天津海域春夏季鱼卵、仔稚鱼的种类组成与数量分布

Species composition and abundance of fish eggs,larvae,and juveniles in Tianjin sea area during spring and summer

于2008年5—8月对天津海域的鱼卵、仔稚鱼进行了4个航次的调查,共采集到鱼卵26 654粒,仔稚鱼20 534尾,隶属于7目12科25种。鱼卵和仔稚鱼的平均密度分别为1.70、1.18 ind./m3;5月份鱼卵和仔稚鱼最多,6月份次之,8月份最少;与历史资料比较,5月份仍是天津海域鱼类的产卵高峰期,但5月份鱼卵和仔稚鱼所占比例有所下降;南部中心产卵场位置变化不大,北部中心产卵场向北移动。本研究结果表明,近年来天津海域鱼卵、仔稚鱼的种类和数量呈减少趋势,产卵场出现退化现象。

The species composition and abundance of fish eggs, larvae, and juveniles was surveyed monthly in Tianjin sea area during spring and summer from May to August in 2008. Total of 26 654 eggs and 20 534 larvae and juveniles were collected and identified to be 25 species, 12 families and 7 orders during the four cruises. The eggs had an average density of 1.70 ind./m3 and the larvae and the juveniles 1.18 ind./m3, with the maximal abun- dance in May, followed by in June and the minimal abundance in August. Compared with the previous data, the spawning peak was still observed in May, but the abundance and proportion of fish eggs, larvae, and juveniles were found to be decreased in May. There was no significant change in the south center spawning ground, but the North center spawning ground was found to be moved northwards. The findings revealed that the species number and a- bundance of fish eggs, larvae, and juveniles were shown to be decreased, and the spawning ground shows degrada- tion in Tianjin sea area in recent years.