[Objective] The aim was to discuss the morphological differences of four carp populations.[Method] Based on traditional morphological data（including countable and measurable characters） and framework data,the morphological differences and phylogenesis of Yellow River carp population（YR）,wild four-naris carp population（WF）,farmed four-naris carp population（FF） and carp population from Suzhou section of Wusong River（WR） were studied by means of multivariate analysis.[Result] There was no significant difference（P〉0.05） in countable characters among four carp populations.Discriminant analysis showed the discriminating accuracy of YR,WF,FF and WR population were 87.5%,78.1%,73.5% and 96.8% respectively,and the synthetic discriminating accuracy of four populations was up to 83.7%.In addition,cluster analysis revealed that YR population and WF population clustered together,while FF population and WR population clustered together.Principal component analysis indicated that the morphological differences among four populations mainly came from the head,tail and vertical axis of fish.[Conclusion] The study could provide theoretical foundations for the purification and rejuvenation of rare four-naris carp.

An ecotoxicological feasibility study was conducted to investigate the effects of ammonia-N(NH4Cl)(0 mg/L 、50 mg/L、150 mg/L、250 mg/L) stress on the activities of GST in livers of wild four-naris carp population and farmed four-naris carp population to ammonia-N exposure in fresh water for 15 days.The results showed that:under the same ammonia concentrations and the same stress time,the change trends of activity of GST enzyme of the wild four-naris carp population was similar to the farm four-naris carp population.The activity of GST enzymes of the wild population was higher than the farm population markedly,except for 250 mg/L groups in the 5 d and 10 d.Under the high concentration stress of ammonia,the GST activity in the livers of the wild population reached the top level faster than the farm population,it suggested that the wild four-naris carp population has a stronger resistance to ammonia stress.

The muscle nutrition composition of 10 wild carps and 10 cultured Cyprinus carpio in Weishan Lake in Jiangsu Province were analyzed.The results showed that the contents of crude protein(18.05%)and calcium(0.69 mg/g)of wild fish were higher than those of cultured fish.The levels of crude fatty acid of wild fish(1.02%)were lower than cultured ones(1.86%),the contents of water content,crude ash and phosphorus were not significantly different between wild and farmed carps.The composition of amino acids of wild and cultured carp was basically the same,containing 18 amino acids.Total contents of 4 flavor amino acids of wild and cultured carps were 6.71% and 6.08 %(fresh sample)respectively.The essential amino acid indexes(EAAI)were 73.35 and 67.44 respectively,and their composition ratio accorded with the standards of FAO/WHO.