東沙群島海域魚類名錄
摘要
東沙群島位於南中國海北部，為我國設立之海洋保護區。其環礁棲地為許多珊瑚礁魚類的重要育幼場所。同時，外海深海大陸棚海域則盛產各種深海魚類，為歷史上重要的漁場。雖然過去台灣的魚類研究主要集中於珊瑚礁魚類，包括記錄73科共652種，但對於深海魚類的調查較為缺乏。本研究透過分析2021–2025年於東沙海域作業的商業深海拖網漁船所捕獲的混獲魚類樣本，以及檢視既有文獻，更新東沙海域魚類種類組成。結果顯示，魚類名錄增加至 167 科共1087 種，包含新記錄種以及可能尚未描述的新種。本名錄同時收錄各魚種的照片以及矢狀耳石，除了有利後續各領域的研究，亦大幅提升對南中國海魚類相的了解。
方法與執行步驟
Our study used two distinct datasets: occurrence records from the literature on coral and seagrass-associated shallow-water fishes and newly collected occurrence data from deep-water fishes sampled via commercial bottom trawlers. Both datasets represent different ecological settings with distinct sampling techniques. For the former, we reviewed existing literatures and validated nomenclatures. From February to early July each year from 2021 to 2024, we obtained frozen samples from fishermen at Zhengbin fish port in Keelung, Taiwan that were collected from the commercial bottom trawlers operating in the waters off Dongsha Island at depths of approximately 300–600 meters (18°49'N to 20°45'N and 112°46'E to 116°15'E). These samples consisted mainly of fishes and other invertebrates and weighed approximately 30 kg each. The total samples (n = 198) processed collectively weighed more than 6,000 kg. We collected samples bi-monthly, carefully selecting specimens to ensure they represented the broadest possible diversity within the catch. These samples were then transferred to our lab and defrosted sequentially.
Each fish was measured for standard length (SL), total length (TL), and weight (WT), with preanal length (PAL) recorded when necessary. Specimens were photographed before muscle tissue was subsampled from the right caudal region. These tissue samples were preserved in 95% ethanol and deposited at the National Academy of Marine Research in Kaohsiung for future reference.
For images of teleostean otoliths, the left sagittal otoliths were primarily used; right otoliths were reversed for consistency and noted with an (R) in each caption. These otoliths were coated with a thin layer of gold using an ion sputter machine (MCM-100P, Sec, South Korea) to enhance the visibility of the sulcus. In addition, images of small-sized otoliths were captured using a scanning electron microscope (JSM-7100FLV, Jeol, Japan). Otoliths were archived at the Marine Paleontology Lab, Biodiversity Research Center, Academia Sinica, registered under the code CHLOL. Scientific names and taxonomic attributions adhere to the latest edition of the Catalog of Fishes. Our remarks provide information on species distribution and abundance estimates around Dongsha Island.
創新作為與跨域合作
The earliest record of the ichthyofauna around Dongsha Island was around 30 years ago, which was later incorporated by Randall and Lim (2000) into a comprehensive checklist of South China Sea fishes. Despite updates by Shao et al. (2008, 2011) in their checklists for southern Taiwan and the northern South China Sea, there has until now been no concerted effort to synthesize new data from subsequent studies. Our study presents the most exhaustive inventory to date, utilizing existing literature and newly sampled fish collections conducted between 2021 and 2024. More importantly, this is the first attempt to target samples derived from commercial fisheries, which operate with much higher fishing effort, generate larger catches using bigger fishing gear, and more broadly cover deeper and remote areas compared to typical scientific research vessels. Thus, our results provide novel insights and deeper knowledge of the fish fauna around Dongsha Island, especially for the less explored western waters off the atoll. Additionally, this study provides actual images and otoliths of the fishes from Dongsha Island, offering a tool for species identification, and as reference to other fields such as paleontology.
預期成果與貢獻
In this study, we cataloged a total of 1087 species across 167 families, and our recent efforts alone identified 337 species from 93 families. Thirteen species have been described from 2021 to 2024 around Dongsha Island, and 89 species have been newly recorded in this study, with 35 species still undescribed and requiring further investigation. The updated checklist not only enriches our understanding of marine biodiversity but also serves as a critical resource for future research and conservation initiatives. Notably, based on the IUCN Red List of Threatened Species (IUCN 2012), there were two fish species recorded in Dongsha Island that were considered Critically Endangered; nine species are listed as Endangered; ten as Vulnerable; and six as Near Threatened. However, most species were categorized as Least Concern or Data Deficient, highlighting the need for continued research and conservation efforts to ensure sustainable fishing practices in the region.
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