Oct. 17–ROGERSON — Scott Stanton steers a small motorboat into a cliff-lined corner of Salmon Falls Creek Reservoir — close enough to the southern end to hear the honking on Goose Island — and stops beside a buoy marked “scientific sampling gear.”
As bio-aide Damian Hainer hauls up a long gill net, fish after fish flop into his tubs: trout, suckers, northern pikeminnows and finally the walleye these men are after.
“Be careful with him, because he’s barely hanging and he’s on small mesh,” the regional fisheries biologist tells Hainer.
On shore at Greys Landing, south of Rogerson, wait the Idaho Department of Fish and Game colleagues who will measure, weigh and dissect each walleye caught in their six gill nets. This Oct. 8 research will provide data on the sport fishery’s health and condition — data meant to compare Salmon Falls Creek Reservoir’s walleye with fisheries elsewhere in the U.S. and Canada. Their standardized protocol: “fall walleye index netting.”
Idaho walleye anglers asked for this monitoring. Almost a decade ago, they suspected overharvest and feared a collapse of the walleye fishery here — one of only three in Idaho.
So Doug Megargle, regional fisheries manager, initiated three years of baseline index netting at Salmon Falls Creek and Oakley reservoirs. (One immediate finding: The walleye were still plentiful at Salmon Falls. They just had plenty to eat that year and weren’t biting for anglers.) Now, five years later, the fall walleye index netting is beginning its twice-a-decade schedule at Salmon Falls.
Five years is long enough to forget.
“It’s kind of like having a second kid: ‘Oh, now I remember,'” says Regan Berkley, kneeling in the cold sand of Greys Landing with a small pick. She’s freeing fish from a gill net.
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As Stanton and Hainer return in the boat with more heavy tubs, Fish and Game workers spread long nets on the sand. Each with a net pick like Berkley’s, they kneel in a line of bent backs. It’s laborious work.
“We often get volunteers one year. Not so much the second year,” Megargle says.
On the back of each pick is a “frustration blade,” and the dozen pickers have Megargle’s permission to use it.
The crew’s numbered tubs track which sand-coated trout and suckers came from which randomly selected location in the reservoir. But walleye are counted and dropped into wet burlap sacks, to wait underwater at the reservoir’s edge.
Among the pickers in waders and gloves is Lisa Lam, a seasonal employee of the Idaho Department of Health and Welfare. She’ll take some of the walleye, when today’s researchers finish with them, for Health and Welfare to test for mercury and other bio-accumulated substances.
The mercury cited in Health and Welfare’s fish-consumption advisories builds up in the tissues of big fish that eat smaller fish in this reservoir. After they switch from eating insects and plankton, Salmon Falls walleye begin a diet of yellow perch, juvenile sucker, northern pikeminnow, spottail shiner, redside dace, crappie, juvenile walleye and stocked rainbow trout.
Fish and Game reservist Derek Thomas of Burley plucks a northern pikeminnow from the teeth-lined mouth of a walleye, and Megargle lays the pikeminnow on the walleye to compare their sizes. The eaten is half the length of the eater.
Also among the net pickers is Jeff Dillon, the state fisheries manager from Fish and Game’s headquarters. He and Megargle talk quietly about the sizes of walleye they’re seeing in the nets.
Anglers lately have reported catching smaller walleye, Megargle says. The explanation might be a big spawning year in 2009 or 2010, and fish of that age might be more abundant in the reservoir.
He’s hoping to see most age years represented in this day’s catch — one indication of a healthy fishery. Today’s measurements also consider annual mortality, a fish’s length at age, its condition (reasonable weight for length), proportion of males to females, age at sexual maturity, physical deformities and fat weight. Fat tells biologists something about the forage availability in Salmon Falls Creek Reservoir.
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Idaho Walleye Unlimited is particularly interested in this data, to draw anglers to its tournaments on the reservoir.
Its classic, the Father’s Day walleye tournament, attracts 40 to 60 boats, says club member David Keever of Twin Falls. He’s at Greys Landing today to wait for the walleye not claimed by the Health and Welfare representative. Their destination: club coolers, then a fish feed.
The Father’s Day tournament used to draw competitors from as far away as the Dakotas. But in harder economic times, most out-of-staters are from Utah now, Keever says.
The local club uses its conservation budget from a national walleye federation to plant habitat in the reservoir — dead junipers, cabled together and anchored.
As Keever talks and the research crew folds empty nets, a chilling wind kicks up sand and whips a pair of tents. Gulls circle above Greys Landing. Fish and Game employee Jennifer Posey holds up a big walleye for her colleagues’ camera phones.
“He’s probably an original planter, back in ’73,” Keever says.
Fish and Game imported and released walleye in three Idaho reservoirs, the state’s only sanctioned walleye fisheries. Fish and Game will do its fall walleye index netting next year on Oakley Reservoir, also called Goose Creek Reservoir. The third and less important walleye fishery is Oneida Reservoir near Pocatello.
Keever didn’t know what walleye were when he moved to Twin Falls in 1974. He remembers a puzzled trout fisherman in the ’70s bringing a walleye into Blue Lake Sporting Goods to get it identified.
Idaho anglers aren’t puzzled anymore.
“We quit eating trout when I got onto these a few years ago,” says Idaho Walleye Unlimited member Earl Olsen of Twin Falls, pulling coolers out of a truck beside the researchers’ tents.
Treat walleye right and it tastes like lobster, adds club member Terry Reeves of Twin Falls.
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Fisheries technician Joan Harding, the note taker of today’s fall walleye index netting, needs to log 200 walleye in her field notebook with the yellow waterproof cover. Her penciled figures total only 172, so the men on the boat will reset two gill nets and the researchers will be back tomorrow.
But today’s catch can’t wait — at least not longer than it takes for Harding to feed the crew a lunch of pulled pork sandwiches on paper plates.
Stanton divides the crew into two teams: one for walleye, one for everything else.
In the non-walleye tent, regional wildlife biologist Brad Lowe lays one fish at a time into measuring trays manned by Berkley, another regional wildlife biologist, and Randy Smith, regional wildlife manager. Berkley and Smith announce species and lengths to Megargle, who types them into a handheld computer. “RBT 406” is a rainbow trout, in millimeters. “LSS 540” is a largescale sucker.
“They’ll all be rounded anyway,” Megargle says, getting a reaction — and laughter — from Smith and Berkley.
Smith has been killing his eyes trying to read millimeters, he says. But he keeps announcing exact measurements anyway: RBT 347. Chiselmouth chub 171.
As Lowe quickly empties tub after tub, Hainer’s tubs fill. He’s at Megargle’s elbow, puncturing the air bladder of each sucker, trout or chub with a knife. It’s a job descriptively dubbed “fizzing.”
These non-walleye will be recycled — their carcasses dumped into the water to be eaten, returning their nutrients to the reservoir’s ecosystem. The fizzing ensures they’ll sink. Fish and Game doesn’t want anglers reporting a fish kill.
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Work in the walleye tent is slower and more deliberate. Blowing sand accumulates on the scales, and everyone squints as Stanton hands out the jobs.
Dillon washes the sand off each walleye in a bucket, measures its length and holds it in the weighing pan for Lam to lodge a tiny, numbered scrap of paper in the corner of its mouth. Sally Rose, a Fish and Game administrative assistant, reads off the walleye’s weight for Harding, who records everything in a handheld computer.
Stanton takes the job he calls “crackin’ backs.”
He slits open each fish and piles the fat from its body cavity onto a paper plate on the scale in front of wildlife biologist Bruce Palmer. While teaching Rose how to determine walleye sex and maturity, Stanton extracts each walleye’s gonads and skeins for a separate weighing.
Then Stanton does something more precise than it appears: With pliers, he cracks the walleye’s spine at just the right point and pops open its head cavity to reveal the two otoliths. He picks out each tiny otolith with forceps and smears away its mucus on the back of his glove.
Those bonelike plates from each walleye ear will be stored in vials for now. Later they’ll be cut, sanded and examined under a high-resolution microscope to determine the fish’s age. Scientists read otoliths like tree rings — one new ring a year.
Stanton’s back cracking also reveals something that nobody measures but everybody respects: the walleye’s teeth.
Translucent, sharp and numerous, they’re the terror of Salmon Falls Creek Reservoir.