ESTIMATING THE CARRYING-CAPACITY OF MUSSEL RAFT SYSTEMS IN 2 SCOTTISHSEA LOCHS

Two different carrying capacity models were applied to commercial muss el raft systems in two sea lochs on the west coast of Scotland. The me an currents were found to be 0.052 m/s in Loch Etive (LE) and 0.05 m/s in Loch Kishorn (LK). The mussel filtration rate ranged from 0.54 to 2.26 l/h in LK and 0.93 to 2.07 l/h in LE (p>0.05). The assimilation e fficiency was 19.64% in May and 25.02% in August in LK (P>0.05). Howev er, the assimilation efficiency was significantly higher in May (28.23 %) than August (21.17%) in LE. Based on the seston clearance model, th e carrying capacity was estimated to be 5.7 times greater in LE than t he present mussel culture system utilitizes, while the carrying capaci ty was about 3 times greater in LK than the present culture system uti lizes. According to the particulate organic matter model, the Loch Kis horn mussel farm is producing more mussels than the estimated carrying capacity of the system (by a factor of 20-40%),while, in contrast, th e mussel production in Loch Etive is considerably below the carrying c apacity (by about 40% to more than 100%). The production capacities we re found to be more accurate in the particulate organic matter model t han in the seston based model at both sites.