入侵种麦穗鱼的形态特征分析

研究不同生境条件下入侵种的形态差异是了解生物入侵的重要手段。运用多变量形态度量学和框架结构形态学方法,测量了采自四川南充、石棉、茂县和西昌共4个不同栖息地的94尾麦穗鱼(Pseudorasbora parva)标本,在双筒解剖镜下检视,采用电子数显游标卡尺测量了侧线鳞、侧线上鳞、侧线下鳞以及背鳍、胸鳍、腹鳍、臀鳍的分枝鳍条共7个可数性状。应用多变量形态度量学方法,选择18个框架结构性状和16个常规性状进行主成分分析。结果表明,3个主成分的累计贡献率达到76.59%,4个不同地点的标本聚在一起没有分开,表明入侵种麦穗鱼各居群间的形态没有显著差异。结合文献资料分析了麦穗鱼入侵的原因,指出了在进行经济鱼类引种过程中,应针对麦穗鱼制定有效地管理措施,实行早期的监测和预警系统,防止麦穗鱼的卵、苗种和幼鱼等人为侵入;已发现的麦穗鱼应该及时处理,避免其在引入地进一步扩散;对于已经在引入地建立了自然种群的麦穗鱼,应该根据生物学原理(如生理、生态因子的耐受性、食性、繁殖特性、寄生虫感染等)进行综合治理,使其对土著鱼类的危害处在可控范围之内。

Morphometrics Analysis of the Invasive Pseudorasbora parva from Different Habitats

It is an important means to understand the ecology of biological invasions by studying the morphometric variations among different habitats.The Pseudorasbora parva is a small cyprinid species originating from Yangtze River and many countries and regions have been invaded by this species in less than 50 years.By the binocular microscope,we observed ninety-four specimens of P.parva from four different localities(Nanchong,Shimian,Maoxian and Xichang).All these 7 countable traits(sucha as lateral line scales,upper lateral-line scales,upper lateral-line scales,dorsal fin,pectoral fin,pelvic fin and anal fin) were measured by digital vernier caliper.Eighteen frames and sixteen general characteristics,thirty-four characteristics in sum were measured for multivariate morphometrics analysis.Based on the results of principal components analysis,specimens clustered together by scatter plots of scores could not be divided.This results indicated that there were no significant morphological differences among invasive P.parva from these four sites.Integrated with literature records,the threatening factors on the endemic fish diversity have been analyzed.In order to prevent the P.parva invasion,there are needs(i) to construct an early warning system with the aim of reducing the possibly of invasive P.parva accidental introduction;(ii) to eradicate the initial introduction prior to natural spread into open systems rapidly;(iii) to apply biological control methods monitoring the harmful influence of invasive species on the endemic fish,for example,parasites and pathogens infection,temperature limits,etc.