Data from: DNA barcoding of the ichthyofauna of Taal Lake, Philippines

This study represents the first molecular survey of the ichthyofauna of Taal Lake and the first DNA barcoding attempt in Philippine fishes. Taal Lake, the third largest lake in the Philippines, is considered a very important fisheries resource and is home to the world’s only freshwater sardine, Sardinella tawilis. However, over-exploitation and introduction of exotic fishes have caused a massive decline in the diversity of native species as well as overall productivity of the lake. In this study, 118 individuals of 23 native, endemic, and introduced fishes of Taal Lake were barcoded using the partial DNA sequence of the mitochondrial cytochrome oxidase I (COI) gene. These species belong to 21 genera, 17 families and 9 orders. Divergence of sequences within and between species was determined using Kimura 2-parameter (K2P) distance model and a neighbor-joining tree was generated with 1000 bootstrap replications using the K2P model. All COI sequences for each of the 23 species were clearly discriminated among genera. The average within species, within genus, within family, and within order percent genetic divergence was 0.60%, 11.07%, 17.67%, and 24.08%, respectively. Our results provide further evidence that COI DNA barcodes are effective for rapid and accurate identification of fishes and for identifying certain species that need further taxonomic investigation.

本研究为塔尔湖（Taal Lake）鱼类区系的首次分子调查，同时也是菲律宾鱼类领域首次开展的DNA条形码（DNA barcoding）研究尝试。塔尔湖作为菲律宾第三大湖泊，是极具价值的渔业资源载体，同时孕育了全球唯一的淡水沙丁鱼——塔威沙丁（Sardinella tawilis）。然而，过度捕捞与外来鱼类引种已导致该湖原生物种多样性大幅下降，湖泊整体渔业生产力亦随之锐减。本研究针对塔尔湖的23种原生、特有及引入鱼类的118个个体，利用线粒体细胞色素氧化酶I（COI）基因的部分DNA序列开展了条形码分析。所涉物种分属21个属、17个科及9个目。本研究采用Kimura双参数（K2P）距离模型计算了物种内及物种间的序列差异，并基于该模型构建了包含1000次自展重复的邻接进化树。23个物种的全部COI序列均可在属水平上得到清晰区分。物种内、属内、科内及目内的平均遗传分化率分别为0.60%、11.07%、17.67%与24.08%。本研究结果进一步证实，COI DNA条形码可实现鱼类的快速精准鉴定，同时可为部分亟待开展分类学深入研究的物种提供识别依据。