深圳鹅公湾水域渔业资源季节变动分析

【目的】阐明深圳鹅公湾水域渔业资源的季节变动及其形成原因,为南海近海典型渔业水域渔业资源的可持续利用和管理提供科学依据。【方法】分别于2012年8月(秋季)和12月(冬季)、2013年3月(春季)和5月(夏季)4个季节在深圳鹅公湾水域进行渔业资源拖网调查,对该水域的游泳生物种类组成、资源密度、优势种组成、长度谱和生物多样性进行季节变动分析。【结果】从深圳鹅公湾水域共渔获游泳生物113种,隶属于3纲14目50科78属。其中,夏季游泳生物种类数量最多(61种),秋季最少(53种),春季和冬季均为56种。夏季游泳生物资源密度和尾数密度最低(分别为5959.20 kg/km~2和356.45 ind/km~2),但其鱼类所占比例最高(分别为51.99%和42.19%)。游泳生物长度谱的季节变动表明夏季捕捞强度最小,秋季捕捞强度最大。鹅公湾水域生物多样性指数季节变动明显,Margalef丰富度指数(D')、Shannon-Wiener多样性指数(H')和Pielou均匀度指数(J')的季节变动趋势一致,均表现为夏季春季秋季冬季。【结论】深圳鹅公湾水域游泳生物资源种类、生物量和结构季节变动明显,夏季生物群落结构和功能稳定性高,而秋季和冬季生物群落结构和功能稳定性差,主要是由于捕捞强度季节差异(夏季捕捞强度低,秋季捕捞强度高)所致。尤其随着秋季捕捞强度的增大,k选择种类将被r选择种类代替。

Seasonal variation of fishery resources in Egong Bay,Shenzhen

Objective]This research clarified the seasonal variation of fishery resources and its reasons in Egong Bay in Shenzhen, to provide reference for the sustainable utilization and management of fishery resources in typical fisheries area of South China Sea coasts. Method]Based on the data of fishery resources collected through trawl surveys in Egong Bay fisheries area, Shenzhen, from August(autumn) and December(winter) of 2012 to March(spring) and May(summer) of 2013, seasonal variation of nekton species composition, stock density, dominant species, size spectra and biodiversity were studied. Result]Results showed that there were 113 species of nekton, belonged to 18 genus, 50 families, 14 orders and 3 classes in this area. The species number was the largest in summer(61 species) and was the minimum in autumn(53 species). In spring and winter, there was 56 species. The stock density and tail stock density of nekton were the minimum in summer(5950.20 kg/km2 and 356.45 individual/km2 respectively), and the percentage of fish were the highest in this season(51.99% and 42.19%, respectively). Seasonal variation of size spectra indicated that fishing intensity was the highest in autumn, and was the lowest in summer. Additionally, the seasonal variation of biodiversity index was obvious, and the variation trend of Margalef richness index(D '), Shannon-Wiener diversity index(H ') and Pielou evenness index(J ') was the same, which was summer>spring>autumn>winter. Conclusion]Therefore, there was clear seasonal variation in the nekton species, biomass and structure in Egong Bay fisheries area in Shenzhen. Community structure and function in su-mmer were more stable than that in autumn and winter, due to the difference of fishing intensity in different seasons(low intensity in summer and high intensity in autumn). Particularly, k selection species is replaced by r selection species with the increase of fishing intensity in autumn.