渤海东部海域秋季底层游泳动物种类组成及群落多样性

根据2014年9月在渤海东部海域(37°40'—38°20'N、120°00'—121°20'E)进行的游泳动物底拖网调查数据,应用相对重要性指数、生物多样性指数、群落结构多元统计分析等方法对该海域游泳动物种类组成及群落多样性特征进行了分析。结果表明:调查海域共捕获游泳动物54种,以头足类枪乌贼(Loliolus spp.)为绝对优势种;游泳动物资源密度为28.82kg/h和5166尾/h。游泳动物种类Margalef丰富度指数(D)的变化范围为1.99—3.67,Shannon-Wiener多样性指数(H')变化范围为0.89—2.28,Pielou均匀度指数(J')变化范围为0.29—0.69。群落结构多元统计分析表明,渤海东部海域游泳动物群落结构以60%的相似性可划分为3个组群:长岛群岛海域组群(A组群)、龙口海域组群(B组群)和蓬莱海域组群(C组群);ANOSIM分析表明,组群之间差异极显著,两两之间差异亦极显著。受增殖放流影响,C组群资源密度和种类多样性均保持较高的水平,而A、B组群人为活动频繁,过度捕捞严重,对海域生态环境和渔业资源整体结构的破坏较大。

Autumnal species composition and community diversity of nekton in the eastern Bohai Sea

The species composition and community structural diversity of nekton was examined in the autumn at 21 stations in the eastern Bohai Sea (37°40''-38°20''N, 120°00''-121°20''E) using bottom trawl surveys. Analyses were performed using an index of relative importance, ecological diversity indices, multivariate analysis MDS, and CLUSTER using PRIMER 6 software and other methods. We identified 54 nekton species:34 fishes, 17 crustaceans and 3 cephalopods, belonging to 23 families and 33 genera. There were 5 dominant species, with Loliolus spp. being the most dominant. There were also 11 relatively dominant species identified, including Konosirus punctatus, Thrissa kammalensis, Chaeturichthys stigmatias, Oratosquilla oratoria, and Portunus trituberculatus. The relative nekton resources were 28.82 kg/kg² and 5166 ind./h, which had a variable spatial distribution. Much of the resource was centralized, with peak densities congregated around the Long Island Archipelago. Mantissa resources were mainly concentrated around the Long Island Archipelago and in the upper waters of Longkou. Stations SL12, SL14, SL15, SL16, and SL17 had the highest biomass, while stations SL03, SL06, SL07, SL09, SL12, SL15, and SL17 had the highest mantissa. Margalef''s species richness index (D), Shannon-Wiener diversity index (H''), and Pielou''s evenness index (J'') of the community structure ranged from 1.99 to 3.67, 0.89 to 2.28, and 029 to 0.69, respectively. The MDS had a stress level of 0.15, which showed that the community structure of nekton in the eastern Bohai Sea Bay can be divided into three groups:the Long Island Archipelago group (Group A), the Longkou group (Group B), and the Penglai group (Group C). Group A included a single station (SL19), group B included stations SL01, SL02,SL04, SL05, SL08, and SL13, and group C included SL03, SL06, SL07, SL09, SL10, SL11, SL12, SL14, SL15, SL16, SL17, SL18, SL20, and SL21. ANOSIM analysis showed that in the winter, species compositions in the three groups were very significantly different(P<0.01, with very significant differences between any two groups (P<0.01). The typical within-group species and discriminating species between groups had a significant influence on the community structure. The typical within-group species of Group A was Loliolus spp., with a 97.45% cumulative contribution similarity rate. For group C, Loliolus spp., Oratosquilla oratoria, Thrissa kammalensis, Chaeturichthys stigmatias, Apogon lineatus, and Palaemon gravieri combined to create a cumulative contribution similarity rate of 91.46%. For Group B, Loliolus spp., Oratosquilla oratoria, Portunus trituberculatus, Trachysalambria curvirostris and Thrissa kammalensis comprised the cumulative contribution similarity rate of 90.50%. The species discriminating between groups A and C were Loliolus spp., Oratosquilla oratoria, Thrissa kammalensis, Chaeturichthys stigmatias, Apogon lineatus, Palaemon gravieri, Engraulis japonicas, Konosirus punctatus and Alpheus japonicas, whose dissimilarity cumulative contribution rate was 91.26%. For Groups A and B, the dissimilarity was due to Loliolus spp., Oratosquilla oratoria, Portunus trituberculatus, Trachysalambria curvirostris, Thrissa kammalensis, and Apogon lineatus, with a cumulative dissimilarity contribution rate of 53.14%. For Groups B and C, the species contributing to the dissimilarity were Loliolus spp., Oratosquilla oratoria, Portunus trituberculatus, Trachysalambria curvirostris, Thrissa kammalensis, Chaeturichthys stigmatias, Apogon lineatus, Palaemon gravieri, Konosirus punctatus and Alpheus japonicus, with a cumulative dissimilarity contribution rate of 90.64%. The division between groups was relatively stable, as the assemblages conformed to the water environments in the different groups. The resource density and species diversity of Group C maintained a high level, due to restocking, whereas the marine ecological environment of Group A and B was damaged by frequent human activities, causing a reduction in nekton size, and leading to low diversity indices and resource density. This study aims to provide a scientific basis for the rational development and protection of nekton resources in the eastern Bohai Sea.