Genetic evidence challenges the native status of a threatened freshwater fish (Carassius carassius) in England

• Published in: Ecology and evolution 2017-05, Vol.7 (9), p.2871-2882
• Main Authors: Jeffries, Daniel L., Copp, Gordon H., Maes, Gregory E., Lawson Handley, Lori, Sayer, Carl D., Hänfling, Bernd
• Format: Article
• Language: English
• Subjects: Approximate Bayesian Computation; Bayesian analysis; Carassius carassius; Carp; Colonization; Conservation; Fish; Fish conservation; Freshwater fish; Genetics; introduced species; land bridge; microsatellites; Original Research; Origins; Population structure; postglacial recolonization; Species; Threatened species; Wildlife conservation
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.2831

A fundamental consideration for the conservation of a species is the extent of its native range, that is, regions naturally colonized. However, both natural processes and human‐mediated introductions can drive species distribution shifts. Ruling out the human‐mediated introduction of a species into a given region is vital for its conservation, but remains a significant challenge in most cases. The crucian carp Carassius carassius (L.) is a threatened freshwater fish thought to be native to much of Europe. However, its native status in England is based only on anecdotal evidence. Here, we devise an approach that can be used to empirically test the native status of English fauna. We use this approach, along with 13 microsatellite loci, population structure analyses, and Approximate Bayesian Computation (ABC), to test hypotheses for the origins of C. carassius in England. Contrary to the current consensus, we find strong support for the human‐mediated introduction of C. carassius into England during the 15th century. This result stimulates an interesting and timely debate surrounding motivations for the conservation of species. We discuss this topic, and the potential for continued conservation of C. carassius in England, despite its non‐native origins. Carassius carassius, the crucian carp, is a highly endangered species throughout most of its range, and as such, it is actively conserved in England. However, there are doubts as to whether crucian carp are indeed native in England. Molecular data and analyses performed in this study suggest that these doubts are well founded and that crucian carp were indeed introduced to England by humans, approximately 500 years ago. This result raises an interesting discussion regarding our motivations for conserving species.