Toothy fish gets special attention

Posted 6/8/17

“They’re a pissed-off fish,” said Joe Skorupski, fisheries biologist for the Wyoming Game and Fish Department. “They get angry when touched.”

But the goal was to make anglers fishing for the feisty, toothy, native fish happy. And the …

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Toothy fish gets special attention

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Game and Fish studies best water temps for sauger

A team of Wyoming’s top fisheries biologists gathered in a makeshift laboratory on the banks of the Big Horn River with one goal on their minds: finding the best sauger in the state to participate in an experiment.

The fish weren’t willing participants.

“They’re a pissed-off fish,” said Joe Skorupski, fisheries biologist for the Wyoming Game and Fish Department. “They get angry when touched.”

But the goal was to make anglers fishing for the feisty, toothy, native fish happy. And the fish would get over it.

With urgency and precision, the team — led by Cody Region Fisheries Supervisor Sam Hochhalter, State Spawning Coordinator Kris Holmes and Skorupski — spent a week last month searching for 120,000 perfect sauger eggs to be rushed to one of the region’s top research universities.

Considering that a single female sauger can carry as many as 100,000 eggs, it doesn’t sound too difficult. But diversity is important in an experiment, so several females were needed. Working near Basin, the team’s goal was to find the top 10 females in a river teaming with sauger and deliver them to Colorado State University graduate student Dan Cammack.

“We want to give him the best of the best,” Skorupski said as a trophy-sized sauger was retrieved from the transport tank, dried and then carefully relieved of her eggs.

The middle third of her eggs — the best third — were used for the experiment.

Only 20,000 eggs are needed for the study. But since the eggs had to be collected with unimaginably difficult and limited timing — and if the team failed they’d have to wait an entire year to try again — they collected six times more eggs than needed as an insurance policy against failure.

To fertilize the eggs, 20 of the best males the team collected were milted. Samples were checked by microscope to ensure validity. Then the sperm and eggs were mixed with a turkey feather and cleaned with bentonite to avoid fungal infections caused by substrate and to prevent clumping, Holmes said.

As each fish was milted, Mark Komoroski, on his first field assignment with Game and Fish after working at a salmon hatchery in Idaho, got the privilege of gently releasing each fish back in the river. Each would have brought a smile to a happy fisherman.

“Size doesn’t matter. We need the fish closest to ripeness,” Skorupski said.

Some of the females were treated with hormones to bring them closer to spawning.

As soon as 60,000 fertilized eggs were gathered — more than 20 percent were lost to breakage and clumping in the process — they were moved in trays to a specially modified cooler, carefully strapped in Cammack’s vehicle and then rushed eight hours to the university. Temperature was important in this experiment.

Then the entire process was repeated.

Once Cammack got the eggs back to the lab, he tested the success of hatches at five separate water temperatures and one fluctuating temperature zone.

“Three of the six temperature treatments have already hatched,” Cammack said this week.

After all six have hatched, Cammack will look for larval deformities, make his report and then wait for the second part of the experiment to start. That may be harder than the capture, milting and rush back to the lab with the fertilized eggs.

“In the fall, we’ll collect adult sauger to try to make them ripen and spawn in the lab next spring,” he said. “It’s hard to make wild fish comfortable in the lab.”

Light and temperatures will be manipulated, but even more difficult might be matching the turbid conditions in which sauger like to spawn.

“The experiments will help us make informed decisions on how to protect this native fish,” Cammack said.

The experiment comes at a time of plenty for sauger in the Cody region.

“This is the most robust sauger population in the state,” Skorupski said.

Sauger naturally spawn in the turbid river during spring and then migrate north to Bighorn Lake. When the lake fills, the fishing picks up, but the best fishing for the tasty species is during the winter ice fishing season.

There have been three good years of recruitment, according to Skorupski. The Bighorn population is the slowest-growing, but they grow the largest, he said.

“The goal of the experiment is to determine how water temperature may be influencing the survival of early life stages of sauger. Ultimately, this information will help us better make management decisions for the sauger populations in the future,” Skorupski said.

The hope is to be able to better assist sauger during bad recruitment years — during drought, for example.

The experiment was suggested by Hochhalter and paid for by the Game and Fish Department.

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