EVALUATION OF FISHERY ECOLOGICAL ENVIRONMENT IN THE JINGJIANG REACH OF THE YANGTZE RIVER

Jingjiang reach of the Yangtze River is an important spawning site for four major Chinese carps.In order to assess the water quality and the suitability for four major Chinese carps to spawn,investigations focused on this site were carried out from 1997 to 2002.The water from 3 sampling stations were monitored for 17 physico-chemical parameters (temperature,pH,dissolved oxygen,permanganate index, ammonium,total phosphorus,volat ile phenolic,oil,total cyanide,chromium,Cu,Zu,Pb,Cd,Hg and As).Additionally,the species and density of plankton were also measured. They were then evaluated by applying comprehensive assessment method of river water quality,the Kolkwitz &Marsson system.The results were as follows:Water quality was fit for four major Chinese carps to spawn.For it was about grade according to the environmental quality standards for surface water,and only at few sampling sites,the copper or oil in water was higher than the content of the criterion of water quality for fisheries.According to the results of invest igation on the plankton, water in Jingjiang reach of the Yangtze river is polluted to certain extent and is allocated to Bmiddle polluted zone.