Lethal Fish Trap Gets Second Chance as Recovery Tool
Once regarded as “the most murderous and iniquitous instrumentalities ever devised to destroy natural life,” fish traps will be given a second chance in 2016. Although fish traps were commonly blamed for the decimation of Washington State’s salmon populations and the monopolization of salmon fisheries by the canning industry in the early 20th century, nearly eighty years after the fixed-gear ban of 1934, fish traps may once again prove their worth to fisheries of the Pacific Northwest—this time, as tools for sustainable fisheries and the conservation of threatened and endangered wild fish.
Readers may be wondering at this point, “How can commercial fish traps ever play a role in promoting sustainability and the recovery of Washington’s imperiled wild fish?” After all, fish traps were widely known as the most efficient and effective commercial fishing tools used for the slaughter of wild fish in the region. A single trap, for example, could catch as many as 1.2 million salmon per season. The answer to this question, however, lies in the unique method through which the fish trap captures and selectively harvests migrating adult salmon.
Fish traps are constructed utilizing knowledge of adult salmonid behavior. As adult fish return upriver to their natal watersheds to spawn, they frequently remain close to shore, in slower waters where they can minimize energy expenditure for the long and arduous journey ahead. Fish traps are constructed in the migratory paths of returning salmonids. Consisting of a series of pile driven and floating web fences that extend from the high water mark to the river or estuary bottom, fish traps guide salmon from the shoreline through a large maze of walls and compartments. Since migrating salmon tend to forge ahead and rarely choose to turn backward, salmon move steadily through a trap’s strategically designed inner-compartments to a large corral from which they cannot escape.
The final compartment of a fish trap, known as the spiller, is what provides the gear-type with its potential to be perhaps the most sustainable method developed for the capture of salmon. Unlike gillnets or seines—which inflict serious physical and physiological damage to fishes through wedging, gilling, and scale loss—salmon captured within the spiller of a fish trap are able to swim freely with a constant supply of free flowing, oxygenated water. Fish that are desired for harvest can be removed from the spiller alive and in excellent condition; those that are of a non-targeted species may be set free without causing harm or mortality. Through this method, fishers are given the unique ability to selectively harvest targeted hatchery stocks and successfully release threatened or endangered wild stocks that are mixed within the fishery.
The reduction of bycatch mortality and improvement of selective harvest have been the main goals of the Washington Department of Fish and Wildlife’s Lower Columbia alternative gear studies, which have been ongoing since 2009. With our State’s continued reliance on ecologically inadvisable hatcheries to prop-up salmon fisheries of the Columbia River, the Fish and Wildlife Department has expressed a great need to develop selective commercial fishing tools to reduce overharvest of non-targeted stocks and ensure the removal of hatchery fish to prevent dangerous levels of interbreeding with threatened and endangered wild fish. Nevertheless, while previously tested alternative gears (including beach seines, purse seines, and modified gillnets) have continuously failed to show promise in substantially reducing bycatch mortality since the studies began, Washington State has not held back from releasing hatchery fish into wild salmon rivers. Furthermore, gill nets—which inflict bycatch mortality rates as high as 75%—have continued to remain in operation, resulting in the unintentional overharvest of species listed under the Endangered Species Act. Clearly, there is an urgent need to either put an end to the release of hatchery fish, or rapidly develop a viable alternative gear-type to enhance harvest of the State’s detrimental hatchery stock and reduce bycatch mortality of threatened wild fish.
Working to solve the harvest problem with local commercial fishers of the Lower Columbia, Wild Fish Conservancy is in the process of designing and constructing the first fish trap in Washington State waters in over eighty years. Funding has been secured and testing will be underway in 2016 to determine whether an ancient technology may provide an answer to a modern fisheries crisis. Assuming the experiment proves successful, a sustainable future may be developed for both wild fish and coastal fishing communities of the Pacific Northwest.