珠江口伶仃洋海域底层游泳动物的季节变化

珠江口伶仃洋海域是渔业资源的重要栖息地,近年来由于人类活动的加剧导致生态环境质量下降。为进一步了解栖息环境恶化对渔业资源的影响,于2009年8月至2010年4月采用底拖网在珠江口伶仃洋海域进行了游泳动物4个季节的调查。共鉴定游泳动物92种,其中鱼类54种,甲壳类32种和头足类6种。游泳动物种数夏季最高,为52种,春季最低,仅35种,春、夏季和冬、春季种类季节更替显著。优势种组成较为稳定,以日本蟳(Charybdis japonica)、黑斑口虾蛄(Oratosquilla kempi)和棘头梅童鱼(Collichthys lucidus)为主要优势种,其中日本蟳为全年优势种,平均尾数密度占总密度的8.07%～26.22%。游泳动物资源密度和尾数密度季节变化趋势一致,均为夏季最高,秋季和春季次之,冬季最低。珠江口伶仃洋海域温度和盐度有明显的季节变化,夏季和秋季温度较高,盐度较低,冬季和春季温度较低,而盐度较高。温度是伶仃洋海域游泳动物种类和数量季节变化的主要因子。与历史资料比较,珠江口主要经济鱼、虾类出现小型化趋势。

Seasonal variations of bottom nekton in the Lingding Bay of Pearl River Estuary,China

The Lingding Bay,an important area for fishery resources,has endured the deterioration of ecological environment due to human activities.In order to understand the influence of deteriorative environment on the fisheries,seasonal variations of nekton were studied based on the data from four cruises conducted from August 2009 to April 2010 in the Lingding Bay of Pearl River Estuary.A total of 92 species was identified,including 54 species of fishes,32 crustaceans and 6 cephalopods.The species richness was recorded with a maximum in summer and a minimum in winter.The species number of nekton alternated significantly from spring to summer and from winter to spring.The dominant species were stable,which were Charybdis japonica,Oratosquilla kempi and Collichthys lucidus.Among them,Charybdis japonica dominated during the whole year,with the average density occupying 8.07% 26.22% of the total density.The seasonal variations of stock biomass and density of nekton were in accordance with the temperature,with their highest values in summer and the lowest ones in winter.The variations of temperature and salinity showed a seasonal distribution,with high temperature and low salinity in summer and autumn,low temperature and high salinity in winter and spring.Temperature played an important role in the influence of stock biomass and density of nekton in the Lingding Bay.Comparing with the historical data,we find that main commercial fishes and shrimps have been miniaturized in the Lingding Bay of Pearl River Estuary