- Trawling vessels pursuing fish are damaging marine ecosystems in Canada’s West Coast waters and could be operating illegally in some cases, and yet they work with insufficient transparency, a new NGO report says.
- Nine large trawlers have together trawled swaths of the ocean collectively larger than the size of Ireland since 2009; they have likely trawled in prohibited zones at least 47 times and have disrupted Chinook salmon (Oncorhynchus tshawytscha) migratory routes, which are foraging areas for an endangered population of killer whales (Orcinus orca), the report says.
- A trawling industry group dismissed the NGO’s findings, saying they lacked context and the fishery was very well regulated.
- A Canadian regulatory agency said the fishery was well managed, with strict monitoring and enforcement of rules.
Trawling vessels pursuing fish are damaging marine ecosystems in Canada’s West Coast waters and could be operating illegally in some cases, and yet they work with insufficient transparency, a new report says.
Nine large trawlers have together trawled swaths of the ocean collectively larger than the size of Ireland since 2009, according to the report, and have likely trawled in prohibited zones at least 47 times. The report, which was released as an interactive story map by the Canada-based NGO Pacific Wild on June 24, deals with trawling in the waters of British Columbia, Canada’s westernmost province. It says that trawling pathways were “almost perfectly aligned” with Chinook salmon (Oncorhynchus tshawytscha) migratory routes, which are foraging areas for an endangered population of killer whales (Orcinus orca).
A trawling industry group dismissed the NGO’s findings, saying they lacked context and the fishery was very well regulated.
The Ireland-sized footprint includes both midwater and bottom trawling but is likely an underestimate, as Pacific Wild could not obtain complete data for the nine vessels. The figure also doesn’t include trawling conducted by the dozens of smaller vessels that have worked in the province’s waters during that time period. There were 41 trawling vessels active in 2023 and 28 in 2024, for example.
Canadian authorities haven’t released trawling footprint data since 2016 despite requests from Pacific Wild. The group purchased commercial automatic identification system (AIS) tracking data from two third-party companies to complete its investigation.
“The inspiration for this project was really the lack of transparency between the government and the public on exactly where our coast is being trawled, where fishing is taking place, because this trawl fishery primarily happens offshore, out of sight and largely out of mind for the general public,” Sydney Dixon, a marine specialist at Pacific Wild, told Mongabay.
The British Columbia trawlers target a wide variety of species, including Pacific hake (Merluccius productus) and Alaska pollock (Gadus chalcogrammus). Trawling is a relatively indiscriminate fishing practice targeted at both open-water or pelagic species in the case of midwater trawling, and seabed or benthic species in the case of bottom trawling, which is particularly controversial. Bottom trawling involves dragging heavily weighted nets along the seafloor, killing seabed lifeforms, destroying marine habitat and stirring up sediment. The U.S. Geological Survey, a government agency, has compared the practice to rototilling the seabed.
Marine conservation groups are making a global push to ban or limit trawling, mainly emphasizing bottom trawling, which provides roughly one-quarter of the live-caught seafood consumed globally. Pacific Wild itself is calling for a ban on both forms of trawling in British Columbia.
The NGO’s investigation, which took two years, found that trawlers “consistently target the most productive and ecologically important areas, such as continental shelf breaks, submarine canyons, and seamounts.” These it calls the “breadbaskets” of Canada’s coast, where marine animals feed, breed and, in the case of mammals, nurse their young.
The nine vessels, which vary in length from 29-58 meters (95-190 feet), engaged in likely trawling activity for more than 900,000 kilometers (more than 485,000 nautical miles or 560,000 miles) in British Columbia’s waters between 2009 and 2024, the report says. The width of a standard trawl net of a vessel in that size range is 90 meters (295 feet), and so Pacific Wild estimated that the nine vessels had trawled 89,700 km2 (34,626 mi2) — an area larger than Ireland. That figure includes vessel drags that overlap: Certain areas were hit repeatedly. Looked at from a bird’s-eye view, the nine vessels trawled 17,138 km2 (6,617 mi2), spatial ecologist Kevin Lester, who conducted the AIS analysis for Pacific Wild, told Mongabay.
Lester determined likely trawling activity from vessel speed and other factors available through the AIS data. He found 47 instances of likely trawling in prohibited sections of marine protected areas (MPAs) by the nine vessels. (Some older MPAs in British Columbia allow trawling.)
Lester cautioned that the evidence of illegal trawling is not definitive. “It highlights that we need to be looking at what they’re doing there,” he said. “It’s more of a call for transparency and a deeper look because I can’t say for certain that they had nets in the water at that time, but it’s strong evidence.”
It’s not possible to differentiate between midwater and bottom trawling from AIS data, and some of the vessels carry both types of gear. Pacific Wild received bycatch records from Fisheries and Oceans Canada (DFO), the national regulator, which showed that even the midwater trawlers have caught some benthic species such as sea stars. This suggests the nets, meant to be dragged through the water column, may actually be dragged along the bottom sometimes.
The bycatch records from DFO, which ran from 2013-23, also showed that the trawling nets had brought up Pacific white-sided dolphins (Lagenorhynchus obliquidens), seals, sea lions, endangered basking sharks (Cetorhinus maximus) and even a humpback whale (Megaptera novaeangliae) and a gray whale (Eschrichtius robustus), as well as hundreds of other marine species. About a quarter of the bycatch was juvenile Pacific hake, which at full maturity is a target species for trawlers. Most bycatch globally dies, including in trawl fisheries. Recent government research had already shown that the trawlers took heavy Chinook salmon bycatch, which the Pacific Wild report said can be explained, in light of the new findings, by the fish having to “run the gauntlet” though a concentrated area of trawling. The salmon are of special importance to Indigenous communities and are the primary food source for southern resident killer whales, an endangered population.
Zoe Ahnert, executive manager of the Deep Sea Trawlers Association of British Columbia, an industry group that represents some of the companies that own the nine vessels, said the report failed to give an accurate depiction of trawling in the province.
“We urge that any dialogue about this fishery be rooted in the full scientific and regulatory context rather than selective interpretations of limited data,” she said in an email.
Ahnert said the “B.C. groundfish trawl fishery is one of the most transparent, accountable, and sustainably managed fisheries in the world” and supports more than 1,100 jobs.
Pacific Wild contends there is insufficient transparency in Canada regarding the footprint of fishing vessels and on other fisheries matters. DFO in the past released some aggregated trawling footprint data for the years 1997 through 2016 but hasn’t done so for subsequent years. Vessels’ compliance with at-sea rules is now tracked entirely via electronic monitoring — by onboard video and sensors, as well as by GPS — and the footage and other data aren’t public, either, Dixon said. The DFO is restricted in what it can share because of laws deeming such information proprietary, as in other countries.
DFO also doesn’t release data on beneficial ownership showing the entity that ultimately owns a vessel and profits from its activities, which one academic expert called a “disgrace” in a brief to a Canadian government body in 2023. In this case, Ahnert said the companies that own the nine vessels were Canadian-owned and the beneficial owners were Canadian.
Dixon said DFO was “beholden to privacy laws” and she understood that “they have to play within the rules that they’re given” but the lack of transparency is a major problem.
Jennifer Young, communications adviser at DFO, told Mongabay in an emailed statement that “the B.C. groundfish trawl fishery operates under strict monitoring and conservation measures to protect sensitive marine habitats and ensure sustainable fishing practices.”
A published management plan “outlines where and when trawl fishing can occur,” Young said, noting that bottom trawling is particularly restricted. Management is “complemented by rigorous catch audit and enforcement procedures,” she said, pointing to a 2024 case in which a fishing company was fined for fishing illegally in an MPA. (The case dealt with a type of bottom fishing in which a weighted line with baited hooks sits on the seabed, not trawling.)Young also noted that ownership information for some vessels appears on the vessel search portal on DFO’s website. However, Dixon said transparency is still a challenge because beneficial ownership often remains unclear, and some of the vessels are owned by companies that put out no public-facing information.
Dixon argued that in spite of the money made from the fishery, trawling had to be ended.
“In a time when there’s a biodiversity crisis, there’s a climate crisis, we really should be taking every precautionary measure that we can to save what we have left, rather than sticking with the status quo that we know is damaging,” she said.
Banner image: Chinook salmon (Oncorhynchus tshawytscha). Image courtesy of Eiko Jones.
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