浙江南部近海小黄鱼生长和性成熟特征的异质性

Heterogeneity of growth and maturity of Larimichthys polyactis in the offshore waters of southern Zhejiang,China

鱼类生长和性成熟是渔业资源生物学研究的基础内容。为分析小黄鱼的生物学特征,本文以2015年11月—2018年11月浙江南部近海13个渔业资源季度调查航次获得的4920尾小黄鱼样品为研究对象,使用线性混合效应模型(LMEM),研究了小黄鱼生长和性成熟特征的异质性。结果表明:小黄鱼体长范围为13~215 mm,优势体长组为110~154 mm,体重范围为0.5~182.2 g,优势体重组为20~55 g。体长和体重关系方面,加入季节、性别和年份随机效应的LMEM模型AIC值和RMSE值最小,拟合效果最好,季节对小黄鱼体长和体重关系的影响最显著。小黄鱼体长(L)和体重(W)关系为W=4.22×10^(-5)L^(2.79),在体长大于160 mm后,小黄鱼体重增长率春季、夏季最快,冬季次之,秋季最慢,2015年体重增长率最快,其次为2017和2018年,2016年最慢,雄性体重增长率快于雌性。小黄鱼样品中,性腺成熟度为Ⅱ期的未性成熟小黄鱼比重最高,占50.4%,达到性成熟的仅占19.6%。加入季节、年份随机效应的LMEM模型对于小黄鱼体长和性成熟概率关系的拟合效果最好,AIC值和RMSE值最小。模型结果表明:季节对小黄鱼性成熟概率和体长关系的影响最显著,50%的性成熟体长(L_(50%))值在冬季最小(124.6 mm),其他季节差异不明显,冬季性成熟速度最快。本研究表明,线性混合效应模型能较好地反映小黄鱼的生物学异质性,小黄鱼生长和性成熟具有显著的季节变化,在进行渔业资源评估和管理时应予以充分考虑。

The variations of life history traits have been observed for many fish species,which gains much concerns in the study of aquatic biology and ecology.In this study,the biological characteristics were explored for yellow croaker(Larimichthys polyactis)in the offshore waters of southern Zhejiang,based on 4920 individuals collected from 13 fishery-independent seasonal surveys from autumn 2015 to autumn 2018.Linear mixed effects models were used to estimate the growth,maturity characteristics,and their heterogeneity.The body length of yellow croaker samples ranged from 13 to 215 mm with the dominant body of 110 to 154 mm.The body weight ranged from 0.5 to 182.2 g,with the dominant body weight from 20 to 55 g.The results showed that the linear mixed effects models with random effects from season,gender,and year performed best for length-weight relationship,with the lowest AIC and RMSE values.The effects of season were much larger than those of genders and years.When the length exceeded 160 mm,the weight gain rate of yellow croaker was faster in spring and summer,lower in autumn and winter,while the male individuals gained more weight than the females with the same body length.Among 4841 individuals of specimens with gonadal data,the individuals at maturityⅡstage occupied 50.4%,and the individuals at maturity stage contributed to 19.6%.The results from the best linear mixed effects model showed that season had the most significant influence on the maturity of yellow croaker.The 50%maturity length(L_(50%))was much lower in winter(124.6 mm)with no much difference between other seasons,indicating that yellow croaker matures earlier in winter.Our results indicated that linear mixed effect model could reflect the biological heterogeneity of yellow croaker conveniently and that the growth and maturity of yellow croaker had significantly sexual and temporal variations,which should be considered in the stock assessment and fishery management for yellow croaker.