高盐水体消长与冬季带鱼汛期渔场形成的关系

Relations between Dynamics of High-salinity Water Masses and Formation of Fishing Grounds of Cutlass Fish in Winter Fishing Season

本文在分析了1976—1985年浙江近海渔场盐度资料后得出:汛前至汛初(8—11月)高盐水体的消长趋势具有转弱、稳定、强化三种类型。渔汛期间(11—12月)高盐水体类型转换相对较少,但据年际势力强弱差异,又可定量划分为偏弱年、偏强年和常年三个等级。高盐水体强弱在一定程度上能起阻碍鱼群南移的作用,两者关系表现为:1.偏弱年,带鱼汛转旺期提前,中心渔场偏南,汛期进展快。2.偏强年,带鱼汛转旺期推迟,中心渔场偏北,汛期进展缓慢。3.常年,带鱼汛转旺期、中心渔场及汛期进展亦近常年。

The data used in the paper were collected from the offshore fishing grounds of Zhejiang Province during the period of 1976-1985, and were obtained through definite integral calculation. During pre-and early fishing season (August-November), the trend of high-salinity water mass dynamics has three types, weakening, stabilizing and strengthening types. In the main fishing-season (November-December), their exchanges are relatively less. The water masses in each particular year can be classified quantitatively as weak, average and strong grades acccording to their strength. The strength of high-salinity water mass, to a certain extent, can stop fish shoals from migrating southward. Therefore the relations between the strength of water masses and fishing grounds (as well as fishing seasons) are: 1. As for the weak strength water mass, the relation expresses as moving up the main fishing season, shifting central fishing ground to the south, speeding up the fishing season to come to an end; 2. As for the strong strength water mass, it expresses as post-poning the main fishing season, shifting central fishing ground to the north, prolonging the fishing season; 3. As for the average strength water mass, it expresses as average year in these aspects mentioned above.