黄海中南部鯷鱼各发育阶段对浮游动物的摄食

Studies on the feeding of anchovy (Engraulis japonicus)at different life stages on zooplankton in the Middle and Southern Waters of the Yellow Sea

对 1 999～ 2 0 0 1年在黄海中南部采集的鱼(Engraulisjaponicus)消化道进行了分析。产卵场的鱼仔稚鱼和越冬场的成鱼都是主要在白天摄食 ,胃饱满指数白天明显高于夜间。鱼消化道中的食物团几乎全部由浮游动物组成。鱼偏好的食物随鱼长度的增加而变化。桡足类和它们的卵子、幼体是最大的优势类群。体长小于 1 0mm的鱼仔稚鱼主要摄食桡足类的卵和无节幼体 ;体长 1 1～ 2 0mm的鱼仔稚鱼主要摄食桡足类的桡足幼体和原生动物 ;叉长 2 1～ 30mm的鱼主要摄食纺锤水蚤等小型桡足类和甲壳类的蚤状幼体 ;叉长 41～ 80mm的鱼主要摄食桡足类的桡足幼体 ;叉长 81～ 90mm的鱼主要摄食中华哲水蚤和桡足幼体 ;叉长 91～ 1 0 0mm的鱼主要摄食中华哲水蚤、胸刺水蚤、真刺水蚤等较大的桡足类 ;叉长 1 0 1～ 1 2 0mm的鱼主要摄食中华哲水蚤、胸刺水蚤、太平洋磷虾、细长脚 ;叉长大于 1 2 1mm的鱼主要摄食太平洋磷虾和细长脚鯷。

The gut contents of the fish samples collected in the Middle and Sout hern Waters of Yellow Sea during the period of 1999～2001 were analyzed.As analy zed, the feeding activities of japanese anchovy larval in the spawning g round and adult in the wintering ground mainly took place in the daytime The g u t fullness index in daytime is evidently higher than that in nighttime. The food in the guts almost consisted of zooplankton. The food preference of anchovy cha nged with fish sizes. Copepoea,together with their eggs and larvae, were the mo st dominant preyed items.Anchovy with a body length range of 0～10 mm chiefly pre yed on eggs and nauplius of copepoda,anchovy with a body length range of 11～20 mm chiefly preyed on copepodites and protozoa.The anchovy with a fork le ngth rang ed from 21～30 mm mainly preyed on those small-sized copepoda like Acartia spp. a nd crustacean larvae. The anchovy with a fork length of 41～80 mm did feed on co p epodites, but the anchovy with a fork length of 81～90 mm did feed on Calanus sin icus and copepodites.Those large-sized copepoda such as Calanus sinicus,C entropages spp.and Euchaeta spp. were chiefly fed by anchovy with a fork length rang ed from 91～100 mm. The anchovy with a fork length range of 101～120 mm mainly p reyed on not only the large-sized copepoda like Calanus sinicus and Centr opages spp . but also Euphausia pacifica and Themisto gracilipes, while the anchov y with a fork length above 121 mm dominantly preyed on Euphausia pacifica and Themi sto gracilipes.