东海区北部小黄鱼生殖群体分布及与水团关系

根据2003～2005年每年4月东海区北部小黄鱼CPUE、海水温度和盐度数据,分析了春季小黄鱼分布与水团间关系。结果表明,2003～2005年每年4月小黄鱼的平均CPUE分别为4.72、3.47和1.96 kg/h;小黄鱼的主要分布区可分为4个海域:A,黄海南部近海;B,黄、东海交界海域;C,长江口外海域;D,东海中北部海域;小黄鱼最适生存的底层温度为10～14℃,底层盐度为32～34.3;研究海域内底层水团包括:东海北部底层冷水团、黄海水团、黄-东海混合水团以及东海混合水团;分布区C内的小黄鱼主要位于东海混合水团和黄-东海混合水团的交汇处,其它3个分布区内的小黄鱼都是在东海北部底层冷水团与其它水团的交汇处。

Relationship between Redlip Croaker (Larimichthys polyactis)Spawning Stock Distribution and Water Masses Dynamics in Northern East China Sea Region

Redlip croaker(Larimichthys polyactis) is the important ocean economic fish in China,which is distributed extensively in East China Sea,Yellow Sea and Bohai Sea,particularly in northern East China Sea region.The distribution of L.polyactis may be affected by water masses.Relationships between L.polyactis spawning stock distribution and water masses dynamics in northern East China Sea region were analyzed with the data about the CPUE of L.polyactis and seawater temperature and seawater salinity in April of 2003 to 2005.The results show that the average CPUE of L.polyactis was 4.72kg/h,3.47kg/h and 1.96kg/h in April 2003 to 2005,respectively.The main distribution area of L.polyactis in April can be divided into four areas:A,the sea area of the offshore southern Yellow Sea along 32°30′-34°00′N and 123°00′-124°00′E;B,the sea area of the boundary of Yellow Sea and East China Sea along 32°00′-32°30′N and 124°30′-126°00′E;C,the sea area of the outer Yangtze along 30°30′-31°00′N and 123°30′-125°00′E;D,the sea area of the central and northern East China Sea along 30°30′-31°00′N and 125°30′-126°30′E.The optimum sea bottom temperature and salinity for L.polyactis in April were 10-14℃ and 32‰-34.3‰.The water masses in the study area include the Northern East China Sea Bottom Cold Water(EC),Yellow Sea Water Mass(Y),Yellow Sea-East China Sea Mixing Water Mass(YE),and East China Sea Mixing Water Mass(E).The force of EC was the strongest in 2003,while the weakest in 2005.The force of Y was the strongest in 2003,while the weakest in 2004.The force of YE was the strongest in 2005,while the weakest in 2003.The force of E was the strongest in 2004,while the weakest in 2003.The L.polyactis in the area C was mainly distributed in the mixed sea area of E and YE,the other three areas were distributed mainly in the mixed sea areas of EC and other water masses.It is concluded primarily that the spawning stock of L.polyactis in spring is mainly distributed in the boundaries of different water masses,especially in the boundary of EC and other water masses.