奉贤近海仔鱼的分布及其与水环境的关系

Distribution of larvae fish and its relationships with water environmental factors in offshore area of Fengxian

根据2006年5月和8月在奉贤附近海域(30°32.40′N—30°49.8′N;121°25.2′E—121°54′E)进行的渔业资源、生态调查资料,对该水域仔稚鱼的种类组成、数量分布的季节变化及其与水环境的关系作了分析。结果表明:鲈形目和鲱形目出现的种类最多;春季种类组成复杂,结构相对夏季要稳定,种间分布较均匀;夏季优势种较春季突出,优势度较大,数量较多,平面分布呈现由内侧向外侧的递减趋势;长江径流与外海水在外侧水域的南汇嘴处形成咸淡水交汇水域,环境稳定性较差,加之海域处于强潮流区,水沙运移频繁,对仔鱼平面分布产生影响;此海域沿岸地处化工区,水体污染严重,仔鱼的数量和种群减少。

Based on the investigation of fishery resources and ecology in offshore area of Fengxian in May and August of 2006, the seasonal changes of larvae fish species composition and quantity distribution, and their relationships with hydrological conditions were discussed. The results showed that Peiciformes and Clupeiformes had more species than other orders. Comparing with those in summer, the species composition in spring was more complicated, species quantity was more, and interspecies＇distribution was more uniform. The dominance value of dominant species in summer was higher than that in spring. The larvae biomass was also higher in summer, which was more inboard than outboard. The Changjiang River and the open sea waters joined at the Nanhui mouth of the outboard area, and the environment was unstable. Tidal flow and sediment transportation affected the larvae＇ s horizontal distribution, and the polluted waters from chemical factories along the shore made the larvae＇ s biomass and population dropped day by day.