Henrys Lake set to overflow with trout




REXBURG — With cutthroat spawning in full swing, an immature Bald eagle perched on a tree near the raceway running into the Henrys Lake Hatchery looking for an easy breakfast. Breakfast was not served.

“I come out once in a while to see if we have any floaters,” Nancy Olsen, an Idaho Fish and Game fish technologist, said as she went out to help a fish that was swimming on the surface. “This is the hump-backed one we had trouble with and we may not be able to save it.”

After working with the fish, Olsen was able to get the fish to swim normally and the eagle went without its goodies for a bit longer.

“Most of the fish we spawn are three- and four-year olds and near the end of their life,” Damon Keen, manager of the Henrys Lake Hatchery said. “Due to their age only half of spawners whether here or in the streams will still be alive by the time the season opens.”


Spawning began on February 19 with the eggs from the first two days being used to create hybrids as the eggs were fertilized with rainbow milt. Since then over two million eggs have been taken to insure the Yellowstone cutthroats stay dominate in the famed Henrys Lake.

Last year the goal of the Fish and Game was to plant 750,000 cutts, but due to the low water in the tributaries during the summer, there was very little natural reproduction and the plant was bumped up to around 900,000. This year the goal is to plant one million fingerling cutts in the fall. There should be plenty of eggs available for them as each female is producing about 2900 eggs and 1000 females have been spawned with the run half over.

“The oxygen level was good all winter long and the fish are in great shape producing good eggs,” said Keen. “Our spawn house is now full and we will have to ship them to the Mackay and American Falls hatcheries before we can spawn anymore.”


Taking eggs from the females is a detailed operation. One person holds the fish and starts stripping the eggs as another person, usually Keen, inserts a needle from a compressed air canister forcing the rest of the eggs out. Once the eggs are placed in a tub the fertilization is done.

“Each batch has the eggs from seven females and are fertilized by mixing them with the milt from seven males,” Olsen said as she stirred a batch. “The use of seven of each insures good fertility and the genetic make-up of the future fish.”

With hundreds of fishermen planning on fishing Henrys Lake as it opens on May 28, and in the future, the spawning program is essential for their enjoyment. And with half of the spawners dying of old age, the eagles will have plenty of snacks.

“I am kind to these fish as we spawn them,” a fisherwoman from Idaho Falls, Susan Henderson, said as she held a female as the eggs were taken. “I want to catch her later this year.”


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