Impacts of biodeposits from suspended mussel (Mytilus edulis L.) culture on the surrounding surficial sediments

The effects of increased sedimentation on the macrobenthic community physic al structure, and biogeochemistry of the surficial sediment around two farm s in southwest Ireland were examined in conjunction with current characteri stics. Both farms had been in production for over eight years, were of reas onably large size (> 100 MT) and located in low-energy environments. At one site, the benthic community was subjected to bulk sedimentation and organi c enrichment and reduced macrobenthic infaunal diversity and elevated level s of organic carbon were recorded close to the farm. In general, effects we re restricted to a radius of 40 m around the farm. Conversely. at the secon d sits, there were no observed effects of mussel biodeposits on the benthos and a diverse macrobenthic community persisted. We propose that variations in the dispersion of biodeposits caused by local current patterns had a si gnificant influence on the impact observed, and that this could also accoun t for differences reported in other studies. (C) 2001 International Council for the Exploration of the Sea.