henrys lake

Idaho Fish and Game staff conduct a gillnet survey on Henrys Lake recently to determine fish population, species and age makeup.

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Henrys Lake recently completed its annual trout checkup with Idaho Fish and Game just before the big Memorial Day weekend fishing opener, and things are looking close to management goals.

Hordes of anglers are expected for this weekend’s opening fishing day with all the adjacent Henrys Lake State Park campground sites taken.

Each spring when the ice goes off the lake, Fish and Game conducts a gillnet survey to check population, age, species and other data.

“This year we are less than we were last year for the number of fish that were caught,” said Fish and Game fisheries biologist Jenn Vincent. “We're at 10.6 trout for net night this year which is right below our management goal of 11 trout per net night.”

Last year the survey found 14.9 fish, the highest numbers in six years after a steady decline. Vincent said this year’s decline can be attributed partially to a reduction in fish stocked.

“We did stock less fish in 2020,” she said. “We increased our stocking to the lake for a number of years after seeing that decline in population (in 2016). We increased the stocking each of those four years. The other thing that plays a factor is the water quality and quantity in the lake. We've had three back-to-back high water quality years.”

Fish and Game started annual spring gillnet surveys on Henrys Lake in 1991. The lake is known for large cutthroat, cutthroat-rainbow hybrids and brook trout. Fish and Games website says “18-inch trout are common, but many fish much larger than this are found here.” Henrys Lake has a restricted bag limit of two trout, which includes brook trout. Once two fish have been harvested, anglers must stop fishing for the day.

Vincent said cooler temperatures should keep trout closer to shore this opener, allowing bank anglers some success.

“Last year most of the trout had started to move away from the shallows and into deeper waters,” she said. “The bank anglers weren’t as lucky as in years past. I don’t think that is going to be an issue this year. They're still hanging out in the shallows."

Vincent said a slightly lower count in the spring survey shouldn’t be noticeable by most anglers. The survey did show a good proportion of larger fish.

“We're right at where we want to be for the lake,” she said of Fish and Game goals. "Last year we had a large age 2 group of cutthroat trout. Now this year they’ve moved into age 3, so they are a little bit bigger than they were last year, but there is still a large number of them in the population. We have a large number of age 2 coming up behind them.”