A new study based on satellite tagging and interviews with fish harvesters has revealed a potentially negative impact between halibut spawning grounds and a potential redfish fishery in the Gulf of St. Lawrence.
According to researcher Rachel Marshall of the Fisheries and Marine Institute, the study started as a tagging study on halibut off the west coast of Newfoundland and Labrador in Northwest Atlantic Fisheries Organization (NAFO) division 4R. The goal was to work with fish harvesters’ anecdotal evidence along with tagging to track halibut spawning and migration in the area.
“That tagging study went really well and so we were able to keep going and deploy more tags at a broader spectrum. We put them around the Gulf instead of just Newfoundland and once we started getting results, then we would present them to the halibut harvesters,” said Marshall.
While presenting their findings to harvesters on the west coast of N.L., Marshall conducted interviews with harvesters. During the interviews, harvesters commented on the increased abundance of halibut in the Gulf. It was during this round of interviews that the researchers heard about the redfish fishery.
“We had been primarily focused on the tag data and the halibut behaviour, but when we presented it to the halibut harvesters, they immediately put into that context that it was relevant to them and the other industry,” said Marshall.
Redfish in the Gulf of St. Lawrence, much like cod, are groundfish that were subject to overfishing in the mid-1990s. Due to their population collapse, the commercial fishery has been closed ever since. Nowadays, redfish have made an astounding comeback and many are waiting for the moratorium to be lifted on this now abundant stock.
This recent study, however, raises more questions about the unintended results of trawling for redfish should a new fishery be opened. Notably, the area they seem to be most prominent is also the presumed spawning grounds of Atlantic halibut.
“[The harvesters] know the redfish population has gotten pretty big and so they know there’s this possibility that they’ll open a new one,” said Marshall.
“What they were telling us is that’s a trawl fishery and so you’re showing us that the spawning habitat is right here and that’s where the trawl fishery is going to go. I asked them why the halibut population was so big now and they said, ‘Oh, it’s because they cut out trawling in the past.’ So, the halibut were no longer being by-catched in these trawl fisheries.”
Along with redfish, the Atlantic halibut population has also been classified as a threatened species, being labelled “endangered” in 1996 by the International Union for Conservation of Nature (IUCN). The population is now considered “near threatened,” but the population is slow growing, as they achieve sexual maturity at a later age than some fish stocks.
“When they say the population is going up, this is because the fish harvesters say their landings are easier to catch in a shorter amount of time, or with less gear,” said Marshall. “You can see the quotas are going up, but the catch is meeting all those quotas.”
To fully assess the feasibility of a sustainable redfish fishery and for other fisheries studies in general, Marshall and her colleagues believe more conversation needs to be had with fish harvesters. The practical knowledge of those that work at sea, she says, is important for giving context to scientific data collected.
“Combining the two types of data — the traditional scientific data, which would be our electronic tagging data, with the fish harvesters’ ecological and historical knowledge — making that combination is really important for putting the science into these broader contexts,” said Marshall.
“Incorporating the fish harvesters from the beginning, so we make sure that we’re answering questions that are actually relevant to them, and then making sure to keep them informed throughout the process so that we’re constantly hearing their response to what we’re doing so we can make adjustments so the science is doing the most that it can do.”
