Fish farm environmental impacts

All farms must meet strict guidelines to ensure that the environmental impacts are assessed and managed safely.

Nutrient hotspots surveys


The UK has given a commitment to the Oslo and Paris Commission OSPAR EUC to undertake a hotspot area analysis of parts of the west and north coasts of Scotland where fish farming is practised. Using a mechanism for calculating the Equilibrium Concentration Enhancement (ECE) of nutrient nitrogen arising from fish farms, 111 sea lochs have been ranked according to their degree of utilisation for fish farming in relation to the rate of exchange of water with open coastal waters. Project AE11p constitutes an intensive field sampling programme to provide data to enable assessment of the areas selected in relation to OSPAR eutrophication assessment criteria.


  • To conduct seasonal surveys at selected sea lochs impacted to varying degrees by nutrient releases from fish farming activity
  • To measure the following parameters at multiple stations in each loch: CTD, nutrients, chlorophyll a and phytoplankton species composition
  • To collect surface sediment samples from the vicinity of a fish farm with recent use of cypermethrin treatments
  • To collect Fucus growing tips from the shoreline for nitrogen isotopic ratio determination
  • To sample surface sediment by day grab at selected distances from farms for microbial community analysis


Two seasonal cruises have been completed (March/April and August/September 2002) during which hydrographic and biological data were collected at a series of sea lochs and voes on the west and north coasts of Scotland. Results are currently under analysis. Project results will ultimately be included in a report for EPU scheduled for April 2003.

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