印度洋中西部黄鳍金枪鱼生物学特性的初步研究

根据2003~2004年1~6月我国农业部印度洋金枪鱼延绳钓观察员项目所收集的有关数据,对印度洋中西部黄鳍金枪鱼的基本生物学特征进行了研究。结果表明,2003年和2004年渔获物中黄鳍金枪鱼加工后体重范围分别为7~81kg和20~78kg,优势组分别为20~50kg和30~60kg。叉长范围分别为70~180 cm和110~170 cm。2003年渔获物雌雄性比的平均值为0.71,月间性比组成差异较小;而2004年渔获雌雄性比的平均值为1.00,月间性比组成差异较大。2003年各月的摄食等级以1~2级为主,月间差异较小;而2004年摄食等级以1级为主,并且月间各等级组成差异大。体长与体重关系为W=2.1890×10-5L2.9269。

Preliminary study on the fishery biology of yellowfin tuna,Thunnus albacares, in the western central Indian Ocean

Based on the data of yellowfin tuna Thunnus albacares caught by tuna longline survey sponsored by Agriculture Department's Fishery Observer Programme in the western central Indian Ocean from January to June in 2003 and 2004,the basic biological characteristics of yellowfin tuna were studied.The results indicated that the dressed weight of yellowfin tuna varied between 7 and 81 kg in 2003 and 20 and 78 kg in 2004,respectively,and the dominant dressed weight varied between 20 and 50kg in 2003 and 30 and 60kg in 2004,respectively.The fork length of yellowfin tuna varied between 70 and 180 cm in 2003 and 110 and(170 cm) in 2004 respectively.Mean sex ratio remained 0.71 and 1.00 in all months of 2003 and 2004 respectively.There was no significant difference for monthly sex ratio in 2003.However,the monthly ratio varied remarkably during 2004.The monthly feeding fullness was dominated by grade 1 and grade 2 in 2003,but there was no significant difference between months.The monthly feeding grade for 2004 was dominated by grade 1 with significant differences between months.The relationship between dressed weight and fork length of yellowfin tuna was W=2.1890×10~(-5)L~(2.9269)