梨形环棱螺的食性及其在生态沟渠中的净水作用

摘要

The purification systems of ecological ditch are increasingly used for ex situ biorestoration of water quality in extensively cultured fish ponds.Gastropods are an important constructional element of the water purification systems.In order to examine the function of Bellamya purificata in the ecological ditch from the perspective of food chain,we focused on the feeding habits and diet selectivity of this benthic species.Bellamya purificata were collected from a ecological channel in Chonghu Fish Farm of Gong' an County,Hubei province in 2012.A total of 55 gut content samples were obtained and the feeding habits and diet selectivity were analyzed.The results showed that the food item can be approximately divided into four groups,i.e.alga,small invertebrates,debris,and others (including macrophytes and unidentified items).According to descending order of percentage of relative importance index,the food composition ranks as alga,debris,other,and small invertebrates Since removal of the food items can decrease organic loading,it may be feasible to control the organic contents so as to purify water in ecological ditch through reasonable stocking and harvesting of Bellamya purificat.%生态沟渠净水系统越来越多地被用于精养鱼池水质的异位修复,腹足类作为生态沟渠净水系统的构件也备受重视.研究食性和食物选择性可以从食物链角度查明梨形环棱螺(Bellamya purificata)在生态净水系统中的作用.2012年夏季在湖北省荆州市公安县崇湖渔场内一条生态沟渠内采集梨形环棱螺,解剖得到55个肠道内含物样品,对其食性和食物选择性做了初步的分析.结果表明:梨形环棱螺的食物种类主要由藻类、小型无脊椎动物、有机碎屑和其它(包括高等水生植物碎片和难以鉴定的成分)4个大的类群组成.食物组成依相对重要性指数百分比高低顺序排列依次为藻类、有机碎屑、其它和小型无脊椎动物.鉴于上述食物成分的清除有利于降低水体的有机负荷,所以可以通过梨形环棱螺的合理放养和收获来控制生态沟渠中的有机物含量,达到净化水质的目的.