects enclosed, and open coastal, waters salmon, sea-bass, sea-bream Dalmar, Sounio, Cephalonia, Piran, Porto Ecolo, Bisceglie
TRIMODENA-LPT
TRIMODENA-HYDRO can predict currents
A (farm-scale) and larger scales; sea-bed effects Mediterranean open waters tuna ? no report available

 

The best indicators of a good site (from an environmental perspective) are high dispersion (the result of persistent strong currents) and deep water. A site with poor dispersion is likely to prove bad for farming as well as likely to suffer obvious environmental impact. Particulate material from farms is more likely to accumulate on the sea-bed, and cause undesirable disturbance, in shallow waters. Finally, sites that have, or are close to, publically designated '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.