Shark researchers question DFO policy on catch-and-kill derbies
Some researchers support moving to catch-and-release tournaments
The catching of a large female mako shark has prompted some researchers to question the Fisheries and Oceans Canada policy on Nova Scotia's annual shark derbies.
The shark derbies are annual community festivals that include a shark-fishing event. Fishermen compete to catch large sharks, which are then turned over to the Department of Fisheries and Oceans so scientists can gather biological data. Sharks smaller than 2.4 metres are tagged and released.
Brendal Townsend, a shark researcher at Dalhousie University, says she is concerned that the data collected is no longer scientifically useful. She believes the same information could be gathered through catch-and-release methods.
Just because you're collecting data that doesn't make it science.- Brendal Townsend, Dalhousie University
"They say that they're collecting data. But just because you're collecting data that doesn't make it science ... If they're justifying the catching and killing of these animals, that information needs to be available to the public, not just in internal documents at DFO," Townsend said.
"I think there's a real opportunity here to move this event to catch and release. To make sure that there's more of an education component outreach here, on all the sharks that exist in Atlantic Canadian waters."
Published within DFO
Warren Joyce, a shark technician at DFO, said the information from the derbies does get published within the department.
"They are usually published in internal documents called research documents," he said.
"We haven't got around to mako sharks at the moment, but two years ago we had published a research document incorporating the data from the shark derbies in regards to the blue sharks.
"What we found in there was the overall mortality of the sharks landed in the shark derbies was about less than three per cent of the total population mortality. So it's a very small number in terms of what's actually caught commercially."
In recent years, derbies have caught about 100 or fewer sharks each year. However, Townsend says she is worried about the optics of killing a large shark and displaying it as a prize.
"We're catching and killing sharks and hanging them up for display for the general public. And that is an optical issue," she said.
"I think that's something that needs to be considered. Because sharks are not out there to eat people. They're not out there roaming the seas to get the next beach-goer. They're actually very fragile creatures, and very important for the ecosystem."
Largest sharks killed
Christine Ward-Paige, who teaches and studies sharks at Dalhousie, is also concerned about the derbies. She noted that the largest sharks are the ones that are killed.
"In Australia, one of the most well-managed shark fisheries in the world, they have imposed maximum size limits for shark fishing," Ward-Paige wrote in an email.
"They protect those largest sharks that are reproducing adults. This highlights the difference here, where Nova Scotia derbies kill only the biggest individuals."
Conservation groups trying to educate
Conservation groups like the World Wildlife Fund have been trying to do more education on how to identify and handle the sharks, says Jarrett Corke, a shark specialist with the organization.
"World Wildlife Fund has been engaged with the shark derbies for the last four to five years now, providing them educational materials on identification and the best catch, handle and release practices," he said.
"So the fishermen who are out on the water catching the undersized sharks — the ones that are being let go during the tournament — that those are being put back in the best condition possible."
Corke said the WWF has also been working more widely among fishermen to talk about shark handling. He said it was important to note that the recently-caught mako was estimated to be about 20 years old and sexually mature. He said killing large female sharks could have "unintended consequences" on that species.
Catch and release?
Joyce said the derbies are reviewed each year. He did not rule out the possibility of moving to catch and release, but said how the derbies are handled is between DFO management and the organizers, which is distinct from DFO's science branch. He noted DFO scientists continue to get valuable biological data from the derbies through methods like the voluntary tagging program.
He said the capture of the large female mako will provide more data, and DFO has only had one previous opportunity to study a female mako.
"I actually do have the reproductive tract out of it that we're hoping to look at," he said. "It'll give us more biological information on these large females."