Canada’s Bluefin Tuna Live-Release Project First in the World

Canada continues its tradition of innovative research in the management of Atlantic bluefin tuna populations. 

In the first project of its kind, Fisheries and Oceans Canada (DFO), university researchers and tuna fishermen worked side-by-side in a controlled recreational “live-release” fishery to monitor the survival rate and behaviours of caught and released Atlantic bluefin tuna. 

“This research will put Canada in the forefront of developing responsible recreational fisheries by ensuring that incidental mortality associated with catch and release activities is explicitly accounted for in the management of the resource,” explained Faith Scattolon, Canadian Commissioner to the International Committee for the Conservation of Atlantic Tunas.

The team consisted of Dr. John Neilson with DFO Science, Dr. Michael Stokesbury of Acadia University and Pat O’Neill, a consultant with the Prince Edward Island Fishermen’s Association. With funding support from the Government of Canada and the PEI government, they devised a method using pop-up satellite archival tags (PSAT) to track the incidental mortality of tuna that have been released in the sport fishery.

Study will provide more accurate estimates of survival

A trial catch and release fishery was organized over a two-week period starting August 28, 2010 –– 59 tuna were captured using barbless circle hooks. Each fish was reeled in and once alongside a tagging boat, was fitted with a satellite tag before being released back into the Gulf of St. Lawrence. Twenty licensed tuna fishermen and charter boats from PEI participated in this part of the project.

Current estimates of 11 percent post-release mortality need to be refined to more accurately assess the impact of the recreational fishery. Dr. Neilson noted that “this study has garnered a great deal of interest, as the estimates of mortality will now be obtained from scientifically-controlled catch and release tagging operations.” 

Dr. Stokesbury, who led the scientific team on board the tagging vessel, explained that PSAT tags collect extensive data such as fish location and water temperature, depth, and salinity. They are then scheduled to release from the fish between April and October 2011. After the tags float to the water’s surface, they relay their stored information to a satellite. That information is then downloaded to a computer.

“The tags have pre-release software so we will know within a few days of tagging the fish if any died from the experience of capture and release,” he said. As well, if the tuna was injured by the capture, it would be evident in the behavioural information from the tag.

Dr. Steve Cooke from Carleton University also participated in the study. As an expert in the physiological effects of catch and release on many species of fish, he and one of his graduate students assessed the condition of each tuna after undergoing strenuous exertion and took biopsy samples at the time of tagging.

Canada’s existing recreational bluefin tuna fishery

In Canadian bluefin tuna fisheries, almost all fish are landed and sold as part of the regular commercial fishery. Currently, recreational fisheries are limited to several tournaments where fish are landed and sold as part of the commercial fishery quota, and a small-scale catch and release charter fishery in the southern Gulf of St. Lawrence. There are strict regulations that apply to the recreational bluefin tuna fisheries that include hook type and size, daily limits and daily log book entries.

Live-release fishery has great economic potential

The live-release bluefin tuna fishery in Canada has potential to become an increasingly marketable sport fishery and may have enormous economic potential in PEI and possibly other parts of Atlantic Canada.

A preliminary report on this live-release study will be available later in the fall of 2010 based on the information gained to that point. It is likely that the results will be specific to this particular fishery. According to Dr. Neilson, post release survival rates are expected to vary by location of a particular fishery. He cited the average size of the released fish and water temperature as examples of factors that may influence survival.

The results of this study will provide one more tool for Canada to sustainably manage its bluefin tuna fishery.