热带中西太平洋海域黄鳍金枪鱼的摄食生物学特性

Feeding biology of yellowfin tuna(Thunnus albacares) in tropical central and western Pacific Ocean

利用延绳钓作业方式,于2018年5月—2019年2月对热带中西太平洋海域(163°14’E—173°35’E, 2°03’S—11°17’S)的黄鳍金枪鱼(Thunnus albacares)进行了取样。对取样的919尾黄鳍金枪鱼叉长进行了组成和性比分析,对其中的551尾进行了摄食生物学研究,并使用方差分析(ANOVA)和广义线性混合模型(GLMM)分析了个体叉长、渔获水深、月相等因素对摄食的影响。结果表明:1)样本叉长范围介于87~163 cm,雌雄性比为1∶1.32;2)空胃率占33.76%,在胃含物中,沙丁鱼属、鱿鱼和杂鱼出现频率较高,依次为52.60%、35.34%和33.70%;3)方差分析表明,叉长和月相对Shannon-Weiner多样性指数(H’)和Pielou均匀度指数(J’)具有显著影响,而月份及水深对H’和J’的影响不显著;4)取样个体的摄食等级以0—2级为主,空胃率随着叉长的增加而增大,高摄食强度(2—4级)占比随水深的增加而增大;5)广义线性混合模型(GLMM)拟合结果显示,生物因素(叉长和性别)、时空因素(月相的余弦和水深)对黄鳍金枪鱼的摄食强度均有显著影响。

We had collected 919 individuals of yellowfin tuna(Thunnus albacares) in the tropical central and western Pacific Ocean(163°14’E-173°35’E, 2°03’S-11°17’S) from May 2018 to February 2019 by pelagic longline fishing trageting tunas to analyze their size frequency and sex ratio. The feeding biology of 551 individulas was also studied. The effects of fork length, fishing water depth and lunar phase on feeding biology were analyzed by analysis of variance(ANOVA) and generalized linear mixed model(GLMM). The results show that: 1) The fork length range was 87-163 cm, and the sex ratio(female to male) was 1: 1.32.2) The hollow stomach rate accounted for 33.76%. For tunas with non-empty stomach, the frequency of presense of sardines,squid and miscellaneous fish in stomach contents were 52.60%, 35.34% and 33.70%, respectively. 3) The ANOVA results show that fork length and lunar phase had significant effects on the Shannon-Weiner diversity index(H’) and Pielou evenness index(J’), while month and water depth did not. 4) The feeding intensity was mainly at Level 0-2, and the empty stomach rate increased as the fork length increased. The proportion of high feeding intensity(Level 2-4) increased gradually as water depth increased. 5) The result of GLMM fit shows that biological factors(fork length and gender), spatial and temporal factors(cosine of lunar phase and water depth) had significant effects on the feeding intensity of yellowfin tuna.