At nearly 7,000 feet, Henrys Lake nestles nearly atop the continental divide, between Idaho and Montana. It's a shallow lake, averaging eighteen feet in depth. But it is exceptionally fertile, with dense aquatic vegetation that hides abundant numbers of insects, freshwater shrimp, sculpins, and larvae.
There's really no lake in Idaho that can compare to the high catch rate of Henrys Lake. Cutthroats, brookies, and rainbow-cutthroat hybrids -- they're all here, in sizes and lengths that lure anglers from all over the country.
Because of its location and elevation, the lake freezes over early and can stay frozen til nearly summer. But even with four feet of snow on the lake, there is life under the ice.
Hundreds of large trout work their way up the fish ladder to spawn, right into the waiting hands of a room full of biologists and volunteers.
"The fish come up the ladder into a trap and daily we sort the fish," says Idaho Fish & Game biologist Damon Keen. "We identify females from the males, and we put them in a different location within the trap. Annually we'll trap three to four thousand fish. We'll take about four to five million eggs in the next month and a half, so we'll be very active."
Damon Keen has been part of this March madness for more than a decade, but he's still impressed. "Daily, I'm amazed at the size of the fish and what a terrific fishery we have here at Henrys Lake. These fish average anywhere from 17 to 20 inches. We do see some 7 to 10 pound fish come up the ladder that are hybrids normally; we don't spawn hybrids, because they aren't fertile, but the cutthroat will be 17 to 20 inches.
Keen gets lots of help from volunteers. "We have all the volunteers we would ever need, and we usually have more than we ever need; we never turn away volunteers. People are very anxious to help and willing to help."
The eggs are shipped to the Mackay hatchery, but eventually 95% of them will return here to Henrys Lake as fingerlings, to complete the cycle. But some will have a higher calling, in Idaho's high mountain lakes.
The hike to Brockie Lake in the Copper Basin is only about a mile and a half, but it's pretty much straight up. You go from 8,000 feet to 10,000 feet, with few switchbacks. Now pack on an extra 30 pounds of water weight, and you've got yourself one tough climb. The bags they carry are full of fish and oxygen and three gallons of water. They slosh back and forth with every step.
“This is probably in the top ten as far as difficult to get to,” says Fish & Game fisheries manager Dan Garren. Garren and colleague Greg Schoby are taking cutthroat fingerlings to Brockie Lake. Their cargo has only a five-hour survival window, so turning back is not an option.
“We brought 1500 fish in here today. Of course they have to come with water and water is fairly heavy. So we have pretty heavy packs and a lot of elevation gain, and it can be a little difficult. The longer they stay in the bag, the higher the mortality.”
High mountain lakes, like Brockie, are stocked statewide in the fall. Some regions have hundreds of lakes. The upper Snake region has about 50, managed on a three-year rotation. And many of these lakes are stocked on foot, rather than by air.
“It’s a lot of work. It’s a lot of struggling to get up here, but it's also rewarding. You’re creating a fishery that somebody is going to come up and really enjoy when they get here.”
The men place the bags in the shallows, so the fish can acclimate properly. “Any time you introduce a fish into a new fishery, it takes some time to adjust, especially when it spent all its life in a hatchery. We put the bags in the water to kind of equalize.”
While the temperature equalizes, the biologists check the lake for signs of traffic. They also track the progress of fish stocked three years ago. That requires tossing a line into the lake to verify catch rate.
Most high mountain lakes have a catch rate of one fish per hour, but some actually have much better odds than that. Garren and Schoby catch a dozen trout in 15 minutes.
On this day they found fish all the same size, about ten inches. That's pretty consistent with the stocked fish of three years ago. Based on that alone, they can tell that natural reproduction is pretty low here.
"Everyone knows Henrys Lake, but very few people know about Brockie Lake. There are lakes all across the state that are good fisheries, but you have to do your legwork to find out where they are and which ones have good fishing. So you gotta work to figure them out and then you gotta work to get here.”
When the anglers get here, the fish will be here.
“Its kind of cool. It’s rewarding. You know you’re doing something good for the fishery.”