东海舵鲣的早期发育和生殖习性

ON THE EARLY DEVELOPMENT AND THE REPRODUCTIVE BEHAVIOUR OF AUXIS IN DONG HAI,CHINA

根据主要外部形态,如尾柄上色素的分布和身体各部位的比例值,我们鉴定在东海区的舵鲣属(Auxis Cuvier 1829)鱼类的仔稚鱼有扁舵鲣(Auxis thazard)圆舵鲣(Auxis tapeinoso-ma)和一种目前还未定到种,暂定为舵鲣(Auxis sp.)三种。根据其性腺成熟度及仔稚鱼出现的时间来推断,在东海的产卵期为3—9月,盛期为7、8月。较南海区的产卵期迟一些。产卵范围在北纬 25°30′-32°00′,东经125°以西海区。舵鲣鱼类仔稚鱼在东海的分布面很广,但多靠近陆岸和岛屿附近,一般分布在东经125°以西海区,水深一般为60—100米。栖息海区水温一般为27—29℃盐度为38,00—34,00‰。仔鱼分布与台湾暖流和长江冲淡水有夫,一般在长江冲淡水水舌边缘或台湾暖流和冲淡水的交汇区。台湾暖流向北移动,仔鱼的分布区也相应北移。7月以前分布在北纬28°以南,月份分布在北纬28°以北。

1. 423 postlarvae and juveniles of Auxis Curvier, with body length 3.12--17.5mm, were collected in the Dong Hai, China, during the years of 1971-1980. 2. The specimens were identified as Auxis thazard, Auxis tapeinosoma and Auxissp. and the main characteristics for identification are the pigment distribution on thecaudal peduncle and the ratio of different parts of the body. 3. The spawning season and ground of Auxis in Dong Hai is little Known.According to observation and estimation, the spawning season may possibly be inMarch to september, chiefly in July and August. The area of distribution is mainlyto the south of 28°N and the west of 125°E during March to July and to the north of28°N during August and September. 4. The spawning migration of Auxis is closely related to the Kuroshio WarmCurrent and also under the influence of fresh waters from Chang Jiang river as well.They spawn and move north with the prevalence of Kuroshio at the temperature of27-29℃, salinity of 33-34‰ and in the depth of 60-100 metres.