Abstract:
A size-based, histological analysis of the reproductive life history of the blacktip grouper, Epinephelus fasciatus (Forsskål 1775), was conducted in Indonesia to evaluate the error rate associated with macroscopic reproductive analysis. Histological results indicated that E. fasciatus was protogynous with female L50 at 13.4 cm total length (LT) and a size at sexual transition of 22.0 cm LT. The weight-length relationship for the species was W = 0.011 L3.13. Overall sex ratios were significantly female biased, operational sex ratios were significantly male biased, and sex ratios of mature individuals varied predictably with length from female to male dominance as size increased. No significant relationship between length and batch fecundity was found. The population has a spawning period from February to August. Overall, 54.4% of macroscopic evaluations were incorrect compared to histological results. Of the errors, 14.8% were a failure to detect ovotestes, 12.7% were classifying non-gonadal tissue as ovary or testis, 12.2% were misclassifying sex, and 12.7% were misclassifying maturity status. However, the largest source of error (47.7%) was from misclassifying both sex and maturity status. Of these, 92.9% were macroscopically classified as immature females, but were histologically confirmed to be mature males. Compared to histological results, the only accurate macroscopic results were the absence of a sex-based difference in weight-length relationship and spawning seasonality estimated by a gonadosomatic index (February-June). The use of macroscopic methods to estimate reproductive life-history parameters for sex-changing reefes fish may introduce significant inaccuracies and misinterpretations. Of the parameters estimated by histological methods, size at maturity, size-specific sex ratios, and spawning seasonality have the greatest potential to inform local fishery management policy.
摘要:
基于大小的,黑头石斑鱼生殖生活史的组织学分析,Epinephelusfasciatus(福斯克1775),在印度尼西亚进行,以评估与宏观生殖分析相关的错误率。组织学结果表明,筋膜E.fasciatus与雌性L50同质,总长度(LT)为13.4cm,性过渡时的大小为22.0cmLT。该物种的体重-长度关系为W=0.011L3.13。总体性别比例有明显的女性偏见,操作性别比例明显有男性偏见,随着年龄的增加,成熟个体的性别比例会随着从女性到男性的长度而变化。在长度和批次繁殖力之间没有发现显着关系。人口的产卵期为2月至8月。总的来说,与组织学结果相比,54.4%的宏观评估不正确。在错误中,14.8%是未能检测到Ovotestes,12.7%将非性腺组织分类为卵巢或睾丸,12.2%的人性别分类错误,12.7%的人对到期状态进行了错误分类。然而,最大的错误来源(47.7%)是性别和成熟状态的错误分类.其中,92.9%被宏观分类为未成熟的女性,但组织学证实是成熟男性。与组织学结果相比,唯一准确的宏观结果是通过性腺指数(2-6月)估计的体重-身长关系和产卵季节没有基于性别的差异.使用宏观方法估算变性鱼的生殖生活史参数可能会导致严重的不准确和误解。在组织学方法估计的参数中,成熟时的大小,特定大小的性别比例,产卵季节性最有可能为当地渔业管理政策提供信息。