Holistic assessment needed
Prospective reopening of redfish fishery and avoiding another debacle like northern cod
The prospect of re-opening the Atlantic redfish fishery later this year after a 30-year closure, sadly reminds me of the mismanagement of the northern cod stock.
While they are different in that one involves a possible reopening (redfish) and the other (northern cod) has never recovered enough to justify a full reopening, the uncertainties and controversies surrounding the scientific basis of the assessments and events leading up to management decision-making for both fisheries are similar.
DÉJÀ VU ALL OVER AGAIN
The rationale for reopening of the Atlantic redfish fishery is a pulse in biomass of commercial size redfish in the Gulf of St. Lawrence and on the Scotian Shelf, which has been observed in DFO research surveys and during an experimental fishery conducted by commercial fishers since 2018.
With the prospect of a future fishing bonanza, there has been intense pressure from commercial fishing interests, provincial governments, business, labour organizations and needless to say, politicians (in this case by all four Atlantic provinces and Quebec) for the reopening and to receive their “fair share” of the total allowable catch.
All this seems like déjà vu all over again as the saying goes. As we all remember too well, the directed fishery for northern cod was also closed 30 years ago due to overfishing. It has never recovered to historic abundance levels to this day.
UNCERTAINTIES IN BIOLOGICAL ASPECTS
We know less about the biology and ecology of redfish species than we do about the well-studied northern cod stock. Based on centuries of detailed catch data, DFO knew that the fishery could take 100-200 MT of northern cod without damaging the stock. Yet, the department ignored this fact and recklessly allowed the domestic fishery to fish for hundreds of MT more than that.
There are four species (and multiple sub-species) of redfish in the Northwest Atlantic, but two species, the Acadian redfish and deepwater redfish, are the most abundant and therefore will be the intended focus of the prospective fishery. Having said that, redfish species are difficult to discriminate with the naked eye, even by experts.
Redfish are highly vulnerable to fishing and slow to recover when depleted because they are long-lived, slow-growing, late-maturing and tend to produce large year classes episodically. There is little information for most times of the year on redfish diet, distribution and movements. Growth and age estimates vary widely. Little is known about the reproductive process. There is also a lack of understanding about why there is a different pattern of year class strengths between similar redfish species in the same areas.
BOTTOM TRAWLS AND FISH HABITAT
When the fishery was operational in the past, redfish were taken in gluttonous quantities by bottom otter trawls, a type of mobile fishing gear which was largely responsible for the demise of the northern cod stock.
Like cod, redfish aggregate in dense schools near the bottom during daylight hours, particularly when threatened or scared, making them highly vulnerable to this type of mobile fishing gear. Otter trawls are also known to do irreputable damage to fish habitat, particularly to sensitive attached organisms such as corals when their heavy steel rollers and foot ropes are dragged over the seafloor. Redfish are known to seek refuge in soft and stony corals.
The abundance and growth rate of redfish are found to be functions of coral habitat and thus deep-water corals can be considered an essential habitat for redfish.
UNCERTAINTIES IN STOCK STATUS
Even as excitement builds for the anticipated reopening of the redfish fishery, DFO reports that its latest stock size estimates are almost half of what they were only a few years ago. They say that there are not only fewer fish but that individual fish are physically smaller than they were when the fishery was last conducted.
Many are asking whether the fish are actually disappearing, shrinking or if variable stock size estimates are artifacts of sampling and assessment methodologies. If I had to choose, I know which one I would pick.
All of the above are cause for questioning the outputs of stock assessments and ultimately for sustainable fisheries management. Recently, the auditor general of Canada noted the inability of DFO to collect dependable and timely catch data as inputs to the assessment process for northern cod.
DELAYING OPENING BEST WAY FORWARD
Before a final decision is made, scientists should level with fisheries managers by telling them that there are too many scientific uncertainties to provide solid advice one way or the other on whether to reopen this fishery.
Conservation groups believe it is not worth the risk of damage it may cause to the environment and other high value or at-risk species like halibut and white hake. It may also not be worth it from an economic point of view since prices at the wharf for redfish are exceptionally low at this time.
DFO claims that it intends to adopt a cautious phased approach to opening the redfish fishery. At the very least, DFO should consider delaying the reopening for another year to give mature or maturing fish at least one more chance to spawn. This would also allow scientists to conduct additional research surveys to address knowledge gaps in the biology and distribution of redfish stocks. And it would allow time for them to conduct a holistic ecological-based assessment to complement or substitute for the single stock assessment currently used.
PROHIBIT USE OF BOTTOM TRAWLS
Delay or no delay, fisheries managers should ban the use of bottom otter trawls in any future fishery. Instead, they should restrict fishing to environmentally benign fishing gears such as baited hooks on long-lines or mid-water trawls.
Fisheries interests could also re-examine the marketing of redfish targeting the retail food sector. The fishery could be re-oriented to focus on providing bait for lobster and crab trap fisheries since traditional bait species such mackerel and herring are largely unavailable currently due to fisheries closures for those species. In the end, these measures could result in adding value to the fishery while at the same time protecting the resource.
Will DFO apply lessons learned in mismanaging the northern cod stock to the prospective redfish fishery? Time will tell.
Let us not jeopardize the sustainability of redfish stocks for expediency and economics. Let us learn from past mistakes, temper expectations, and proceed cautiously.