澜沧江云南吻孔鲃的耳石年轮特征及其年龄鉴定

Otolith characteristics and age determination of Poropuntius huangchuchieni(Tchang,1962) in Lancang River

通过对采自澜沧江支流补远江的云南吻孔钯（Poropuntiushuangchuchieni）微耳石的微结构和年轮特征的观察，探讨了耳石在鉴定热带地区鱼类年龄中的应用。结果表明：在当年个体的微耳石磨片上没有形成明暗交替的环带，但在高倍镜下可观察到清晰的日轮；通过计数日轮的方法判断了云南吻孔纪当年个体的日龄在135～348d，推算云南吻孔钯的繁殖时间为12月到翌年6月，主要集中在每年1-4月；1龄以上个体耳石磨片上形成了明暗交替的环带，在透射光下明带向暗带过渡的区域为年轮；补远江水温和水位的周年变化是年轮形成的主要原因，暗带形成时间为补远江水温最高、水位逐渐升高的季节；亮带形成于水温和水位均较低的季节；通过计数耳石年轮数量，判断雄性年龄组成为1～5龄，雌性年龄组成为1-6龄。

Poropuntius huangchuchieni is an endemic fish and an important component ot local fisheries in Lancang River. In this study, samplings collected from Buyuan River, a tributary of Lancang River, were aged using a suite of calcified structures including scales, dorsal fin and otoliths. The patterns of sectioned otoliths can be divided into two types： some otoliths recorded as interpretable annuli could be recognized; in other cases, no pattern of alternating zones of opaque and translucent bands, but the daily increment on otoliths can be used to age these fi shes. According to the microincrements of sectioned otolith of currentyear individuals, the age of these fishes were 135 to 348 days, and the birthday of P. huangchuchieni was December to une, mainly in JanuaryApril. Marginal increment analysis of sectioned otoliths showed that the annuli were formed between April and June each year. The formation of annuli was related with the wa ter temperature and the water level. The opaque band formed between April and June, which was corresponding to the highest temperature and the relatively high water level. The translucent bands formed in seasons with lower water temperature and lower water level. The ages of all sam plings ranged from age 1 to 6 for females and age 1 to 5 for males.