长江中游黄石江段鱼类早期资源现状

为了解长江中游黄石江段鱼类早期资源现状,2015和2016年在黄石江段开展鱼类早期资源调查。共采集鱼类34种,分属6目9科。卵苗组成以贝氏(Hemiculter bleekeri)(占卵苗总捕捞量的85. 7%)、鳊(Parabramis pekinensis)(占10. 9%)和鲢(Hypophthalmichthys molitrix)(占0. 8%)为主。各类群鱼类的仔鱼数量呈现出不同的时间动态。贝氏和鳊在每个月份均占较大比例;鲢在5月份比例较低,之后逐渐升高;银飘鱼(Pseudolaubuca sinensis)和吻虾虎鱼属(Rhinogobius sp)在5、6月份数量较多。2015年估算通过黄石江段的鱼卵、仔鱼径流量分别为6. 7×108粒、1 655. 3×108尾; 2016年分别为19. 0×108粒、1 620. 1×108尾。研究表明,黄石江段是鱼类早期资源的重要分布区,其鱼类早期资源近年来未出现明显的衰退现象。应加强对黄石江段鱼类早期资源的研究和保护。

Status of the Early Stage Fish Resources at Huangshi Section in the Middle Reaches of the Yangtze River

In order to study the early stage fish resources, surveys were carried out at Huangshi section in the middle reaches of the Yangtze River in between 2015 and 2016. There were 34 fish species belonging to 9 families and 6 orders. The most abundant of eggs and larvae were Hemiculter bleekeri (85.7% of the total numbers), Parabramis pekinensis (10.9%) and Hypophthalmichthys molitrix (0.8%). The amount of the larvae of different species displayed different temporal dynamics. Hemiculter bleekeri and Parabramis pekinensis dominated during the whole investigation. The proportion of Hypophthalmichthys molitrix increased after May. The amount of Pseudolaubuca sinensis and Rhinogobius sp reached a peak in May and June. An estimated 165.5 billion larvae and 0.67 billion eggs drifted through the Huangshi section in 2015, while 162.0 billion larvae and 1.90 billion eggs were observed in 2016. It indicated that Huangshi section was an important distribution area for early stage fish resources and there was no obvious decline phenomenon for its resources. More attention should be paid to protecting the early stage fish resources of Huangshi section.