Trawl vessels in British Columbia use large nets to target groundfish like pollock and hake, the same species often turned into products like imitation crab or fish sticks. But these nets don’t just catch what they’re aiming for. They can also capture a wide range of other marine life, from seals to salmon. These unintended catches, known as bycatch, haven’t always been consistently or accurately monitored. For some species, particularly salmon, this means past bycatch levels may have been underreported or not fully captured, due to gaps in tracking, observer coverage, and reporting systems that have only improved in more recent years.
The introduction of an enhanced monitoring program for salmon bycatch in the British Columbia (B.C.) groundfish trawl fishery in the 2022/2023 fishing season marked an important step forward for transparency and accountability. This monitoring uncovered a staggering amount of salmon bycatch, leading to the establishment of a Chinook salmon bycatch cap by Fisheries and Oceans Canada (DFO) in the 2024/2025 fishing season. The Chinook bycatch cap is a meaningful conservation milestone. It reflects a growing recognition that salmon mortality in mixed fisheries, those that target multiple species rather than a single stock, must be actively constrained, not treated as an inevitable byproduct of harvest.
We welcome that progress. A cap of 9,000 Chinook salmon per fishing season signals that salmon are being treated as a finite and valued resource. It provides a necessary foundation for more precautionary, ecosystem-based management.
At the same time, recent data shows that what’s happening in this fishery isn’t just about regulations. Fishing effort, the amount of time and activity spent fishing, including how many boats are operating and how often, has changed substantially. Those shifts are closely linked to the drop now seen in salmon bycatch.
A Significant Decline in Salmon Bycatch
Total salmon bycatch in the groundfish trawl fishery has dropped sharply over the past three fishing seasons:
- 2022/2023: 28,183 salmon
- 2023/2024: 28,145 salmon
- 2024/2025: 7,527 salmon
This represents an approximate 73% reduction between the first year that enhanced monitoring began in 2022/23 and 2024/25.
For Chinook salmon specifically:
- 2022/2023: 26,273 Chinook
- 2023/2024: 21,696 Chinook
- 2024/2025: 7,040 Chinook
Over these three years, there has been a 73% reduction in chinook salmon bycatch, with most of the decline occurring in the most recent fishing year. These are substantial changes that matter for conservation.
The key question, however, is: what is driving this reduction?
Fishing Effort Has Declined Sharply
Midwater trawl effort shows a clear and concurrent decline:
- 2022/2023: 3,424 midwater tows
- 2023/2024: 3,012 midwater tows
- 2024/2025: 1,682 midwater tows
This represents an average reduction of roughly 47.5%, with the steepest drop in the most recent fishing season. Chinook bycatch declines closely track these reductions, indicating a strong relationship: as effort decreases, bycatch decreases in near proportion.
While the dataset is limited to three annual observations and cannot support robust statistical inference, the directional signal is clear: fishing effort is likely a dominant driver of salmon bycatch in this fishery.
Gear Type and Where Bycatch Occurs
Across all three fishing seasons, midwater trawl gear remains the primary source of salmon bycatch. In the 2022/23 fishing season, approximately 96% of salmon bycatch occurred in midwater operations, reinforcing evidence that this gear type carries a higher risk of salmon encounters than bottom trawls. Bottom trawl effort has remained relatively stable (around 5,200–5,400 tows), yet bycatch remains concentrated in midwater activity. This suggests that targeted reductions in specific fishing practices can yield disproportionate conservation benefits.
Bottom Trawl
Midwater Trawl
Fleet Composition Is Shifting
Structural changes in the fleet also help explain shifting bycatch patterns. In earlier seasons, freezer vessels accounted for roughly 70–74% of salmon bycatch. In the 2024/25 fishing season:
- Fresh (wet) vessels: ~58% of Chinook bycatch
- Freezer vessels: ~42%
This shift appears to be driven in part by fewer freezer vessels participating, along with broader changes in fishing effort. The makeup of the fleet matters because it shapes where, when, and how fishing happens, and therefore how likely vessels are to encounter salmon. Wet vessels generally operate closer to shore, while freezer vessels can remain at sea for weeks and fish farther offshore. With freezer vessels making up a smaller share of the trawl fleet in recent seasons compared to 2022/2023, it follows that fewer salmon may be intercepted along their offshore migration routes.
The Relationship Between Effort and Bycatch
A consistent pattern emerges: as fishing effort declines, salmon bycatch declines.
- Midwater trawl effort ↓
- Salmon bycatch ↓
- Chinook bycatch ↓
Although the dataset is limited, the alignment between effort and bycatch is difficult to ignore. The data provides a strong directional signal, even if they do not yet support a definitive long-term model.
Recognizing Progress, Clarifying Drivers
The introduction of a Chinook bycatch cap is an important step toward more accountable fisheries management, and that progress should be recognized. However, recent reductions in bycatch appear closely tied to decreased fishing effort, particularly in midwater trawl activity. This distinction matters. In recent years, one of the fishery’s primary target species, Pacific hake, has been largely absent from B.C. waters, with vessels reporting difficulty finding fish. As a result, quota attainment has dropped sharply (to just 2.7% in 2024), landings have reached historic lows, and many vessels have stayed in port altogether. These conditions help explain the decline in fishing effort and, in turn, the reduction in bycatch.
At the same time, it remains unclear how much of this trend is driven by environmental variability versus longer-term changes in the fishery. If bycatch reductions are mainly the result of reduced effort rather than structural management changes, their durability will depend on whether effort remains low. Without continued attention to fishing intensity, bycatch could rise again under the same framework if target species return and fishing activity increases.
What Comes Next: Strengthening Conservation Outcomes
The data points to several priorities for the next phase of management, each of which warrants deeper attention and practical implementation.
- Strengthen real-time monitoring and transparency.
This means going beyond current requirements to ensure that bycatch is tracked, verified, and publicly reported in near real time. Options could include expanding enhanced monitoring programs to monitor bycatch of other ecologically important species, re-instating the use of independent on-board observers, and improving electronic monitoring systems (such as cameras) with clear standards for review and accountability, including public access to this footage for independent review. Making summarized data publicly accessible in a timely way would also help build trust and enable independent analysis. - Ensure bycatch caps remain precautionary.
A precautionary cap is one that is set low enough to prevent harm even under uncertainty. In practice, this means regularly reviewing caps in light of updated stock assessments, climate variability, and cumulative impacts on salmon populations. Caps should not simply reflect what is currently achievable under low fishing effort, but instead what is biologically safe if effort increases again. - Improve gear selectivity and avoidance strategies in midwater trawl fisheries.
Reducing bycatch at the source requires making fishing practices more selective. Midwater trawl gear is known to capture a wide range of species depending on mesh size, net design, and fishing practices. Modifications such as bycatch reduction devices (BRDs), changes in mesh size, and escape panels have been shown to allow non-target species to exit nets while retaining target catch. For example, studies of trawl gear modifications, including sorting grids and escape panels, demonstrate that these designs enable larger or non-target species to escape while maintaining high retention of target species . Similarly, experimental work on salmon excluder devices in pelagic trawls shows that appropriately designed escape openings can achieve high escapement rates for non-target species like salmon. In addition to gear improvements, fleets can adopt avoidance strategies, such as using real-time data to steer clear of areas with high salmon presence, or adjusting fishing depth and timing to reduce overlap with migrating fish. - Evaluate spatial and temporal measures to reduce salmon encounters.
In practice, this means identifying when and where salmon are most at risk, such as along migration routes or during peak migration periods, and applying targeted management tools. These could include time-area closures, rolling closures triggered by bycatch thresholds, or dynamic management zones that shift in response to real-time data. These approaches can be used in fisheries management to reduce interactions between fishing activity and sensitive species. For instance, time-area closures and dynamic management measures are commonly applied to limit bycatch risk by restricting fishing in areas or periods of high species vulnerability, particularly in trawl fisheries where bycatch risk is otherwise high . Such strategies are a standard component of modern fisheries management frameworks aimed at reducing unintended catch and improving sustainability. - Separate the effects of reduced effort from true changes in encounter rates.
It is critical to distinguish whether declining bycatch reflects fewer interactions between fish and fishing gear, or simply less fishing overall. This requires analyzing bycatch relative to effort (e.g., bycatch per unit effort) and continuing to track trends as fishing activity changes. Without this distinction, it is difficult to assess whether current management measures are genuinely effective or whether improvements may reverse as effort increases.
More broadly, many jurisdictions around the world are moving toward banning trawling altogether. Ultimately, that is the direction Pacific Wild supports, given that indiscriminate fishing methods are inherently problematic. In the interim, however, there are still important steps that can be taken to reduce harm.
The immediate goal should be to lower the likelihood of salmon interactions, not just to cap total mortality. The enhanced monitoring program and Chinook bycatch cap represent meaningful progress, reflecting a system that is increasingly willing to measure and manage its impacts. At the same time, the data underscore a simple point: effort matters.
Declines in salmon bycatch closely track reductions in fishing effort, particularly in midwater trawling. This is both encouraging and instructive. It demonstrates what is possible when pressure is reduced, but also highlights how strongly outcomes depend on fishing intensity.
The challenge now is to ensure these gains are durable and intentional, rather than incidental results of fluctuating effort. Long-term success will depend on building a system in which reduced bycatch is embedded in how the fishery operates, not left to chance.
Expanding the Lens: Protecting Pacific Herring
Recent global research highlights an important limitation in how bycatch is understood, with direct relevance to the B.C. groundfish trawl fishery. A study by Foster et al. (2026) found that what gets recorded as “catch” doesn’t always reflect what’s actually happening in the water, in part because different species are inconsistently identified and reported. In other words, gaps in reporting can shape the data just as much as fishing activity itself.
Looking across thousands of records, the study found that about 95% of species that were identified in trawl catches were classified as bycatch rather than targeted species. Put simply, this means trawl fisheries tend to catch a wide variety of marine life incidentally, not just the species they’re aiming for. This finding reinforces how broadly trawl gear can interact with ocean ecosystems, and why improving monitoring and reporting is critical for understanding and managing those impacts.
The study also finds that smaller-bodied fish, like forage fish, are systematically underrepresented in catch records. These species are often grouped into broad categories and not individually identified by species, meaning current datasets likely underestimate both species diversity and total ecological impact of trawl fishing. Foster et al. argue for improved species-level monitoring, more complete record-keeping, and precautionary management tools, including spatial and temporal protections in line with the recommendations made in the section above.
Connecting These Findings to the B.C. Context
Similar patterns appear in B.C.’s bycatch data, particularly for Pacific herring. Records distinguish between “Pacific herring” and a broader “Herrings” category that aggregates multiple species, including Pacific herring, sardines, pilchards, sprats, shads, anchovies and more.
In 2022, midwater trawl bycatch records reported:
- 271,616.28 kg as “Pacific Herring”
- 230,816.07 kg as “Herrings”
Because the broader category likely includes Pacific herring, the species-specific total is almost certainly underestimated. This mirrors the patterns identified by Foster et al., where limited taxonomic resolution obscures the true scale of impacts. When species are grouped or inconsistently identified, it becomes difficult to assess and understand ecosystem effects, or design effective management measures. Part of the fishery’s ecological footprint remains hidden.
A Call to Action: Extending Monitoring to Pacific Herring
The progress made on salmon monitoring shows what is possible when a species is treated as ecologically and culturally significant. The same recognition is warranted for Pacific herring.
Pacific herring are foundational to B.C.’s coastal ecosystems, supporting marine food webs, Indigenous food systems, and coastal economies. They provide the nutrient bridge between plankton and larger predators in the food chain, like salmon, people and humpback whales. Yet current reporting likely does not consistently capture their true level of interaction with the groundfish trawl fishery.
An enhanced monitoring program for Pacific herring, similar to what has been implemented for salmon, would be a critical next step.
If management is to remain within ecological limits, it must account for what is being removed from the ocean, not just what is easiest to measure. Biodiversity cannot be treated as incidental. Just as the Chinook bycatch cap represents a shift toward accountability for salmon, a similar commitment is needed for Pacific herring. Without it, we risk underestimating impacts on a key species, and missing an opportunity to build a more complete and resilient approach to fisheries management.
