大源湖虾类种类组成、时空分布及生物量估算

利用“蹦网”(pop-net)采样,调查了龙感湖一个湖汊—大源湖的虾类种类组成、空间分布,估算优势种类的生物量.在2002年冬季的31个采样点和2003年春季42个采样点中共采集到虾类2707尾,属于甲壳纲,十足目的2科5属.秀丽白虾(Exopalaemon modestus Heller)是大源湖虾类的优势种,占采样总数量的84.1%.根据水深分布特征和水生植被的分布格局,划分生境类型,苦草生境是各虾类分布最多的生境,冬季优势种秀丽白虾在苦草生境中的密度是8.14 ind/m2,生物量是1.59 g/m2.春季分别是2.98 ind/m2,1.04 g/m2.春季水深对虾类的分布影响较小,冬季虾类主要分布在深水区.表明水生植被是影响虾类分布的主要环境因子;在冬季,水深成为影响虾类分布的主要环境因子之一.

Species Composition,Spatio-temporal Distribution and Biomass of Shrimps in the Dayuan Lake

The species composition,spatio-temporal distribution and biomass estimation of shrimps in the Dayuan Lake,Huangmei county,Hubei province,are investigated by sampling with pop-net in the winter of 2002 and spring of 2003.The total of 2707 individuals belong to 5 species,5 genera and 2 families.The dominant species is exopalaemon modestus,which contributes 84.1% to the total.According to water depth and the type and cover of vegetation,three habitat types are classified: Vallisnerria spiralis habitat,Myriophyllum spicatum habitat and naked habitat,respectively.In the winter of 2002,the dominant shrimp species prefer the Vallisnerria spiralis habitat.In the Vallisnerria spiralis habitat,the dominant species has the highest density(8.14 ind/m2).The biomass is 1.59 g/m2.Also the shrimps prefer the Deep water area.In the spring of 2003,the dominant species has the highest density(2.98 ind/m2).The biomass is 1.04 g/m2 in the Vallisnerria spiralis habitat.While the water depth is not a dominant effect factor to the shrimps' distribution.The distribution of aquatic vegetation is the dominant environment factor that affectes the distribution of shrimps.In winter,the water depth is also a dominant effect factor to the shrimps' distribution.