April 1, 2021
Redfish biomass bonanza in the Gulf of St. Lawrence, we need a plan
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BY: Devan Archibald
Topics: Rebuild Ocean Abundance
Deep in the submarine canyons of the Laurentian Channel and in the Gulf of St. Lawrence redfish are having a “bonanza.” This term describes sudden good fortune and it has been used by the media to refer to a large growth in redfish populations. While the boom is good news, the story is more complex than the happy headlines may lead you to believe. This complexity is perhaps best exemplified by the fact that there are actually two species of redfish, Deepwater (Sebastes mentella) and Acadian (Sebastes fasciatus). These two species are nearly impossible to tell apart by looking at them and they are frequently lumped together when people talk about redfish, particularly in the commercial fishery. Additionally, managing this fishery is complex, it encompasses five provinces, four Fisheries and Oceans Canada (DFO) administrative regions, multiple municipalities and several First Nations communities. The current redfish biomass boom is an incredible opportunity for a re-emerging and expanded fishery but not if we don’t have a good plan to manage the complexities of the bonanza.
HISTORY: Redfish moratorium
A fishery for redfish began in the 1950s in the Gulf of St. Lawrence. Throughout the 1980s and early 1990s, landings averaged around 60,000 tonnes until they dropped precipitously. In 1995 a moratorium on fishing was put in place in the Gulf of St. Lawrence. The fishery remained open further out in the Laurentian Channel but landings continued to decline to low levels. The abundance of both redfish species dropped so low that in 2010 the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designated the population of Acadian redfish in the area as Threatened and Deepwater redfish as Endangered. Then something unexpected happened, from 2011 to 2013 the conditions in the Gulf of St. Lawrence favoured redfish larval survival and they began to come back.
There was an explosion of juveniles larger than anything seen before, particularly for the Deepwater redfish. By 2019 this abundance of juveniles had grown to the point where the biomass (weight of all the individuals of both redfish species combined) was huge. Redfish accounted for an incredible 90 per cent of the total biomass of everything caught in the region by DFO during their annual survey of marine life, compared to 15 per cent between 1995 and 2012.
PRESENT: New challenges
This abundance of redfish is one of several changes happening in the Gulf of St. Lawrence combined with shifts in temperature and oxygen. In recent years, there has been higher water temperatures and lower oxygen levels, particularly in deeper areas, breaking temperature records spanning over a hundred years. These unprecedented changes make sustainably managing human activities, including a re-emerging redfish fishery, complex but all the more important.
In 2021, DFO started consultations about what a redfish fishery could look like once the 1995 moratorium is lifted. Currently, the recommendation is to maintain the quota for the coming season. This is good, because there is still a lot of research and planning to do before we can expand the fishery.
FUTURE: Management plans
To manage the current and potential future abundance of redfish, DFO needs to be investing in a robust plan and keep fishing pressure low until we have one. This plan must be able to monitor and decrease the fishery’s negative impacts on other fish populations. Impacts such as bycatch, or the catch of non-target species, of the less abundant Acadian redfish, depleted Atlantic cod and white hake as well as commercially valuable Greenland and Atlantic halibut. The plan must also protect sensitive benthic, seafloor, habitats that have historically been damaged by gear commonly used in this fishery such as bottom trawls. Additionally, fishery monitoring and the role of redfish in the larger ecosystem must be considered. DFO started an experimental fishery in 2018 for industry to research potential solutions to some of these challenges. Meanwhile DFO and academia continue to research using existing and newly collected data to inform a future sustainable redfish fishery. There have been promising initial results, but more research is needed and the findings must be used to inform how this population is managed.
Focusing today on conducting research and developing a strong management plan will allow more time for the population to continue to mature. Although the Deepwater redfish population is now classified by DFO as healthy, most (51 per cent) of the fish born in 2011 are just now starting to mature. Fish populations do best when there are a variety of ages, and the age-structure is just starting to rebuild. This also means there are still a lot of small redfish in the water, including lots below the legal-size limit. Although there is industry pressure to harvest redfish now, the current population is still too small for higher value food markets. These small redfish are more valuable if left in the water to mature and breed rather than being fished for bait or fishmeal.
Managing redfish in ways that prioritize the populations long-term abundance will set this fishery up for success, so that this fish can once again help feed people and support coastal communities. Only then can we truly call it a bonanza, or good fortune, for all.
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