Chu Cecilia, Loh Kar Hoe, Ng Ching Ching, Ooi Ai Lin, Konishi Yoshinobu, Huang Shih-Pin, Chong Ving Ching
Institute of Ocean and Earth Sciences, University of Malaya, Kuala Lumpur, Malaysia. E-mail:
Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
Zool Stud. 2019 Oct 18;58:e30. doi: 10.6620/ZS.2019.58-30. eCollection 2019.
Larval descriptions of tropical marine and coastal fishes are very few, and this taxonomic problem is further exacerbated by the high diversity of fish species in these waters. Nonetheless, accurate larval identification in ecological and early life history studies of larval fishes is crucial for fishery management and habitat protection. The present study aimed to evaluate the usefulness of DNA barcodes to support larval fish identification since conventional dichotomous keys based on morphological traits are not efficient due to the lack of larval traits and the rapid morphological changes during ontogeny. Our molecular analysis uncovered a total of 48 taxa (21 families) from the larval samples collected from the Klang Strait waters encompassing both spawning and nursery grounds of marine and estuarine fishes. Thirty-two (67%) of the larval taxa were identified at the species level, two taxa (4%) at the genus level, and 14 taxa (29%) at family level. The relatively low rate of species-level identification is not necessarily due to the DNA barcoding method , but a general lack of reference sequences for speciose and non- commercial fish families such as Gobiidae, Blenniidae, and Callionymidae. Larval morphology remains important in species diagnoses when molecular matches are ambiguous. A lower ethanol percentage (50%) for larva preservation is also useful to keep the body of larvae intact for morphological identification, and to preserve DNA for subsequent molecular analyses. The 10% Chelex resin used to extract DNA is also cost- effective for long term monitoring of larval fishes. Hence, the DNA barcoding method is an effective and easy way to aid the identification of estuarine larval fishes at the species level.
热带海洋和沿海鱼类幼体的描述非常少，而且这些水域中鱼类物种的高度多样性进一步加剧了这一分类学问题。尽管如此，在幼体鱼类的生态和早期生活史研究中，准确识别幼体对于渔业管理和栖息地保护至关重要。本研究旨在评估DNA条形码在支持幼体鱼类识别方面的有效性，因为基于形态特征的传统二分检索表由于缺乏幼体特征以及个体发育过程中形态的快速变化而效率不高。我们的分子分析从巴生海峡水域采集的幼体样本中总共发现了48个分类单元（21个科），这些水域包括海洋和河口鱼类的产卵场和育幼场。其中32个（67%）幼体分类单元在物种水平上得到鉴定，2个分类单元（4%）在属水平上得到鉴定，14个分类单元（29%）在科水平上得到鉴定。物种水平鉴定率相对较低不一定是由于DNA条形码方法，而是因为对于一些物种丰富且非商业性的鱼类科，如虾虎鱼科、鳚科和龙鰧科，普遍缺乏参考序列。当分子匹配不明确时，幼体形态在物种诊断中仍然很重要。较低乙醇百分比（50%）保存幼体也有助于保持幼体身体完整以进行形态鉴定，并保存DNA用于后续分子分析。用于提取DNA的10% Chelex树脂对于幼体鱼类的长期监测也是经济有效的。因此，DNA条形码方法是在物种水平上辅助鉴定河口幼体鱼类的一种有效且简便的方法。
