海州湾春季皮氏叫姑鱼摄食习性的空间异质性及其索饵场分布

鱼类通过摄食维持自身的生存、生长和繁殖,对鱼类摄食习性的空间异质性及其索饵场分布进行研究有助于了解鱼类在不同海域间的生长差异。本研究根据2011年及2013―2016年春季在海州湾进行的渔业资源底拖网调查数据,通过胃含物分析研究皮氏叫姑鱼(Johniusbelangerii)的摄食习性,依据胃含物分析结果选择主要饵料生物,结合皮氏叫姑鱼和主要饵料生物的空间分布,研究皮氏叫姑鱼摄食习性的空间异质性,并判别其索饵场。结果表明:皮氏叫姑鱼摄食的饵料生物共有20余种,其中虾类(IRI%=55.54%)和端足类(IRI%=35.94%)为优势饵料类群。基于胃含物分析和底拖网调查,选择海蜇虾(Latreutesanoplonyx)、细巧仿对虾(Parapenaeopsistenella)、鲜明鼓虾(Alpheus distinguendus)、疣背宽额虾(Latreutes planirostris)、细螯虾(Leptochela gracilis)、戴氏赤虾(Metapenaeopsis dalei)、日本鼓虾(Alpheus japonicus)和中华安乐虾(Eualus sinensis) 8种饵料生物研究皮氏叫姑鱼摄食习性的空间异质性及其索饵场。摄食选择性的研究表明,海州湾春季的皮氏叫姑鱼喜食海蜇虾。本研究发现,皮氏叫姑鱼及其主要饵料生物资源丰度重心均位于海州湾中部10～20m深海域;海州湾中南部10～20m海域的饵料生物资源丰度显著高于其他海域(P0.05),而且该海域皮氏叫姑鱼的个体较小,生长速度较快,摄食强度较高,是其主要的索饵场。

Spatial heterogeneity in the feeding habits and feeding ground distribution of Johnius belangerii in Haizhou Bay during spring

Feeding is an important behavior for the growth and reproduction of fish. The nutrient niches of different areas and the distribution of main feeding grounds can be understood by analyzing the spatial heterogeneity of the feeding habits and growth rates of fish species. Based on samples collected from bottom trawl surveys in Haizhou Bay during the springs of 2011 and 2013-2016, the feeding habits of Johnius belangerii were studied by analyzing their stomach contents. The spatial heterogeneity of feeding habits and feeding grounds was identified by analyzing the distribution of J. belangerii and its major prey species. The results showed that prey items of J. belangerii included 20 species, with decapoda and amphipoda being the most predominant prey taxa. Based on stomach content and bottom trawl survey data, eight major prey items, including Latreutes anoplonyx, Parapenaeopsis tenella, Alpheus distinguendus, Latreutes planirostris, Leptochela gracilis, Metapenaeopsis dalei, Alpheus japonicas, and Eualus sinensis were selected to examine the spatial heterogeneity of the feeding habits and feeding grounds of J. belangerii. The sums of IRI%, W%, and F% for the eight major prey items were 35.95%, 55.67%, and 44.59%, respectively. The spatial heterogeneity of feeding habits indicated that J. belangerii preferred to feed upon L. anoplonyx. Compared with results from previous studies, our results showed that the dominant prey items of J. belangerii had changed; this change was not only affected by the inter-species relationships in the ecosystem, but also by the fluctuation in the abundance of dominant prey items in Haizhou Bay. In addition, according to the abundance of these major prey items, the survey stations were divided into two areas (area I and area II) based on hierarchical cluster analysis. Except for M. dalei and E. sinensis, the abundance of the other six prey items in area I was higher than that in area II. In area I, the body length of J. belangerii ranged from 52 to 125 mm, their average body length was (86.67±0.28) mm, their body weight ranged from 2.15 g to 33.76 g, and their average body weight was (11.94±0.12) g. In area II, the body length of the J. belangerii ranged from 47 to 138 mm, their average body length was (95.80±0.12) mm, their body weight ranged from 1.74 g to 39.59 g, and their average body weight was (14.75±0.05) g. Our results showed that the b value in area I (3.24) was significantly higher than 3 (P<0.05), whereas in area II (2.90) it was significantly lower than 3 (P<0.05). In conclusion, J. belangerii and its eight major prey species were more abundant in the 10~20 m depth sea area in the center of Haizhou Bay; the abundance of prey in the 10~20 m depth sea area in the center and south of Haizhou bay (area I) was higher than that in other areas (P<0.05). The individual J. belangerii in this area were smaller and fast-growing. Therefore, this area was identified as the feeding and nursery ground of J. belangerii in Haizhou Bay during the spring.