Influence of environmental factors on condition index and biochemical composition in Mytilus edulis L. in cultivated-raft system, in two Scottish Sea Lochs
Sedat Karayücel, Ismihan Karayücel
University of Ondokuz Mayıs, Faculty of Fisheries, 57 000 Sinop, TURKEY
Institute of Aquaculture, University of Stirling, Stirling FK9 4LA Scotland, UNITED KINGDOM
The effect of environmental parameters; salinity, temperature, seston, particulate organic matter (POM) and chlorophyll-a (Ch-a) on condition index and biochemical composition of Mytilus edulis L. in suspended raft culture in Loch Etive (LE) and Loch Kishorn (LK) were studied from May 1993 to August 1994. The condition indices: wet meat volume condition index (CIV) and dry meat weight condition index (CID) and meat yield (MY) of cultivated mussels showed a similar pattern at 2m and 6m at the both sites. CIV was found to be 41.82% and 57.15% while CID was 9.77 and 12.54 in LE and LK respectively. Site, but not depth had a significant effect on the condition indices, with the latter being significantly higher in LK than LE (P˂0.05). Mainly condition of mussels was affected by temperature and salinity in LE. However temperature had a main significant effect on condition index in LK. Mean protein was found to be 59.99±1.73% in LK and 56.13±1.85% in LE while mean value of carbonhydrate 29.07±2.58% and 31.16±3.14% in LK and Le respectively. Carbonhydrate had an inverse relationship with protein. Lipid was found to be 9.74±0.3% and 10.6±0.31 while ash values obtained were 8.05±0.44% and 7.36±0.43% in LK and LE respectively. Mean moisture was 79.39±0.74% in LE and 79.17±0.78% in LK. Carbonhydrate and lipid showed a positive relationship while protein and lipid were inversely related. Moisture and ash correlated positively with protein while they had a negative relationship with carbonhydrate and lipid at both sites.
Keywords: Mytilus edulis, environmental factors, condition index, bichemical composition