Keywords: Species and food webs, Fishes, Freshwater habitat, Salmonids, Elwha River, Salish Sea Currents magazine

The return of sockeye to the Elwha River is intriguing scientists. Could nearby freshwater kokanee help re-establish resident populations? We continue with part four of our series 'Returning home: The Elwha's genetic legacy.' 


When discussing the future of the Elwha ecosystem, many scientists have advanced the exciting possibility that ALL species of Pacific Salmon — including the lake-dwelling sockeye — could make their home in the watershed. The prospect of native sockeye returning to the Elwha is made possible by the existence of Lake Sutherland, located about 10 miles west of Port Angeles.

By all accounts, that native migratory population of Oncorhynchcus nerka died out soon after the Elwha Dam blocked the upstream passage of these red-bodied fish with green heads.

The 1.7-mile-long lake is small compared to the adjacent Lake Crescent (11 miles long) or well-known sockeye lakes on the Olympic Peninsula, namely Ozette (10 miles long) and Quinault (4 miles long). Yet Lake Sutherland is the only lake draining into the Elwha River, and historical accounts suggest that this body of water once supported a sizable run of sockeye, sometimes called red salmon.

By all accounts, that native migratory population of Oncorhynchcus nerka died out soon after the Elwha Dam blocked the upstream passage of these red-bodied fish with green heads. Considering today’s housing developments around the shoreline of Lake Sutherland, scientists aren’t sure how much suitable habitat remains. And yet Elwha researchers are intrigued by the genetic makeup of a landlocked population of kokanee — the resident form of the species — that lives on in Lake Sutherland.

A lake seen through trees on the near shore with houses along the far shore.

Houses seen along Lake Sutherland, the only lake draining into the Elwha River. Historical accounts suggest the lake once supported a sizable run of sockeye salmon. Photo: Sheila Sund (CC BY 2.0)

 “Whether or not sockeye salmon will re-establish a self-sustaining population is perhaps one of the biggest unknowns of all salmonid species in the Elwha River basin,” states a 2008 article in Northwest Science by George Pess of the Northwest Fisheries Science Center and others discussing the prospects of sockeye recovery.

Unlike the steelhead/rainbow trout connection, resident kokanee typically do not contribute much to migratory populations of sockeye. With their unique evolutionary history, sockeye and kokanee can coexist with little interbreeding, although they do occasionally get together and produce viable offspring. In the Elwha, no juveniles have been seen leaving Lake Sutherland, and adult sockeye returning to the river from saltwater appear to be strays from other rivers — potentially as far away as northern British Columbia, Canada, according to genetic studies.

Typically for the species, sockeye spend their early growth period in a lake, often hatching in a stream that drains down into the lake. Although Lake Sutherland has a few small streams flowing in, none are large enough to support much spawning, experts say, so female kokanee generally lay their eggs around the perimeter of the lake. Years ago, Lake Sutherland sockeye probably started their lives in a similar way, emerging from the gravel near the lake’s edges to spend a year or two in deeper water. They would then move downstream into Indian Creek, which enters the Elwha just above the site of the former Elwha Dam.

In prehistoric times, the lake flowing into the Elwha was much larger, according to geologists who say that today’s Lake Crescent and Lake Sutherland were once a single lake. As a result of one or more major earthquakes, big chunks of land slid into the lake, forming a natural dam more than a mile wide. Today, motorists traveling on Highway 101 west of Port Angeles drive across over this ancient dam while viewing the crystalline waters of Lake Crescent out their car windows.

The Lake Crescent kokanee may be descended from ancient sockeye that once migrated through the Elwha River.

Lake Crescent no longer drains eastward into the Elwha River. The natural dam forced the lake level to rise 80 feet higher than Lake Sutherland. As the waters rose in Lake Crescent, they eventually found a new escape route by spilling into the Lyre River, which flows northward to the Strait of Juan de Fuca. Because of an impassible waterfall, adult salmonids cannot come into Lake Crescent for spawning.

Nevertheless, over several thousand years, landlocked populations of rainbow trout, cutthroat trout, kokanee and others have evolved in Lake Crescent. Despite plantings from other river systems, Lake Crescent trout remain genetically distinct and among the largest of their kind in the Northwest. A rainbow and a cutthroat trout from Lake Crescent both hold records as the largest of their kind caught anywhere in the state with a rod and reel.

Some researchers say the inordinate size of these fish is likely connected to their diet. Instead of eating aquatic insects, as many trout do, the Lake Crescent trout largely consume kokanee after they reach a certain size, according to studies. Perhaps because of their diet, the Lake Crescent trout seem to outcompete nonnative transplants, which remain scarce in Lake Crescent.

The Lake Crescent kokanee may be descended from ancient sockeye that once migrated through the Elwha River. While today’s population may be influenced by hatchery transplants from 1913 until 1939, limited genetic data suggest that Lake Crescent kokanee are distinct from the hatchery stocks planted in the lake, according to Pat Crain, chief fisheries biologist for Olympic National Park. It is quite possible, he said, that the kokanee in Lake Sutherland and Lake Crescent maintain similar genetic identity, despite their physical separation.

In Lake Sutherland, today’s kokanee population shows signs that it may carry genetic traits from an extinct sockeye population. Eggs of the Lake Sutherland kokanee are larger than for typical kokanee seen in other lakes — more like the size of typical sockeye eggs, according to Tom Quinn, a research professor in the University of Washington’s School of Aquatic and Fishery Sciences. Since the genetic makeup of the lost sockeye cannot be reconstructed, researchers can only speculate about the meaning of that size difference.

During recovery planning before dam removal, some experts expressed hope that the Lake Sutherland kokanee might become migratory and begin a new run of sockeye. So far, it appears that such a revival of a migratory kokanee has not occurred — unlike the restoration of native steelhead from the lingering rainbow trout population in the upper Elwha. Smolt traps on Indian Creek operated each year by the Lower Elwha Klallam Tribe capture out-migrating juveniles, but so far no kokanee/sockeye have been captured, noted Mike McHenry, the tribe’s habitat manager.

During recovery planning, officials considered a moratorium on kokanee fishing in Lake Sutherland to build up the population with a hope of pushing a portion of the fish into migration, McHenry said. In some other systems, including two rivers in British Columbia, large kokanee populations appear to have triggered anadromy, he noted. In Lake Sutherland, sport fishing interests opposed a moratorium, and the idea never gained support from the Washington Department of Fish and Wildlife.

The end of migratory sockeye runs in the Elwha River is believed to coincide with blockage by the lower dam starting in 1911. Over time, a few sockeye still showed up in the river below the dam, but they were considered likely strays from other sockeye rivers with almost no chance of successful spawning.

As part of the recovery investigation, one study captured 45 sockeye found in the river from 2010 to 2017 — before and after dam removal — and then used genetic techniques to identify where the fish originated.

“None of the fish came from the Lake Sutherland population,” said Quinn, who led the study published last year in Transactions of the American Fisheries Society.

The source of the sockeye found recently in the Elwha remains a mystery, although riverine sockeye do show up each year in some rivers on the Olympic Peninsula.

In fact, none of the 45 sockeye found in the Elwha showed a genetic signature that would link them to any nearby sockeye river, based on a genetic “baseline” of available sockeye populations in the U.S and Canada. Although one of the sockeye likely came from the Fraser River population just over the Canadian border, 22 were more similar to populations along the West Coast of Vancouver Island while another 22 seemed to come from populations farther north, such as the Stikine River near Southeast Alaska, all in British Columbia. Since genetic data are not available for all populations of Northwest sockeye, it is possible that some of them came from a closer population whose genome is not yet identified, Quinn acknowledges.

Interestingly, the populations linked to the West Coast of Vancouver Island are considered lake-type sockeye, which spend their early lives in lakes, whereas the more northern group is mostly riverine sockeye, a sporadic breed of sockeye than can survive in a river without a lake.

Quinn’s analysis considered a previous genetic study of 8,726 sockeye caught in Canadian waters, just over the international border in the Strait of Juan de Fuca. The study found that only five of those fish had a strong genetic link to the Stikine River, so it is unlikely that strays from that distant population were visiting the Elwha.

“The most likely explanation,” according to the research report, “is that the sockeye salmon sampled in the Elwha River were from populations nearer to the Elwha River that resembled the Stikine River genetically.”

The source of the sockeye found recently in the Elwha remains a mystery, although riverine sockeye do show up each year in some rivers on the Olympic Peninsula. Biologists who conduct spawning surveys have spotted what they believe to be small numbers of riverine sockeye in the Dungeness, Sol Duc, Calawah, Hoh and Quinault rivers, according to Crain of Olympic National Park. Riverine fish generally look more robust than lake-type sockeye, and they spawn within a month or so of arrival. In contrast, lake-type sockeye tend to arrive earlier and spawn later than riverine sockeye. Since little or no genetic testing has been done on these fish, nobody can say if the sockeye seen in the Elwha might have strayed from one or more of these rivers.

So far, biologists have not even established whether Olympic Peninsula streams contain identifiable and sustainable populations of riverine sockeye, Crain said. Research has shown that this type of sockeye is known to stray into other streams at a much higher rate than sockeye that start their lives in lakes. And genetic studies have shown that riverine sockeye as a group are more related to each other than to sockeye in nearby lakes, which often have unique genetic signatures.

This tendency to stray could be an evolutionary strategy to maintain the riverine population, Crain said, and it is possible that riverine populations on the Olympic Peninsula are fairly well mixed. More research is needed to better understand these relationships.

Now that the Elwha dams have been removed, there is no doubt that sockeye from other places are coming into the Elwha River and moving upstream. In fact, trace amounts of sockeye DNA were found in water samples far above Glines Canyon, confirming that the species is capable of making it into the upper watershed.

Whether visiting sockeye will find a suitable home in the Elwha and begin a new population remains to be seen. Perhaps a lake-type sockeye can adapt to conditions in Lake Sutherland, possibly by breeding with the long-established kokanee already there. Perhaps riverine sockeye can gain a foothold by finding an ecological niche somewhere within the diverse habitat now open to them.

If humans were to intervene more forcefully, researchers could look for a population of sockeye to transplant from somewhere else. For now, restoration managers seem content to observe how nature itself adjusts to the newly restored conditions.

Up next: Opening the door for coho, chum, and pink salmon.

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Following dam removal, migratory salmon have been free to swim into the upper Elwha River for the first time in 100 years. Their actual behaviors and reproductive success may well be driven by changes in their genetic makeup. Our seven-part series 'Returning home' examines how the fish are doing and whether the Elwha's genetic legacy remains intact. 

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About the author: Christopher Dunagan is a senior writer at the Puget Sound Institute.

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