Fish hatchery seeks to rejuvenate prehistoric-aged species
Fish hatchery seeks to rejuvenate prehistoric-aged species
MOSES LAKE — The fish being tagged this week at the Columbia Basin Fish Hatchery are still pretty young, but hopes are high that they represent new longevity for their species.
The hatchery's program to replenish the white sturgeon population in Lake Roosevelt, in partnership with Canada, is presently within its third year.
"We're trying to recover the population because of lack of juvenile recruitment," said Brian Lyon, hatchery specialist. "Because they're prehistoric and have been around for millions of years, obviously we don't want these things to go extinct."
While adult sturgeon are spawning, Lyon said, the juveniles are not surviving, due to such factors as predators, habitat changes and water quality and pollution issues.
Washington Department of Fish and Wildlife fish biologist Jason McLellan said that the program will not see spawning benefits for many years, considering sturgeon reach sexual maturity at the age of 25 to 30 years old.
"This program is designed to provide future spawning fish until we can figure out what's causing a natural reduction in spawning success," he explained. "While we're not seeing benefits yet in spawning fish, because it will probably be 15 to 30 years before those spawn, we are seeing high survival rates of the fish, so our monitoring is indicating in the future we should have ample numbers if these fish survive."
The hatchery is raising sturgeon from eggs to a size large enough to have a better chance of survival when placed in the water. The hatchery receives the eggs and raises the young sturgeon for almost a year.
The present generation of sturgeon were received as eggs in June, Lyon said, and were pit-tagged and scute-marked this week in preparation for their release at three different locations from Kettle Falls and northward in mid-May. Lyon said two families were marked, making for a total of 2,000 fish.
"This is so that when we go back out on the river and we recapture fish, we can identify those fish as what brood year they are, where they came from and give us an idea of how fast they are growing, where are they moving up and down the river, how many are surviving," Lyon said.
Generations of sturgeon are being lost as the offspring of those at the age of sexual maturity fail to survive, McLellan said, and without the replenishment of new fish, there will be a large gap between the time of figuring out the problem and determining its solution.
"The way the situation currently is, we already have a large gap in time between the last successful wild reproduction and recruitment, and our current hatchery supplementation," McLellan said, estimating that gap extends 20 years.
Lyon said the sturgeon have to be trained how to feed, because the species are bottom feeders which use their senses to smell food.
"For us at the hatchery, we actually have to introduce the feed first of all just for the smell, and later on in time we introduce it to them for them to eat," he said. "It's a pretty tedious process, and it's a real crucial process, because if we don't get them eating at the time when they're ready, you can have a lot of drop-outs."
"Sturgeon are an important species because they're a vital part of the ecosystem and they've been a part of it for thousands of years," McLellan said, adding there's a strong sport-fish value to the species. "Historically, there's always been a fishery in Lake Roosevelt for sturgeon, even up to the point where we closed it to protect the population."
The long-term goal is to restore natural recruitment to a level where some sport fish can be retained, at the very least providing a catch-and-release opportunity to the public, and have it be supported by natural reproduction, McLellan said. Once natural reproduction has reached a level where it is considered appropriate, the department will discontinue hatchery reproduction.
"The interests here aren't to preserve a museum-piece population," he said. "Our goal is to restore this population to where it's a healthy, vital part of the ecosystem, as well as being able to provide some beneficial uses."
If anglers are fishing on Lake Roosevelt and catch a sturgeon, McLellan asks that the fish are handled carefully and placed back in the water as quickly as possible.
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