Management of Biological Invasions (2013) Volume 4, Issue 4: 265–271 doi: http://dx.doi.org/10.3391/mbi.2013.4.4.01 © 2013 The Author(s). Journal compilation © 2013 REABIC Open Access 265 Research Article A non-native snakehead fish in British Columbia, Canada: capture, genetics, isotopes, and policy consequences David Scott 1 , Jonathan W. Moore 2 *, Leif-Matthias Herborg 3 , Cathryn Clarke Murray 4 and Natasha R. Serrao 5 1 School of Resource and Environmental Management, Simon Fraser University, V5A 1S6, Burnaby, BC, Canada 2 Earth to Ocean Research Group, Simon Fraser University, V5A 1S6, Burnaby, BC, Canada 3 BC Ministry of Environment, PO Box 9338 Stn Prov Govt, V8W 9M1, Victoria, BC, Canada 4 Institute for Resources, Environment and Sustainability, University of British Columbia, 2202 Main Mall, V6T 1Z4, Vancouver, BC, Canada 5 Department of Integrative Biology, University of Guelph, 50 Stone Road East, N1G 2W1, Guelph ON, Canada E-mail: dcscott@sfu.ca (DS), jwmoore@sfu.ca (JWM), Matthias.Herborg@gov.bc.ca (LMH), cclarke@eos.ubc.ca (CCM) natashaserrao@trentu.ca (NRS) *Corresponding author Received: 1 August 2013 / Accepted: 28 October 2013 / Published online: 25 November 2013 Handling editor: Justin MacDonald Abstract In June 2012 a single non-native snakehead fish was captured by local officials in a small pond within an urban park in Burnaby, British Columbia. This single snakehead fish garnered significant attention in the local and national media. DNA analysis determined it to be a blotched snakehead (Channa maculata) or possibly a hybrid; a warm water species native to China and Vietnam which is commonly sold in the live food fish trade, and occasionally kept by hobbyists. By collecting prey items from the pond and snakehead specimens from fish markets we used a novel stable isotope approach to estimate how long it had been since the snakehead had been released into the pond. Using a diet-switching tissue turnover model, we estimated that the snakehead was in the pond between 33 and 93 days. Subsequently, provincial legislation was amended to ban all species of snakehead fish, as well as numerous other potentially invasive fish and invertebrate species. Key words: stable isotope analysis; tissue turnover model; failed invasion; invasion pathways; Fraser River Introduction Invasive species are generally studied only after they have become established and spread (Zenni and Nuñez 2013), leaving an absence of studies focusing on the first phases of invasion: transport and introduction (Kolar and Lodge 2001). Once a species has proliferated and caught the attention of managers or scientists, it can be difficult to reconstruct critical information regarding key initial phases of introduction (but see Cadien and Ranasinghe 2001). Furthermore, these initial phases of invasion tend to filter out the vast majority of most potential exotic species from those that could be invasive. Only about 1% of new non-native imports become invasive (Williamson 2006). Studies of potentially harmful non-native species in the initial phases of invasion, including species that fail to establish and spread, can thus advance our understanding of the processes that underpin potential invaders (Zenni and Nuñez 2013). Further understanding of invasive pathways could be particularly useful for preventing the release and establishment of species identified as emerging threats such as the snakehead group of fish (Family: Channidae) (Courtenay and Williams 2004; Herborg et al. 2007). This family consists of 29 species of two genera with home ranges in Southeast Asia, Russia and Africa (Courtenay and Williams 2004). To date there have been numerous introductions in North America, including populations of blotched snakeheads (Channa maculata Lacepède, 1801)