扁担塘虾类群落组成、空间分布和生物量估算

2002年秋季,利用“蹦网”(Popnet)采样,调查了扁担塘的虾类组成、空间分布和生物量,以期为虾类资源的合理开发利用提供科学依据。采集样点31个,共采集到虾类44287尾,由6种组成,其中长臂虾科4种,匙指虾科2种。优势种是细足米虾(CaridinaniloticgracilipesdeMan)、日本沼虾(MacrobrachiumnipponensedeHaan)和中华新米虾(NeocaridinadenticulatesinensisKubo),它们占采样总数量的99.3%。根据水深特征将扁担塘划分为浅水区(1.5m);根据水生植被的分布格局将全湖划分四种生境类型:苦草生境、聚草生境、金鱼藻生境和裸地生境。协方差分析的结果表明:水深类型对虾类的分布没有显著影响,生境类型是决定虾类密度分布的主要因素。整个湖区虾类密度为83.36ind/m2,生物量为3.97g/m2。其中细足米虾的密度和生物量分别为64.69ind/m2,1.53g/m2;日本沼虾为8.99ind/m2,2.09g/m2;中华新米虾为8.61ind/m2,0.22g/m2。  

SPECIES COMPOSITION, SPATIAL DISTRIBUTION AND BIOMASS OF SHRIMP COMMUNITY IN THE BIANDANTANG LAKE

The species composition,spatial distribution and biomass of shrimps in the Biandantang Lake,Hubei province,were in-vestigated by sampling with pop-net (10m2) in the Autumn of 2002. The total of 44 287 individuals belonging to 6 species,5 gen-era and 2 families,were collected from the 31 sampling sites. The dominant species were Macrobrachium nipponense, Caridinanilotic gracilipes and Neocaridina denticulate sinensis,which contributed 99. 3 %to the total. In terms of water depth,the lake wasclassified into 3 water-depth areas: shallow area ( 1. 5m). Based onthe type and coverof aquaticvegetation,the lake was categorized into 4 habitat types: Vallisnerria spiralis habitat, Ceratophyllumdemersum habitat, Myriophyllum spicatum habitat,and naked habitat. For dominant shrimps,significant difference in density wasnot observed among 3 water-depth areas (ANCOV,P >0. 05) ; whereas,it was found among 4 habitat types (ANCOV, P 2and 3. 97 g/m2,respectively,of which C.nilotic gracilipes contributed 64. 69 ind/m2and1. 53 g/m2, M. nipponense 8. 99 ind/m2and 2. 09 g/m2,and N. denticulate sinensis 8. 61 ind/m2and 0. 22 g/m2.