Detecting aquatic invasive species in bait and pond stores with targeted environmental (e) DNA high-throughput sequencing metabarcode assays: angler, retailer, and manager implications

Bait and pond stores comprise potential, yet poorly understood, vectors for aquatic invasive species (AIS). We tested for AIS and illegal native species in 51 bait and 21 pond stores from the central Great Lakes (Lake Erie, Ohio and Lake St. Clair, Michigan) and the adjacent Wabash River (Indiana) using environmental DNA (eDNA) metabarcode assays of water samples and morphological identifications. Retailers were questioned about supply chains, and anglers surveyed about baitfish use and disposal. Assays revealed unadvertised species eDNA in 100% of bait stores, with 61% containing illegal native non-bait (totaling 13 species) and 88% having AIS (11 species). Illegal native non-bait species included juvenile walleye, yellow perch, and white sucker eDNA. AIS eDNA included Eurasian ruffe in seven stores (all states), silver carp in five (including a Lake Erie store in two separate years), and bighead carp in two Lake Erie stores that also had silver carp. Among pond stores, two in Lake St. Clair had bighead carp eDNA, one also contained silver carp, and a Wabash River location showed European ide. Unadvertised invasive snails were discerned in 55% of pond stores. Four contained zebra mussel eDNA and two had invasive bryozoans. Illegal native species and AIS were widespread, but showed little relationship to the retailers’ variable and extensive supply chains. Live baitfish releases were reported by 50% of Lake Erie anglers and 35% in Lake St. Clair. Consumer behavior and AIS prevalence in the bait and pond trades thus pose serious risks for introductions and spread.

渔具店与水族店是水生入侵物种（Aquatic Invasive Species，AIS）潜在却尚未被充分认知的传播媒介。本研究针对五大湖中部（俄亥俄州伊利湖、密歇根州圣克莱尔湖）及邻近印第安纳州沃巴什河流域的51家渔具店与21家水族店，采用水样环境DNA（environmental DNA，eDNA）元条形码检测法与形态学鉴定手段，开展水生入侵物种与非法本土物种检测。研究人员向零售商询问了供应链相关信息，并对垂钓者开展了关于活饵使用与处置方式的问卷调查。检测结果显示，所有渔具店均检出未对外公示的物种的eDNA，其中61%的店铺存在非法本土非饵料物种（共计13种），88%的店铺检出AIS（共计11种）。非法本土非饵料物种的eDNA包括幼体大眼梭鲈、黄鲈与白吸口鱼的eDNA。检出的AIS eDNA包括覆盖所有调研区域的7家店铺中的欧亚鲈鱼（Eurasian ruffe）、5家店铺中的银鲤（silver carp），其中一家伊利湖店铺在两次独立采样中均检出，以及同时检出银鲤的两家伊利湖店铺中的鳙（bighead carp）。在水族店中，圣克莱尔湖的两家店铺检出鳙的eDNA，其中一家同时检出银鲤；沃巴什河流域的一家店铺检出高体雅罗鱼（European ide）。55%的水族店检出未对外公示的入侵螺类，其中4家检出斑马贻贝（zebra mussel）的eDNA，2家检出入侵苔藓虫。非法本土物种与AIS分布广泛，但与零售商复杂多变的供应链几乎无关联。伊利湖的垂钓者中有50%报告曾放生活饵料鱼，圣克莱尔湖的垂钓者中这一比例为35%。综上，渔具与水族贸易中的消费者行为及AIS的流行程度，为物种引入与扩散带来了严峻风险。