Columbia River Pound Nets Move Forward as an Alternative Model for Sustainable Salmon Fishing

By Adrian Tuohy

Any craftsman will tell you to use the right tool for the job, or you may do more harm than good. The same adage applies to fisheries management and the tools we use for commercial fishing. Across the North American West Coast, mixed-stock harvesting, fisheries bycatch, and unsustainable hatchery practices harm the recovery of wild Pacific salmonid (Oncorhynchus Spp.) populations listed under the U.S. Endangered Species Act (ESA) and Canada’s Species at Risk Act (SARA). Mostly to the detriment of wild salmonid population genetics and ecosystems, millions of hatchery fish are produced annually from federal, state, and tribal hatcheries to increase short-term harvest opportunities for industry. However, absent use of in-river fishing tools that can selectively harvest hatchery fishes (and/or other healthy and abundant stocks) while releasing threatened wild salmonids unharmed, neither hatcheries nor salmon fisheries can be managed effectively to achieve conservation or harvest objectives.

Mixed-stock salmon fisheries with non-selective fishing gears (e.g., troll, seine, and gillnet) occur in waters across the North American West Coast, affecting wild salmon populations as they feed in marine waters far from home, and as they migrate to natal rivers and streams in efforts to reach the spawning grounds. The effects of mixed-stock harvesting are most indiscriminate and potentially damaging when fisheries occur farther from rivers of salmon origin. In ocean fisheries of the North Pacific where salmon from watersheds up and down the West Coast co-mingle, fishermen have little to no means of determining the health of the stocks they are harvesting. For example, genetic evidence from the Pacific Salmon Commission suggests that up to 97% of the target species harvested in the southeast Alaska troll fishery for Chinook salmon (O. tshawytscha) represent potentially threatened stocks from rivers of British Columbia, Washington, and Oregon (of which ~50% originate from the Columbia River). Across the West Coast, indiscriminate ocean fisheries such as this damaging troll fishery cause mortality of wild salmon listed under the ESA and SARA, preventing orca whales (Orcinus orca) from securing the food they need for survival and diminishing salmon returns to the rivers our local communities have invested so much to protect and restore. Adding insult to injury, fishes harvested in these mixed-stock fisheries are often labeled as ‘sustainable’ by Marine Stewardship Council, providing price advantages and further incentive for fishers to maintain and advocate expansion of unsustainable fishing practices via troll, seine, and gillnet in the ocean.

For the fish that survive the gauntlet of unsustainable ocean fisheries, the mixed-stock fishery problem persists within their home rivers as they seek access to upriver spawning grounds. In the Columbia River, mixed-stock harvesting—compounded by hatchery production— contributed to the decline and extirpation of many of our wild salmonid populations. Although efforts have been made to reform both harvest and hatchery management, it is evident that these same management factors continue to compromise the recovery of wild salmonids. For example, the proportion of hatchery-origin spawners consistently, and often dramatically, exceeds biological thresholds necessary to protecting wild salmonid population

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The Osprey productivity and fitness throughout the watershed. Furthermore, mixed-stock harvesting with gillnets continues to impact ESA-listed wild fishes and severely constrain fishing opportunities to remove marked hatchery salmon that have been produced for the purpose of increasing short-term harvest opportunities. Clearly, management goals for wild salmonid conservation, harvest reform, and hatchery reform are not being achieved through the existing salmon management paradigm and not one of thirteen ESA-listed salmonid populations groups have recovered in the Columbia River.

Beginning in 2016, Wild Fish Conservancy (WFC) initiated a project in the lower Columbia River to develop an alternative model for sustainable salmon fishing. We were inspired by successes in the Salish Sea and rivers of British Columbia where commercial and First Nation fishers had returned to promising fixed-gears such as reef nets and fish wheels for selective harvesting. Recognizing that salmon fisheries are most sustainable when operating in or near rivers of salmon origin with lowimpact, passive fishing tools, we revitalized the pound net (often referred to as a ‘fish trap’) as a means for passive capture, live-sorting, and the release of wild salmonids within the lower Columbia River (an environment that is unsuitable for use of either reef nets or fish wheels due to tidal conditions, turbidity, and river flows). Too often, resistance to change in Washington and Oregon came from industry and management that claimed no other alternative method of fishing existed or was viable to replace status-quo mixedstock fisheries via troll, seine, and gillnet. In 2016, we teamed up with local commercial fishers to challenge this assumption and build a model of sustainability for replication elsewhere.

To identify a solution to the mixedstock fishery and hatchery management problem, commercial pound nets were retooled, implemented, and tested in the lower Columbia River to evaluate how a transition toward this in-river fishing method could allow fishers to selectively harvest hatchery produced fish with minimal mortality of co-mingling wild salmonids. Tagging studies conducted in 2017 for the original pound net prototype demonstrated that the fishing method could be used effectively to capture targeted hatchery produced Chinook salmon and coho salmon

Hand-colored photograph of a fish wheel on the upper Columbia River, circa 1910. Fish wheels, owned mainly by cannery companies, were used to harvest salmon on the Columbia River from 1879 to 1934, when they were banned due to political pressure from downriver commercial fishers and sport anglers who viewed them as unfair competition, and Native tribes for infringing on traditional indigenous fishing sites. Photo Courtesy US Forest Service

(O. kisutch) while releasing wild salmonids unharmed. Using a paired control-treatment tagging study design, our 2019 publication in the journal of Fisheries showed survival of summer steelhead (O. mykiss) and wild fall Chinook salmon bycatch ranging from 94.4% to 99.5% over a 2-week, 400 km upriver migration post-release from the fishing gear. In 2019, further research of a modified passive capture procedure with the pound net (published in the North American Journal of Fisheries Management in 2020) proved effective in achieving nearly 100% survival of sockeye salmon (O. nerka) bycatch through yet another controltreatment tagging study. These findings suggested that pound nets could be used effectively to improve the precision of commercial harvesting; hatchery fishes of a specific river could be selectively harvested to reduce the proportion of hatchery-origin spawners while wild salmonids could be effectively released to resume the spawning migration.

Building upon this promising research, our most recent publication in the journal Fisheries Research (“Maximizing

Salmonid Bycatch Survival with Passively Operated Commercial Fish Traps”) has provided the most simple and persuasive evidence to date that pound nets may be highly effective at reducing bycatch mortality and providing a means for resource managers to reduce straying of hatchery fishes within the lower Columbia River (for more information, view https://doi.org/10.1016/j.fishres.2022.106 495). Between 2019 and 2021, additional survival studies for adult coho salmon,

Continued on next page spring-run Chinook, and summer-run Chinook salmon were conducted at two separate pound net sites in the lower Columbia River. Over three years of study, mark-recapture tagging and net pen holding methodologies were used to estimate survival of Chinook salmon and coho salmon, respectively. Evaluating detections of Chinook salmon tagged and released from a passively operated pound net in 2019, detection of tagged fish at Bonneville Dam over a mean 6.5 d upriver migration (167 km) was 1.000 (95% CI: S ≥ 0.970) for the sample genetically assigned to populations originating upriver of Bonneville Dam (100% detection and survival after erated pound nets may allow for selective harvesting of targeted fish stocks with little to no mortality of adult salmonid bycatch in the lower Columbia River and other low-gradient, lowturbidity rivers that may be compatible with the gear-type.

Given the success of the research over the past decade in the Columbia River and strong support from science and conservation communities, the Washington Department of Fish & Wildlife (WDFW) recently completed a lengthy rulemaking process that will legalize use of pound nets for selective harvesting in the lower river by the 2024 fishing season (WAC 220-360-500).

For the first time in 90 years, commercial use of pound nets will return to wa- release from the fishing gear). Through two separate net pen holding studies where fish were released into captivity for observation after capture and release from the fishing gear, survival of coho salmon was 1.000 (95% CI: S ≥ 0.975) over 4 d in 2020 and 0.965 (95% CI: 0.948 ≤ S ≤ 0.969) over 6 d in 2021 (100% and 96.5% survival, respectively). Given that these analyses lacked control groups to adjust survival estimates for confounding mortality effects (e.g., marine mammal predation, research handling/tagging effects, etc.), study results were inherently conservative from this Fisheries Research publication. Ultimately, these findings support the conclusions of prior studies and further suggest that passively op- ters of the Columbia River as an alternative to gillnetting. This time around, contemporary pound nets will serve as a means to protect wild salmonid bycatch, reduce straying of hatchery fish to wild salmon spawning grounds, improve compliance of state hatchery programs with ESA requirements, and provide sustainable fishing opportunities for commercial and tribal fishing communities. If implemented as anticipated, the emerging commercial pound net fishery could prove to be a model of sustainability within our region, helping fishers maintain their fishing tradition while advancing salmon management and recovery throughout the Columbia River Watershed.

Although the lower Columbia River commercial fishery represents just a small-piece of the wild salmon recovery puzzle, a successful working model for selective commercial fishing in the Columbia could help drive a much broader transition toward the sustainable salmon management practice of harvesting in or near rivers of salmon origin with suite of low-impact, passive fishing tools that may be compatible with a given fishing environment (e.g., pound nets for river reaches with lowvelocity and low-turbidity; modified fish wheels for rivers with high-velocity and high-turbidity; and reef nets near river mouths in the Salish Sea). Paired with the recent court victory against the National Marine Fisheries Service over their approval of the mixed-stock southeast Alaska troll fishery for Chinook salmon, it is our hope that the emerging Columbia River pound net fishery may demonstrate that transition to this alternative model of sustainable salmon fishing is achievable and advantageous to wild salmon recovery, orca whale recovery, and our region’s fishing economies. As the viability of in-river selective fisheries is demonstrated on a commercial-scale and communities across the coast continue to raise their voices in opposition to the approval of unsustainable mixedstock ocean fisheries occurring from California to Alaska, there is hope that our collective conservation efforts may redirect salmon management and industry toward a more sustainable path that protects the needs of wild fish, fishermen, and future generations.

Adrian Tuohy is an aquatic and fisheries biologist with the Wild Fish Conservancy. He currently leads projects developing and researching sustainable commercial fishing practices in Oregon, Washington and British Columbia. To learn more about the Wild Fish Conservancy Northwest visit: https://wildfishconservancy.org

For additional information about the Wild Fish Conservancy’s pound net project, see Adrian Tuohy’s article “Commercial Fish Traps for Bycatch Mortality Reduction in Salmon Fisheries” in the January 2020 issue of The Osprey at https://www.ospreysteelhead.org/archives