Sometimes conservation needs a good villain
By Cathryn Clarke Murray, Marine Science Officer
Enter the snakehead fish – in June 2012 it became a media celebrity after a YouTube video showed the highly invasive fish comfortably enjoying a Burnaby municipal pond. Our villain seemingly comes straight from a horror movie; dubbed “fishzilla” by National Geographic, it has razor sharp teeth and can survive short periods out of water to thrash its way to new waterbodies. Our heros? A huge team from BC Ministry of Environment, Vancouver Park Board, University of British Columbia and Simon Fraser University (SFU) was deployed to catch the fish…cue fanfare, spectators and even our own media coordinator! As part of the team, I had the muddy experience of seining the pond and systematically emptying it of hundreds of non-native animals including carp, goldfish, fathead minnows, brown catfish and bullfrog tadpoles and, thank goodness, we caught that one lonely snakehead.
But then the hard science began. Specialists at SFU used stable isotope analysis to see how long the fish had been in the pond and what it was eating. Genetics experts at University of Guelph and taxonomists at University of British Columbia determined which species of snakehead it was. My job, to find out where the villain came from, took me to the exotic field settings of Vancouver’s urban grocery stores, aquarium shops and Chinatown markets. I was amazed to see the variety of live seafood available to purchase in the markets, but staggered by the hundreds of species in the aquarium stores. While access to this diversity is a bonus for customers, if released into our oceans, rivers or lakes non-native species can have devastating impacts on our native biodiversity.
Our results, published this week in the Journal Management of Biological Invasions, revealed that our villain was a blotched snakehead, rather than the feared Northern snakehead, which is unlikely to be able to survive our winters. Native to Vietnam and southern China, it was 3.7 kilograms but can grow to over a metre in length. Stable isotope analysis showed that the fish was only in the pond for 2-3 months and was feeding on the local pond species, most of which were also non-native species. The specimen did not contain any eggs and therefore it was likely not breeding in the pond. All good news. I found that blotched snakehead fish were available for sale in both the markets and through aquarium shops but results of our questionnaires indicate that the Burnaby pond snakehead was likely released by a well-intentioned pet owner.
This horror story seemingly has a happy ending: a quick response by provincial officials removed the threat and prevented the possibility of an invasion. Even better? The publicity generated by fishzilla resulted in important changes to the BC Provincial Wildlife Act which now bans the possession, transport and breeding of all species of snakehead and anyone caught releasing one could be handed a $250,000 fine. The list also bans another dozen troubling, if less photogenic, species such as oriental weatherfish, Western mosquitofish, and the zebra and quagga mussels.
