Spatial and temporal patterns of species composition and distribution of shrimp community in the Gonghu Bay, Lake Taihu

Abstract

分别于2005年4月、7月、10月利用蹦网对贡湖湾虾类种类组成和时空分布进行调查.共采集到虾类9605尾, 属于2科3属5种, 分别是秀丽白虾(Exopalaemon modestus)、日本沼虾(Macrobrachium nipponense)、锯齿新米虾中华亚种(Neocaridina denticulata sinensis)、细足米虾(Caridina nilotica gracilipes)、细螯沼虾(Macrobrachium superbum).其中, 秀丽白虾的数量占总数量的63.79%、细足米虾占13.93%, 锯齿新米虾中华亚种占12.69%, 日本沼虾占9.46%, 细螯沼虾占0.11%.虾类密度分布随生境类型和季节不同而有差异, 不同生境中虾类密度分布由大到小顺序是:微齿眼子菜区、混合植被区、马来眼子菜区、沿岸少草区及裸地区, 生物量分布的大小顺序是:微齿眼子菜区、马来眼子菜区、混合植被区、沿岸少草区及裸地区.季节分布中, 虾类密度和生物量分布最大的均为夏季(7月), 其次为春季(4月)和秋季(10月)。;The species composition, spatial and temporal distribution of shrimps in the Gonghu Bay (Lake Taihu) were investiga-ted by sampling with pop-net in April, July and October of 2005.The total of 9605 individuals belonging to 5 species, 3 genera and 2 families were collected.The relative percentage of Exopalaemon modestus, Caridina nilotica gracilipes, Neocaridina denticulata sinensis, Macrobrachium nipponense to the tota1 is 63.79%, 13.93%, 12.69% and 9.46%, respectively.Based on the type and coverage of aquatic vegetation, the lake was categorized into 5 habitat types:Potamogeton maackianus habitat, mixed sub-merged macrophyte habitat, Potamogeton malaianus habitat, littoral zone with a little macrophyte habitat, and naked habitat.The density sequence of all shrimps from high to low is Potamogeton maackianus habitat, mixed submerged macrophyte habitat, Potamogeton malaianus habitat, littoral zone with a little macrophyte habitat and naked habitat.The biomass of shrimps decreased substantially in Potamogeton maackianus habitat, Potamogeton malaianus habitat, combined submerged macrophyte habitat, littoral zone with a little macrophyte habitat, and naked habitat.Each of the dominant species preferred the Potamogeton maackianus habi-tat.In terms of seasonal variation, both the largest density and biomass of the dominant shrimps were in summer (July), followed by spring (April) and autumn (October).