Fish Community Structure And Species Diversity Of Taiji Section In The Middle Reach Of The Ganjiang River

The Ganjiang river locates at south shore of Yangtze River and originate from Gong shui of Wuyi Mountain and Zhang shui of Da gen ling, is located at Longitude east of Greenwich is116°22', and the Northern latiutde is from25°77'. Fringe by Ganzhou state and Xingan country, Ganjiang river is divided into upstream, midstream and the downstream, among which the upstream length312km, midstream Length303km, downstream Length208km, the main stem of Ganjiang River is Length823km. Drainage area is82809km2.The river's noodles of the Ganjiang river in the Taihe to Jian reach is wide, flowing water rapids, owning to its natural environment, it is abundant in fish resources. In the middle section of Ganjiang River, the wan'an Dam was build up in1993, at present are starting to build Shihutang, Xiajiang and Yongtai water conservancy projec. These water facilities in the middle section of Ganjiang River's fish resources constitute a serious threat, resulting in a very negative impact.In order to study the influence of Shihutang water conservancy project on fish resource, this paper surveys fish resources in the Taiji section of Ganjiang River. Investigation of the main content is resources status of fish resources in the Tai ji section of Ganjiang river's, the influence of Construction period of Shihutang water conservancy project, make a predictive analysis about the influence of completion period of Shihutang water conservancy project. The primary results were showed as follows:(1) Investigated the fish resources about Construction period of Shihutang water conservancy project in Tai ji section of Ganjiang River in July,2010and July,2011, by four seasons.4245specimens, including Sixty-one species, belonging to Forty-six genera, eleven families and four orders, were collected. Cypriniformesis the most species-rich order, account for75.41%of total stream fish.(2) The ecotypeof fish in Taiji section of Ganjiang River:Sedentary is the most species-rich, account for nearly70.00%of ecological groups; Omnivore is the most species-rich, account for nearly61.00%of feeding habits; mid&sub-stratum and Sub-stratum is the most species-rich, account for nearly72.00%of habitat types.(3) The dominant fish species in the Taiji section of Ganjiang River:Hemiculter bleekeri (13.08%), Xenocypris argentea (21.76%), Saurogobio dabryi (11.09%), Squalidus argentatus (35.66%) and Pseudobagrus fulvldraco (13.96%). The respective correlation model of their body weight and body length is:W=43.88L0.314, W=50.193L0.292, W=34.779L0.3546, W=42.915L0.363, W=42.38L0.315.(4) The comparison of species biodiversity had been made among the streams which sampling sites located. The results indicated that:①the fish species of Summer is the highest (S:46), but the lowest is Winter (S:25);②the fish species richness of Summer is the highest (D:5.28), but the lowest is Winter (D:3.30);③the fish species diversity of Spring is the highest (H:2.54), but the lowest is Winter (H:2.09);④the fish species evenness of Spring is the highest (E:0.71), but the lowest is autumn (E:0.58);⑤the fish species dominance of Spring is the highest (λ:0.23), but the lowest is autumn (λ:0.12).