海洋高階掠食魚類的市場調查與檢驗方法改進 – 鯊與鮪

Abstract

鯊魚和鮪魚等頂級掠食性魚類在維持海洋食物網穩定性扮演至關重要角色。然而，商業漁撈與高市場需求已對它們的生態功能構成威脅。因此，需要有效的物種檢測方法來建立有效的漁業管理。本研究使用粒線體細胞色素c氧化酶次單元I（Cytochrome c oxidase subunit I, COI）DNA條形碼來確定魚翅乾貨的市場分布情況，提供乾貨市場中鯊魚物種組成的重要資訊。此外，本研究也利用粒線體基因來開發檢測南方黑鮪（Thunnus maccoyii）的恆溫式圈環形核酸增幅法（LAMP）。乾魚翅抽樣結果顯示，鋸峰齒鮫（Prionace glauca）佔逾六成乾魚翅貨源。雖然2017年起臺灣實施了更嚴格的漁業管理法律，但受保護和瀕危物種製成的乾魚翅仍在乾貨店出售，如：平滑白眼鮫（Carcharhinus falciformis）、污斑白眼鮫（Carcharhinus longimanus）、紅肉丫髻鮫（Sphyrna lewini），佔逾兩成。而在針對平滑白眼鮫（Carcharhinus falciformis）的抽樣結果顯示約有兩成贗品率，顯示管理政策仍有可改善空間。本研究儘管測試了不同基因、引子與DNA黏合溫度、引子組和反應時間，但南方黑鮪LAMP法未能區分不同鮪魚物種。這顯示基於粒線體基因開發的LAMP方法可能不適用於南方黑鮪的物種鑑定。

Top predatory fishes, such as sharks and tuna, play a crucial role in maintaining the stability of marine food webs. However, their ecological function is threatened by fishing activity and high market demand. Therefore, it is imperative to employ effective species detection methods to enhance fishery management. In this study, mitochondrial Cytochrome c oxidase subunit I (COI) DNA barcoding was used to identify the market status of dried shark fins, providing insights into the composition of shark species in the market. Furthermore, an attempt was made to develop loop-mediated isothermal amplification (LAMP) as a detection tool for southern bluefin tuna (Thunnus maccoyii) using mitochondrial genes i.e. ND5 (NADH dehydrogenase 5) and D-loop regions. Despite the implementation of stricter fishing laws, the sale of shark fins derived from protected and endangered species, e.g. silky shark (Carcharhinus falciformis), oceanic whitetip shark (Carcharhinus longimanus), scalloped hammerhead (Sphyrna lewini) continues in retail stores, highlighting the necessity for policy revisions. In the case of the LAMP assay for southern bluefin tuna, various approaches were explored, including testing different genes, annealing temperatures, primer sets, and reaction times. Nevertheless, these efforts failed to distinguish between different tuna species. This outcome suggests that the LAMP assay based on mitochondrial genes may not be suitable for accurately identifying southern bluefin tuna.