普里兹湾邻近海域大磷虾的生殖特点研究

本文依据 1 989/1 990和 1 990 /1 991夏季 ,“极地”号考察船在普里兹湾邻近海域 (南大洋的印度洋区 )的拖网样品 ,对大磷虾的性腺发育和生殖群体的年龄结构等 ,进行了分析研究。大磷虾的生殖开始于 1月 ,一直持续到 3月。高峰期出现在 2月中旬 ,比大西洋区相比迟了一个月。生殖群体主要包括两个年龄组 ,即 3 + 龄和 4+ 龄。换句话说 ,绝大部分个体是三年性成熟 ,一生可生殖两次 ,不排除少数个体两年性成熟 ,或第三次性成熟的可能 ,但比例非常小。在 5 91 6尾能区分性别的个体中 ,雄性个体只占 3 4 .1 %。雄性比随体长的增加而降低。体长大于 5 0 mm的个体中雄性仅占 2 2 .9%。

SEXUAL MATURITY STAGES AND SPAWNING OF ANTARCTIC KRILL(EUPHAUSIA SUPERBA DANA) IN THE PRYDZ BAY REGION

This paper presents the results of net sampling carried out on two marine cruises during the austral summer of 1989/1990 and 1990/1991 in the Prydz Bay region (Indian Ocean sector of the Southern Ocean) by the Chinese R/V "Jidi".The sexual maturity stages of totally 8243 specimens of Antarctic krill(Euphausia superba Dana) were examined. The spawning season begins in January and extends to March with the maximum spawning occurring in mid-or late-February,about one month later compared with the Atlantic sector.The L/F distribution of gravid females (3DF) shows that the spawning popualtion mainly consists of two age groups:3 + and 4 +. The 3 + adults are the main spawners with the 4 + adults partly contributing.2 + and 5 + seems to be very scare in the spawning population if any.Among the 5916 specimens determinable sex only 34.1% are males. The percentage of males decreases with the increasing of body size.It drops to 22.9% when the body length exceeds 50 mm.