大黄鱼含脂量与肥满度的关系及其在渔业研究中应用的探讨

ON RELATIONSHIP BETWEEN FAT CONTENT AND CONDITION FACTOR OF LARGE YELLOW CROKER AS WELL AS ITS APPLICATION IN FISHERY RESEARCH

本文应用经典的索氏法逐尾地分析了大黄鱼的含脂量,并用每月测定过含脂量的同一批鱼计算了其肥满度,结果表明,二者的季度变化并不一致:肥满度最高在8,9和11月,含脂量在1～3月;后者最低在10～11月,而前者此时却在全年平均水平之上。肥满度和含脂量是两个既有联系又有区别的生物学指标,在讨论中作者强调了含脂量在渔业资源合理利用中的重要意义。

In order to study the relationship between the fat content and the condition factor of large yellow croker, Pseudosciaena crocea (Rich.), all 815 samples of large yellow croker collected off Zhejiang Province in 1961-1962 and January 1975 were analysed by using Soxhelt's method after water-absorption by exsiccated sodium sulfate, and the relative condition factor of such fishes after being analysed their fat content was calculated with the Molozov's formula. The results obtained are as follows. Similar tendencies of seasonal variation existed in fat content and condition factor from January to June, i.e. both of them decrease monthly. However, from July to December they varied so much that the condition factor rises above the mean of year rapidly and the fat content falls below the mean. The fat content in the muscle of large yellow croker is the highest in winter and the lowest in summer (spring spawners) and in November (autumn spawners); the condition factor is the highest in autumn and the lowest in June.The seasonal variations of protein and salt contents are less than that of water and fat in most fishes, a result probably from the metabolism of fat and water in different season. It will be seen from this that the fat content and the condition factor are two different biological indices, which should not be lumped together. Attention should be paid to fat content for rational use of fishery resources.