漓江中游16种常见鱼仔稚鱼形态特征初步研究

Morphological Characters of 16 Larval and Juvenile Fish Species in the Middle Reaches of Lijiang River

从漓江中游近岸水域采集的仔稚鱼样品中收集有代表性的仔稚鱼标本,对其形态特征及生态习性进行描述,以补充淡水鱼类早期发育资料。2014年5月至2015年2月,在漓江中游(桂林市至阳朔县段)干流及其支流近岸水域选取13处采样点,用抄网直接捞取法进行逐月采样。采集到8 254尾仔稚鱼样本,依据形态特征鉴定为16种,隶属于3目6科15属,多为外源营养期仔鱼和稚鱼且大部分为小型鱼类,优势种为高体鳑鲏、宽鳍鱲、歺又鱼、食蚊鱼。观察描述了16种鱼仔、稚鱼时期发育特征。比较宽鳍鱲与歺又鱼表明,卵黄吸尽时,宽鳍鱲肌节37对,歺又鱼肌节44(29+13)对;吻至肛门与肛门至尾鳍的长度比约为5∶1,宽鳍鱲肛门约在全长中间。比较高体鳑鲏与广西鱊表明,高体鳑鲏背鳍前部明显的黑色素斑一直持续到稚鱼时期,而广西鱊体表色素较少;高体鳑鲏稚鱼时期的体长为体高的3.5~3.8倍,而广西鱊为4.5~5.0倍。比较子陵吻虾虎鱼与溪吻虾虎鱼表明,子陵吻虾虎鱼体色较浅,溪吻虾虎鱼体色深且分布广泛,鳃盖骨下缘有红色斑点。

Lijiang River, located in northeast Guangxi Province, is a typical mountain river with a complex habitat that supports nearly 100 fish species and it flows through an abundance of land use types. The literature shows that fish diversity in Lijiang River has been declining over the past 30 years. In this study, we characterized the mor- phological characteristics and ecological habits of 16 representative larval and juvenile fish species in the middle Li- jiang River and its tributaries. The study provides information on the early developmental stages of fish in Lijiang River and advances fishery ecology in the Lijiang River basin. A total, of 8 254 larval and juvenile fish were collect- ed from the middle reaches and tributaries of Lijiang River from May 2014 to February 2015. Determination of de- velopmental stage and species show that the fish were mostly larvae in the exogenous feeding period and juveniles of smaller sized species. The fish, identified by morphological characteristics, included 16 species representing 15 genera, 6 families and 3 orders and the dominant species were Rhodeus ocellatus （ Y = 0. 494） , Gambusia affinis （ Y = 0. 039）, Zacco platypus （ Y = 0. 215 ） and Hemiculter leucisculus （ Y = 0. 129 ）. The sixteen common species were scrutinized and their morphological characteristics described, including the morphological differences among similar species （ Z. platypus and H. leucisculus , R. ocellatus and Acheilognathus meridianus , Rhinogobius giurinus and Rhinogobius duospilus）. The comparative study found ： （ 1 ） The sarcomere number of Z. platypus is 37 after the yolk is completely absorbed and the sarcomere number of 1t. leucisculus is 44 （29 ± 13 ）. （2） The distance be- tween snout and anus of H. leucisculus is five times the distance between anus and tailfin, while the anus of Z. platypus is in the middle of the body. （3） The dark spot at the front of the dorsal fin of R. ocellatus in the larval stage persists through the juvenile stage and the pigmentation is less pronounced in A. meridianus. （4） The ratio of length to height for R. ocellatus juveniles is 3.5 - 3.8 ： 1 and 4.5 - 5.0 ： 1 for A. meridianus. （5） The skin pig- mentation of R. giurinus is light and the pigmentation in R. duospilus is dark and extensively distributed. （6） R. duospilus has a red spot on the lower edge of the operculum. To date in China, research on the early developmental stages of freshwater fish is inadequate and we urge continued research on identification of fish species in early life stages that combines the use of morphological characteristic and molecular markers.