The "frankenfish" that generated international attention when video of it swimming in a Burnaby pond surfaced on YouTube was likely not a northern snakehead after all, says a new study.
But researchers say the fish – which was most likely a blotched snakehead that might not have survived the winter – still feasted on other species during its time in the pond, and could have yielded more serious consequences if it found its way into the Fraser River.
The study, published in the Management of Biological Invasions Journal, provides the most complete picture yet of the fish's highly publicized stint in Burnaby's Central Park.
The study says the toothy predator was in the pond for one to three months before it was captured in June of last year – a capture that took a team of officials approximately 300 hours in total staff time.
Researchers weren't able to determine the fish's age or sex, but no evidence of eggs was found in the pond. The study says the fish ate other non-native inhabitants that had also been dumped into the waterway, including goldfish and minnows.
David Scott, the study's lead author and a Master's student at Simon Fraser University's School of Resource and Environmental Management, said DNA testing determined the fish was likely a blotched snakehead, not a northern snakehead as initially believed. He said it remains possible the fish was a hybrid, but researchers are "pretty confident" it was a blotched snakehead.
Mr. Scott said blotched snakeheads have generally received less attention in Canada than northern snakeheads because the former typically does not live in cold water. However, he said blotched snakeheads have not been well studied and some that have been introduced in Japan have shown they can survive outside their perceived thermal limits.
Mr. Scott said the blotched snakehead is similar in size to the northern snakehead – the one captured in Burnaby was a half-metre long and weighed more than three-and-a-half kilograms – and eats a variety of prey.
"It could have possibly been just as bad as it could have been with a northern snakehead," he said in an interview Sunday.
Snakeheads are typically found in Asia or Africa, but are sometimes purchased as pets. Mr. Scott said because the fish can spend days out of water – as long as it's kept moist – and is generally viewed as hardy, some believe its flesh has a rejuvenating property and eat it.
When the fish was first spotted in the Burnaby pond, B.C. was the only jurisdiction in North America that allowed the importation of northern snakeheads. The province amended the controlled alien species regulation last December to ban all snakeheads and said a fine of up to $250,000 could be levied against anyone who released such a fish into local waters.
Jonathan Moore, a study co-author and assistant professor at SFU's School of Resource and Environmental Management, said the threat of snakehead introduction via illegal possession and trade still exists. He said snakehead introductions have continued in the U.S. despite the fact possession has been illegal for more than a decade.
The study said the Potomac River, in the eastern United States, could see up to a 35-per-cent reduction in largemouth bass due to the introduction of the northern snakehead.