Herath D R, Perera H A C C, Ranasinghe V K, Amarakoon A A D G, Hettiarachchi G H C M
Marine Biological Resources Division, National Aquatic Resources Research and Development Agency (NARA), Colombo 15, Sri Lanka.
Department of Chemistry, Faculty of Science, University of Colombo, Colombo 3, Sri Lanka.
Mol Biol Rep. 2024 Dec 18;52(1):63. doi: 10.1007/s11033-024-10151-1.
Analysis of the content of the gut of fish helps in the understanding of their inter- and intra-specific interactions, fish behaviour, condition and energy intake. The stomach contents of the commercially important neritic tuna species of Sri Lanka, kawakawa (Euthynnus affinis), frigate tuna (Auxis thazard) and bullet tuna (Auxis rochei) were analysed to determine their feeding habits and to identify prey species.
The weighed stomachs of fish were dissected to reveal the types of prey found within. The prey was categorised into prey categories and each prey species was identified morphologically. Prey items which were partially digested were identified using DNA barcoding. The main prey category was small fish, followed by crustaceans and cephalopods. While the highest occurring prey category for E. affinis and A. rochei was fish, crustaceans dominated the A. thazard diet. DNA barcoding identified 11 prey items that were partially digested, which could not be identified to species-level morphologically. Of the prey items identified by DNA barcoding, four species of fish, three species of cephalopod and four species of crustaceans were identified. These prey item identifications confirmed that E. affinis, A. thazard and A. rochei are all nonspecific feeders.
This exhibits the value of molecular tools in the identification of species which have lost their distinguishable features due to digestion. Further, it illustrates the predator-prey relationships between these species, aiding in the management of prey and predator populations, ensuring that both populations remain stable, helping in the maintenance of the balance of the ecosystem.
分析鱼类肠道内容物有助于理解它们的种间和种内相互作用、鱼类行为、身体状况和能量摄入。对斯里兰卡具有商业重要性的近岸金枪鱼物种卡瓦卡瓦（Euthynnus affinis）、扁舵鲣（Auxis thazard）和圆舵鲣（Auxis rochei）的胃内容物进行分析，以确定它们的摄食习性并识别猎物种类。
对鱼的胃称重后进行解剖，以揭示其中发现的猎物类型。猎物被分类为不同的猎物类别，并对每个猎物物种进行形态学鉴定。对于部分消化的猎物，使用DNA条形码进行鉴定。主要的猎物类别是小鱼，其次是甲壳类动物和头足类动物。虽然卡瓦卡瓦和圆舵鲣出现频率最高的猎物类别是鱼类，但扁舵鲣的食物中甲壳类动物占主导。DNA条形码鉴定出11种部分消化的猎物，这些猎物在形态学上无法鉴定到物种水平。在通过DNA条形码鉴定出的猎物中，鉴定出了4种鱼类、3种头足类动物和4种甲壳类动物。这些猎物鉴定结果证实，卡瓦卡瓦、扁舵鲣和圆舵鲣都是非特定性捕食者。
这展示了分子工具在鉴定因消化而失去可区分特征的物种方面的价值。此外，它阐明了这些物种之间的捕食者 - 猎物关系，有助于管理猎物和捕食者种群，确保两个种群都保持稳定，有助于维持生态系统的平衡。
