Wildlife Watch: Monitoring walleye on the Winooski

Published: Apr. 13, 2021 at 7:01 PM EDT
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WINOOSKI, Vt. (WCAX) - Vermont Fish & Wildlife biologists sample walleye in Lake Champlain tributaries every spring to monitor the health of the species. Our Ike Bendavid recently joined a crew on the Winooski River to learn more about the life cycle of the walleye.

On the banks of the Winooski River, Vermont Fish & Wildlife biologist Bernie Pientka and his crew are getting ready to hit the water. “We are doing both a walleye assessment, where we go in and check the spawn, looking at age structure, size, lamprey wounds, and we are also taking fish for the hatchery,” he explained.

Pientka says the walleye sampling happens every year in different rivers around the state. “We do a rotational egg take by river, so this year we are on the Winooski River. Last year we were on the Poultney River. Next year we will be on the Missisquoi. We take females and males to the hatchery. We will spawn them out and then they will grow fingerings -- up to 2 inches -- in the hatchery, and then we will stock back into the rivers,” he said. Pientka says this is done to help monitor the population of the fish and make sure the species is healthy. The state says the fish that are raised in a hatchery have a better chance of survival.

While on the boat, The crews put out a measured shock into the water to collect the fish. “These big spiders that come out are actually connected to a unit and we are putting pulse electricity in the water and it stuns the fish and then they float up to the surface and we are able to net them. They come out of that in about 30 seconds to a minute,” Pientka said

As fish float up, the crew scoop them up with a net and put them into a tank on the boat. “We try to pick through the suckers that are floating and get the walleye that are floating into the boat. Our strategy is to get 50 pairs -- male and female -- to the hatchery to produce next year’s walleye,” said Dave Gibson, a fisheries specialist.

This all happens while Pientka tries to negotiate the boat through the fast-moving, low water on the river. “As you do it, you pick up areas that the fish tend to congregate, and you kind of just learn it after doing it over the years. So, it’s kind of like, how do I get the boat to go through that area I think they are going to be at in a way that I can effectively sample them. And then you’re always going, ‘Where is that big rock, where is that tree stump I hit the other year,’” Pientka said.

When the tanks are full, the crews head back to shore to get biological information about the fish. “We examine those fish and look for marks that indicate what percentage of the fish we stock are we seeing back here three years later. And for the Winooski River, we have been seeing some pretty high percentages of our stocking and fish returning to the river,” Pientka said.

“By tagging and marking the walleye that we have stocked, we see a great percentage of walleye here in the river is from stock,” added Gibson. “If we didn’t have the walleye program at the hatcheries, the walleye population would be greatly reduced.”

Many of the fish that were sampled will be put right back in the river in a few months. For anglers, walleye seasons starts May 1.

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