World Fish Migration Day celebrates the wonders of migratory fish and raises awareness of the many obstacles that can prevent them from reaching destinations in the rivers and the spawning grounds they seek. Pacific salmon are one group of fish that can undertake remarkable migrations. Wild Pacific salmon can journey thousands of miles between the freshwater rivers where their life begins and ends, and the waters of the North Pacific Ocean where they go to feed and prepare for the passage home.
Prior to the arrival of humans in North America, barriers to salmon migrating through rivers would have included things like landslides, waterfalls, glaciers, and other natural obstacles. But in the last 200 or so years, many new obstacles have been placed in the path of migrating salmon, and not just within the river. In addition to the waterways now blocked by dams, flood gates, roads, culverts, and more (see our companion story salmon don’t know borders), Pacific salmon must navigate a gauntlet of nets and hooks set in the ocean to intercept and catch them as they attempt to return to the rivers of their birth. The term “escapement” is used to describe the number of migrating salmon that actually manage to “escape” these barriers of hooks and nets and reach their spawning grounds to reproduce.
At Raincoast, we are particularly concerned about fisheries called “mixed-stock interception fisheries”. As their name implies, these ocean fisheries “intercept” many species and populations of salmon migrating down the Pacific coast toward their natal rivers and streams. These fisheries, conducted by both Canada and the US, can intercept salmon thousands of miles from their rivers and spawning grounds.
“It is impossible to know which river the salmon are headed for when they encounter the nets and hooks of the fleet, or how many salmon from endangered populations are being removed while fishing is occurring. The presence of many salmon from small or weak populations mixing with those from stronger populations is what makes ‘mixed-stock interception fishing’ risky and unsustainable.”
The Gauntlet: In 1977, Clint Eastwood managed to beat the odds and make it through opposing forces in his fictitious movie. In 2021, the real-life outcome for many BC salmon was quite different. Thousands (and in some cases, tens and hundreds of thousands) of sockeye, Chinook, chum, and pink salmon destined for rivers in British Columbia were caught by the fishing fleet in Southeast Alaska before making it across the Alaska /BC border. (See the press release, backgrounder and report on this issue.)
One problem with mixed-stock interception fisheries is that they encounter many populations and species of salmon that migrate together. When they are intercepted by commercial or recreational fishing gear, they can be caught. Today, these caught salmon increasingly include fish from threatened and endangered populations. It is impossible to know which river the salmon are headed for when they encounter the nets and hooks of the fleet, or how many salmon from endangered populations are being removed while fishing is occurring. The presence of many salmon from small or weak populations mixing with those from larger populations is what makes ‘mixed-stock interception fishing’ risky and unsustainable.
Raincoast advocates for sustainable fisheries that occur in or very near the rivers where salmon are headed. This enables the fisheries to occur on “known” stocks of salmon, not “mixed stocks” of “unknown” salmon.
Terminal (river) fisheries have many benefits. Importantly, they operate on a scale that reflects the “placed-based” nature of wild salmon, a concept that recognizes the ecological connection between the wild fish and the natal watersheds in which they spawn, rear, and locally adapt. Persistence of salmon diversity, life history complexity, and local abundance are fundamental to ensuring the viability and resiliency of salmon populations over the long term.
Terminal fisheries harvest mature salmon – adults that are ready to spawn. This is not always the case for mixed-stock fisheries. Marine Chinook fisheries, for example, are conducted on the rearing grounds of immature Chinook. As a consequence, the harvest includes the removal of Chinook salmon at ages and sizes earlier than maturity. This size-selective harvest pressure has been occurring for 100 years on the Pacific coast and is a likely factor in the younger, smaller fish observed today. While climate change and hatchery competition are also probable factors in the size declines being observed recently, declining size and age (at maturity) have been documented in Chinook since the first half of the 20th century. Harvesting only mature salmon (not just ones above a certain length) would likely help reverse this trend in declining size, age and corresponding productivity. (We have more to say on this topic so stay tuned!).
Terminal fisheries, especially ones that are truly selective, are the needed step in the evolution of sustainable salmon fisheries on the Pacific coast. Such a move would align salmon management with the people and fish who are shaped by the rivers and watersheds where they have lived for millennia.
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