Abstract Morphological species identification in juvenile Scylla is now possible using image analysis of frontal lobe spines. The differences found are subtle and require automation using a mobile application. Considering the bulk of crablets to be sorted for trading, distinct features that can help stakeholders distinguish the species of juveniles at a glance is still needed. In this study, morphometric analysis of dorsal carapace features was performed to identify more obvious features for species identification. Principal component analysis of ten morphometric characters from 1186 juveniles revealed only two clusters with Scylla olivacea creating a separate group from S. tranquebarica and S. serrata. The most distinguishable ratio for S. olivacea, determined through discriminant analysis and ANOVA, was the ratio of the frontal median spine height to the frontal width at 0.035 (p = 0.002). There is an emerging market for S. olivacea in the soft-shell crab industry. Selection of this smaller but useful species can aid fishers in setting appropriate prices for traded crablets and minimize predation to the larger S. tranquebarica and S. serrata. Testing if the ratio can be detectable by visual approximation is ongoing as well as alternative features based on local practices.

中文翻译：

---

通过自动化和局部方法对幼年红树林蟹（Scylla 属）物种形态学鉴定的比较

摘要 现在可以使用额叶刺的图像分析来识别幼鱼的形态学物种。发现的差异很微妙，需要使用移动应用程序实现自动化。考虑到大量的小蟹需要分拣进行交易，仍然需要能够帮助利益相关者一目了然区分幼蟹种类的独特特征。在这项研究中，对背甲特征进行了形态计量分析，以识别更明显的物种识别特征。对来自 1186 只幼鱼的 10 个形态特征的主成分分析显示，只有两个簇与 Scylla olivacea 创建了一个单独的组，与 S. tranquebarica 和 S. serrata。通过判别分析和方差分析确定的 S. olivacea 最可区分的比率，是正面正中脊柱高度与正面宽度之比为 0.035 (p = 0.002)。S. olivacea 在软壳蟹行业有一个新兴市场。选择这种较小但有用的物种可以帮助渔民为交易的小蟹设定适当的价格，并最大限度地减少对较大的 S. tranquebarica 和 S. serrata 的捕食。正在测试该比率是否可以通过视觉近似检测以及基于当地实践的替代特征。