南太平洋所罗门群岛海域长鳍金枪鱼的生物学特征

根据2011年8-9月南太平洋所罗门群岛海域长鳍金枪鱼资源调查数据,对捕获的长鳍金枪鱼群体组成、性比、性腺成熟度、摄食等生物学特性进行了分析。结果表明:(1)南太平洋延绳钓渔业捕获的长鳍金枪鱼个体较大,叉长为77.5～112.9 cm,优势叉长为93～103 cm(67.2%),平均叉长97.6 cm,雌性与雄性个体大小存在显著差异(P<0.05);(2)体重(W,kg)与叉长(FL,cm)关系分别为:W=4×10-5FL2.829(9总体),W=10-4FL2.565(9雄性),W=6×10-5FL2.764(7雌性);(3)雌、雄性别比为1:1.94,成熟期雌性个体性以Ⅴ、Ⅵ期为主(94.4%),雄性个体以Ⅲ、Ⅳ期为主(65.7%)。推测南太平洋长鳍金枪鱼在调查海域及调查期间存在产卵行为;(4)长鳍金枪鱼在繁殖期间摄食水平较低,摄食等级以0、1级为主(81.1%),其中空胃率占56.6%。平均饱满度指数较低,且与个体大小无关(P>0.05)。

Preliminary Study of Fishery Biology of Albacore, Thunnus alalunga, in Solomon Islands of the South Pacific Ocean

Based on the surveys by Chinese tuna longline fleets during August to September 2011 in the South Pacific Ocean,the biological features including population structure,sex ratio,developmental stages of gonads,feeding of albacore Thunnus alalunga was analyzed.Results showed:(1) Longline caught albacore were relatively larger,with an average fork length(FL) of 97.6cm and most fish(67.2%) were in the 77.5-112.9 cm size range.The differences in albacore size for both sexes were significant by testing(P<0.05).(2)The length-weight relationship were W=4×10-5FL2.829 9 for both sexes,W=10-4FL2.565 9 for male,and W=6×10-5FL2.764 7 for female,respectively.(3)The sex ratio of albacore was 1:1.94 during the surveys.The gonadal maturity for the females was dominant in stage Ⅴ and stage Ⅵ(94.4%),however,the gonadal maturity for the males was dominant in stageⅢ and stage Ⅳ(65.7%).Occurrence of gonads in late stages of development indicated that the South Pacific albacore spawned in the survey months and areas.(4)The ration level of South Pacific albacore was relatively lower,the stages 0 and 1 were mainly found in the feeding stage(81.1%) and empty stomach individuals account for 56.6%.Mean stomach fullness index was low,and the difference in different size compositions was not obvious(P>0.05).