太湖湖鲚渔获量变化与生物环境间相互关系

2003-2004年在汉江中游江段共监测654船次，统计渔获物6914．16 kg，生物学测定1682尾鱼，共采集鱼类78 种，隶属18科58属．目前汉江中游渔获物组成和结构与20世纪70年代相比发生了较大变化，翘嘴红鲌、瓦氏黄颡鱼、鲶、 鲢、黄尾鲴、大鳍蠖等在渔获物中比例已经很少；草鱼资源也明显下降；铜鱼、青鱼、蒙古红鲐、鳡、细鳞斜颌鲴、吻鮈 、长吻 鮠、拟尖头红鲌、鳙、鳜等在渔获物中已基本消失；而鲤、鲫、黄颡鱼、长春鳊、赤服鳟等中小型鱼类在渔获物中的比例却相 对上升；渔获物中个体大的鱼减少，低龄鱼及幼鱼个体比重增加．与70年代资料相比，汉江中游鱼类资源已呈衰退趋势．

A Study on the Chaise of Lake Anchovy(Coilia ectenes taihuensis Yen et Lin) Catches and Its Mutual Relationship to the Biological Environment in Lake Talhu

In the years 2003-2004,a survey on the fishery status was taken in the middle reaches of the Hanjiang River.A total of 654 boats were investigated ,6914.16kg fish catch were collected and 1682 tails of fish were measured.Fishes were belonging to 18 families,58 genera and 78 species.In comparison with the relevant data in 1970's,fish catch composition and structure had more change at present time.For example,the ratio and quantity of Culter ilishaeformis (Bleeker),Pelteobagrus vacheUi(Richardson),Si- lurus asotus Linnaeus,Hypophthalmichthys molitrix (Cuvieret Valenciennes) ,Xenocypris davidi Bleeker,Mystus macropterus(Bleek- er) and Ctenopharyngodon idellus (Cuvier et Valenciennes)in fish catch had been greatly decreasing.Some fishes such as Coreius heterodon (Bleeker),Mylopharyngodon piceus (Richardson),Culter mongolicus (Basilewsky),Elopichthys bambusa (Richardson), Xenocypris microlepis Bleeker,Rhinogobio typw Bleeker,Leiocassis longirostris G(?)nther,Erythroculter oxycephaloidaes (Kreuenberg et Pappenhein),Aristichthys nobilis (Richardson),and Siniperca chuatsi(Basilewsky) had disappeared in some degree.However the number of medium and small-sized fish,such as Cyprinus (Cyprians)carpio Linnaeus,Cyprinus carassiua Linnaeus,Pelteobagrus ful- vidraco (Richardson),Parabramis pekinensis (Basilwsky),Squaliobarbus curriculus (Richardson)and so on had been increasing. Amongst fish catch,the number and ratio of low-aged fish and adolescent fish had been increasing,and at the same time big-sized fish decreasing,On the basis of the facts above,there can he concluded that the fishery resources in the middle reaches of the Han- jiang River has been declining.