Abstract:

ridentiger trigonocephalus〖WTBZ〗,a smallsized fish species widely distributed in the Yangtze estuary,feeds on benthic organisms;contrarily it is preyed by largesized carnivorous fishes.Thus,it plays an important role in the food chain of the Yangtze estuarine ecosystem.Early life stages of many fish species are sensitive to heavy metal pollution.As industrial development,heavy metal pollution has become a problem in the Yangtze estuarine area.However,the studies of toxicology of heavy metal ions to the early life of 〖WTBX〗T.trigonocephalus〖WTBZ〗 are scarce.In this study,the effects of Cu2+,Zn2+and Pb2+ on four early developmental periods,i.e.,fertilized egg to hatching stage,organogenesis stage to hatching stage,eyed stage to hatching stage and larval stage of 〖WTBX〗T.trigonocephalus〖WTBZ〗 were investigated.Experimental results showed that the intensity of toxic effects of 3 heavy metal ions was Cu2+>Zn2+>Pb2+.Toxic symptom of embryo was body curvature,body atrophy,body deformity and pericardial tumefaction.At the beginning of toxicosis larvae moved acutely,and then gradually became weak.The head and body of some experimental larvae appeared curving.The safety concentration of Cu2+,Zn2+ and Pb2+ to the early larvae was 0010 mg/L,0136 mg/L and 0167 mg/L,respectively.The purpose of this study is to provide information that may help to evaluate pollution effects on early life stages of fishes,and to provide guidance for the conservation of important fish species in the Yangtze estuary.
 

Key words: Tridentiger trigonocephalus/heavy metal pollution/toxicity,embryo/early larvae