Growth of juvenile sea scallops, Placopecten magellanicus, under different culture conditions and swimming frequencies

Hatchery-reared juvenile sea scallops Placopecten magellanicus were grown uncontained on the seabed and suspended in pearl nets at three sites in Lunenburg Bay, Nova Scotia, Canada, between March 1992 and March 1993, Shell and tissue growth rates peaked in mid-summer and decreased to the lowest values in winter, although growth never stopped. Shell growth rates were significantly higher in bottom than in suspended culture during most measurement periods. Mean final soft tissue condition index of scallops in suspended culture was significantly higher than in bottom culture at Site 2. Mean final adductor muscle condition index and mean final whole dry weights of scallops were significantly lower in suspended culture than in bottom culture at Site 2.; The effects of swimming frequency and water temperature on the shell growth, tissue mass and stored energy reserves of juvenile sea scallops P. magellanicus were examined in a factorial laboratory experiment spanning six weeks. Individually tagged scallops of similar initial size were induced to swim to exhaustion at three different swimming frequencies in two different water temperature regimes. Scallops at the higher temperature had significantly higher cumulative shell growth than scallops at the low temperature. Condition index of adductor muscle increased significantly with swimming frequency. Scallops at the higher temperature had a significantly higher mean final condition index of adductor muscle than scallops at low temperature. Scallops at high temperature had significantly higher final total carbohydrate content in the adductor muscle than scallops at low temperature. (Abstract shortened by UMI.)...