白令海阿留申海盆区狭鳕当年生幼鱼数量分布的调查研究

DISTRIBUTION AND ABUNDANCE OF AGE ZERO WALLEYE POLLOCK THERAGRA CHALCOGRAMMA IN THE ALEUEIAN BASIN

１９９３年夏季白令海狭鳕资源调查期间，作者等应用声学／拖网评估调查方法，首次发现阿留申海盆区有大量当年生狭鳕幼鱼分布。研究结果表明：（１）当年生幼鱼主要分布在海盆区东北部，密集区位于东白令海陆架斜坡与公海区之间，呈西北东南走向；（２）鱼群主要栖息于中上层８０—１２０米处，有明显的昼夜垂直移动现象；（３）７月份海盆区东北部幼鱼鱼体长度为２９—４７毫米，而南部波哥斯洛夫岛附近的鱼体长度仅为１１—１７毫米，系两个不同产卵期鱼群的子代；（４）幼鱼主要栖息层的水温为３—５℃，盐度为３２．９—３３．１，其分布与陆架斜坡地理环境和饵料生物关系较密切。

During a survey of Bering Sea pollock resources from June to August,1993,a large concentration of age zero pollock was discovered in the Aleutian Basin by using echointegration/midwater trawl survey method. The study result indicates that :1)The juvenilewere mainly distributed in the northeast part of the Aleutia n Basin extending fromnorihwest to southeast,and the densest distribution area was observed between the easterncontinental slope and the Bering High Seas;2)The juveniles mainly inhabited the waterlayer of 80 120 m depth,and showed a clear vertical migration;3)During July,thejuveniles in the northeast part of the Aleutian Basin ranged from 29 47 mm in fork length,but the juvenile around the Bogslof Island ranged from only 11 17 mm in fork length,which may be indicative of juveniles of two separate stocks spawning at different times;4)The temperature and salinity of the water inhabited by juvenile were 3 5 ℃ and about 33,respectively, There seems to be a good relationship between the concentration of age zeropollock and geographic environment in the continental slope and forage organisms.