Righting wrongs is a tricky proposition on the planet of fisheries conservation. Too usually, the challenges outweigh expectations. Simply as continuously, actuality units in, and desperation takes over. Take the Decrease Snake River basin in Idaho. These are rivers that move from the final, finest (and largely intact) spawning habitat for salmon and steelhead that someway handle to climb eight dams from the mouth of the Columbia via japanese Washington and into the Gem State. The Snake, Salmon and Clearwater rivers was once the stuff of legends – salmon and trout factories that attracted anglers the world over.
Right this moment, they’re merchandise of “shifting baseline syndrome,” the place anglers get enthusiastic about runs of steelhead that eclipse 30,000 fish. Even the “previous timers” have come to phrases with the truth that, earlier than 4 dams on the decrease Snake have been constructed in the course of the center a part of the final century, the runs have been generally 10 occasions that quantity, and infrequently even higher.
The salmon and steelhead that make their means up the Snake, Salmon and the Clearwater are the troopers of the anadromous fish world – actual warriors which have been via the trenches. The fortunate few that handle to make it to hatcheries or, higher but, assemble redds within the rivers’ higher stretches, have conquered the worst that mankind may throw at them.
After which, months later, when the smolts emerge from the gravel or are allowed to “escape” their hatchery confines and start their journey to the ocean, they, too, have to determine a solution to get the place they’re going. Sure, the dams are problematic. These juvenile fish usually get misplaced within the froggy backwaters the dams create. Usually, they’re preyed upon by all the pieces from stocked trout to launched populations of smallmouth bass.
And, now, in line with fisheries biologists on the Idaho Division of Fish and Recreation, one other toothy predator is taking a literal chunk out of each wild and hatchery salmon and steelhead as they navigate the more and more troubled waters en path to the Pacific: the walleye.
An consuming machine
Walleye are native to the higher Midwest and most of boreal Canada. Their regular prey base is smaller fish – minnows and shiners native to the lakes of their residence vary. However, in 2023, extra walleye have been reported in catches by anglers plying the waters of the Snake River in Hells Canyon and within the Salmon River upstream of its confluence with the Snake than in all earlier years mixed.
As in most states the place the fish will not be native, walleye have been deliberately launched in Idaho to offer a leisure fishery – the fish is widespread amongst anglers, each for its sport combat and its desk fare. Walleye, by most accounts, are completely scrumptious.
However the walleye discovered within the Snake and Salmon rivers are possible the merchandise of unlawful fish introductions that began properly downstream within the Columbia some 80 years in the past – during the last a number of a long time, walleye have apparently moved upriver into the decrease Snake and Salmon rivers. The primary walleye was confirmed through pictures in 2019, with anglers sending in one other confirmed walleye photograph in 2020. Three pictures of walleye have been submitted in 2022.
Given the shortage of forage fish in these rivers, the invasive predator should flip to different sources of meals. And, at any given time in the course of the yr when juvenile salmon and steelhead are making their solution to the ocean, they’re completely on the walleye’s menu.
Catch and kill
Simply this month, Idaho Fish and Recreation requested walleye anglers to be much less discerning and to kill and harvest each walleye they catch within the state’s salmon and steelhead rivers. However, within the large Columbia River watershed, the place the non-native fish are largely naturalized, is that this effort to proper a previous flawed prone to show profitable?
“Anglers have been nice about protecting us knowledgeable about walleye they’re encountering, and we tremendously admire that,” says Marika Dobos, a Lewiston-based fisheries biologist with IDFG. “We all know it may be an inconvenience to their fishing journeys, however catching, protecting and reporting walleye is the most effective software biologists have to observe the place these fish are migrating, estimating what number of is perhaps on the market, and in addition eradicating a few of them.”
And, frankly, that’s about the most effective we are able to count on. From right here on out, we are able to nearly all the time anticipate finding walleye within the Columbia drainage, together with within the Snake and Salmon rivers. And if the invasive fish isn’t already within the Clearwater drainage, it’s wager that it will likely be in time.
In 2023, 16 anglers reported catching 18 walleye. This information quantities to one more blow to the already severely diminished Snake River basin anadromous fishery. First, there are the dams. Throw in different launched fish within the Columbia’s decrease reaches, like smallmouth bass, largemouth bass and customary carp. Now, properly upstream of the place they have been ever anticipated, anglers are catching walleye, maybe essentially the most predatory invasive within the system.
Evolution be damned (or dammed?)
The salmon and steelhead of the Snake River basin advanced with valuable few piscine predators. The basin’s rivers, earlier than they have been dammed and rechanneled, hosted wholesome populations of hungry bull trout and it’s possible northern pikeminnows definitely grabbed their share of younger salmonids migrating to the ocean. However, in any other case, chinook and sockeye salmon, in addition to Idaho’s famed runs of large “B-run” steelhead made their solution to the Pacific largely unmolested.
In at present’s altered surroundings, the place dams have modified the river’s construction and launched species have modified its primary ecology, it’s a surprise any salmon or steelhead make it again to Idaho in any respect.
Add within the growing results of local weather change, and the decrease Snake and the Columbia, with their backwaters and sluggish currents, have gotten extra hospitable to fish like walleye than they’re to native salmonids. Based on IDFG, a 16-inch feminine walleye can produce 57,000 eggs in the course of the fish’s spawning season. Greater fish, as much as eight kilos, can produce 300,000 eggs.
What to do?
In truth, past what IDFG is recommending and hoping in opposition to hope that leisure anglers will observe via and kill each walleye they catch, there may be little or no to be accomplished.
That’s, there’s little or no to be accomplished in need of eradicating the 4 uppermost dams on the decrease Snake River, an answer lengthy advisable by science, however, save for a courageous few, a non-starter within the western political panorama
Actually, dam elimination would go a great distance towards releasing the Snake and returning the river to a way more pure situation. This alone would make the river much less liveable to invasives like walleye and perhaps even bass. I might additionally slice in half the variety of man-made obstacles salmon and steelhead must navigate en route the Pacific and again.
Till the political will may be discovered, we’re possible left the place we’re proper now, with ever-dwindling returns of salmon and steelhead and a future for the migratory fish that, even via essentially the most optimistic lens, seems to be mighty bleak.
