Report No SR 97(06)F

Feb 1998

A study to investigate the effectiveness of various fish farm monitoring techniques was commissioned by SNIFFER in June 1996. Areas around fish farms on Loch Spelve (marine) and Loch Earn (freshwater) were surveyed in July 1996. Five stations were sampled on each of two transects. Reference stations away from the cages were also sampled. The main techniques compared were benthos sampling, sediment profile imagery (SPI) underwater video and still photography and redox. In addition, various chemical determinands were also measured.

On the marine study, video, photography, benthos and SPI all detected the effect of organic enrichment, but the analysis of the benthos was found to be most effective. Analysis of the benthic data using the Infaunal Trophic Index (ITI) was found to be particularly useful in detecting low level organic enrichment. On the freshwater study, the benthic data were found to be the most effective for monitoring organic enrichment. Underwater photography or video was found to be useful, but only for the detection of gross pollution. Environmental Quality Standards (EQS's) were proposed, along with procedures for future monitoring.

Fish Farm, Monitoring, Benthos, Sulphides, Zinc, Copper, Underwater Photography, Underwater Video, Sediment Profile Imagery, Redox, Diversity Index, Infaunal Trophic Index.

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