Leaving the fish bowl: the ornamental trade as a global vector for freshwater fish invasions

Despite its social and economic benefits, the trade in ornamental species (henceforth, ‘ornamental trade’) has become a major source of non-native fish introductions into freshwater ecosystems. However, the ornamental trade as a vector for introductions of non-native freshwater fishes is not well defined. We developed a framework incorporating elements of the biological invasion process and a typical ornamental fish trade supply chain to fill this gap. Records of non-native ornamental fishes introduced to freshwater environments of Australia, Belgium (Flanders), Canada (British Columbia), China (Guangdong), the Philippines, Poland, Singapore, the United Kingdom (England), and the United States of America (Florida) were reviewed to explore the pervasiveness of these introduced fishes in the wild. These regional case studies confirmed the prominence of the ornamental trade as a global vector for freshwater fish introductions beyond their natural range. Additionally, we examined freshwater fishes associated with the ornamental trade to identify ‘risky’ species that could establish in recipient regions based on climate match. All regions assessed were at risk of new fish introductions via the ornamental trade, with the number of ‘risky’ species ranging from seven to 256. Further, there appears to be taxonomic bias in the freshwater ornamental fish trade, with 74% of the species belonging to just 10 families (of 67). Current prevention and management approaches and associated polices, regulations and legislation on aquatic non-native species within assessed regions fit five general categories: import controls, risk assessment, whitelist, blacklist, and release ban. However, these prevention/management efforts may not be sufficient to reduce the invasion risk associated with the ornamental fish trade. Recommendations including species- and vector-based risk assessments, better recording of species import consignments, increased public education and industry engagement, and early detection and rapid response are discussed in this review.

尽管观赏物种贸易（ornamental trade）兼具社会与经济效益，但其已成为外来鱼类入侵淡水生态系统的主要途径之一。然而，观赏鱼贸易作为外来淡水鱼类入侵的传播媒介，其具体作用机制尚未得到清晰界定。为此，本研究整合生物入侵过程与典型观赏鱼贸易供应链的核心要素，构建了一套分析框架以填补这一研究空白。本研究梳理了澳大利亚、比利时（法兰德斯地区）、加拿大（不列颠哥伦比亚省）、中国（广东省）、菲律宾、波兰、新加坡、英国（英格兰地区）以及美国（佛罗里达州）的外来观赏鱼类入侵淡水环境的相关记录，以探究这些外来鱼类在野外的普遍分布情况。上述区域案例研究证实，观赏鱼贸易作为全球范围内淡水鱼类突破自然分布范围实现入侵的重要媒介，其地位不容忽视。此外，本研究针对观赏鱼贸易相关的淡水鱼类展开分析，基于气候匹配度筛选出可能在接收区域成功定殖的“高风险”物种。所有受访区域均面临通过观赏鱼贸易新增鱼类入侵的风险，其高风险物种数量介于7至256种之间。进一步分析显示，淡水观赏鱼贸易存在显著的分类学偏向：在总计67个科中，74%的物种仅隶属于其中10个科。受访区域当前针对水生外来物种的预防与管理手段，以及配套政策、法规与立法工作，可归纳为五大类：进口管制、风险评估、白名单、黑名单以及放生禁令。然而，此类预防与管理措施或不足以降低观赏鱼贸易带来的入侵风险。本综述最后提出多项建议，包括开展基于物种与传播媒介的风险评估、完善物种进口货物记录、加强公众教育与行业协作、建立早期监测与快速响应机制。