鲢♀×鳙♂杂交鱼与其亲本的形态差异分析OA北大核心CSTPCD

Silver carp(Hypophthalmichthys molitrix)and bighead carp(Hypophthalmichthys nobilis)are endemic to China,with few natural hybrids found within their native distribution ranges.However,a significant number of natural hybrids emerged when these two species colonized the Mississippi River in the United States of America.To comprehend the morphological differences and biological characteristics of hybrid fish resulting from silver carp and bighead carp,comparative observations were conducted on external morphological traits,body coloration,pigment cells,and morphological changes in some organs and bones among silver carp,bighead carp,and their hybrid(silver carp ♀× bighead carp ♂).The results indicated extremely significant differences(P＜0.05)in six traits out of 18 countable traits between the hybrids and their parents,with an average hybrid index of 72.2,indicating a slight bias towards paternal bighead carp.Utilizing 39 quantifiable and truss traits,principal component analysis,discriminant analysis,and cluster analysis revealed evident differences among the hybrids,silver carp,and bighead carp,although the hybrids exhibited closer proximity to maternal silver carp.Morphological disparities among the hybrids mainly centered on the head and trunk anterior to the dorsal fin.Body surface and peritoneum colors of the hybrids were intermediate between those of silver carp and bighead carp,leaning closer to silver carp.Nonetheless,the number of melanocytes in the scales was significantly higher in hybrids than in silver carp(P＜0.05).Moreover,gill rake characteristics of the hybrids resembled those of bighead carp but noticeably differed from those of silver carp.The shape and size of posterior swim bladders in hybrids differed from those of silver carp and bighead carp.While most skeletal characteristics of hybrids resembled those of silver carp,hybrid skeletal size ranged between that of silver carp and bighead carp,offering a scientific foundation for understanding the biological traits of hybrid offspring from silver carp and bighead carp,their ecological adaptability in migration areas,and the germplasm protection of both species in China.