Impact of starvation on survival, meat condition and metabolism ofChlamys farreri

Abstract

The effects of 60-day starvation on survival rate, condition index (CI), changes of nutrient composition of different tissues, respiration and excretion of scallopChlamys farreri were studied in laboratory from Oct. 17 to Dec. 15, 1997. Two groups (control and starvation with 200 individuals each) were cultured in two 2 m3 tanks, with 31 to 32 salinity water at 17°C. Starvation effects were measured after 10, 20, 40 and 60 days. There was no mass mortality of scallops of the two tanks and survival rates of the control and starvation groups were 93.5% and 92.0%, respectively. Starvation had strong effect on the meat condition of the scallops, especially after 10 days; when relative lipid percentage dropped sharply while relative protein percentage increased. The impact of starvation on the oxygen consumption rate (OCR) and the ammonia-N excretion rate (AER) was obvious. The OCR increased rapidly after 10 days but decreased after 20 days. The AER increased after 10 days and 20 days, but decreased obviously from 20 to 40 days. The O∶N ratios varied to different degrees, and minimized after 20 days. The low O∶N ratios implied that the protein was the main material for the metabolism ofC. farreri.