October 5, 1997

Studying Predatory Fish Takes Lot Of Guts

Rich Landers Outdoors Editor
 

Scientists are looking for anglers with a stomach for research on Lake Pend Oreille.

About 60 anglers already have boosted an Idaho Fish and Game Department and University of Idaho study on predator fish by saving the stomachs of rainbow trout, mackinaw and squawfish. The samples are saved on ice so researchers can inventory what the fish have been eating.

Some anglers have helped the study by tagging fish.

Even more anglers are assisting by reporting the numbers of tags on fish they catch.

The study seeks to understand why kokanee numbers are not stable in Lake Pend Oreille. While some researchers are concentrating on fluctuating water levels and the effects they have on kokanee spawning, Dmitri Vidergar is studying the impact of predators.

The UI researcher intends to:

Estimate the lake’s population of rainbows, lake trout and bull trout over 16 inches.

Determine how many fish are being consumed by these predatory fish, as well as squawfish.

Estimate how many kokanee are being consumed by predatory fish.

“One of the neat things about this research is that, while it’s designed for kokanee, it will give us a lot of valuable information about the predators,” said Vidergar. “Not much is known about Pend Oreille’s rainbows, lake and bull trout.”

The success of the research depends heavily on angler cooperation, regardless of whether the angler kills or releases his catch.

“The only possible way to tag the needed number of fish and obtain the required stomach samples is to work with fishermen,” Vidergar said.

Here’s how sportsmen can participate.

Learn to tag fish. Vidergar will teach serious anglers how to attach tags to any rainbows, lake trout or bull trout they catch at Pend Oreille.

Save the entire stomach tract of rainbows, lake trout or squawfish anglers decide to kill. (Remember, bull trout cannot be killed.) The samples must immediately be put on ice or in a refrigerator.

A label must be attached with the date of catch, species of fish and length of the fish from the tip of its nose to the shallowest fork in the tail. The samples can be dropped off at Harbor Marina in Garfield Bay or Holiday Shores in Hope. If that’s not possible, call Vidergar to make other arrangements.

Report the numbers on tagged fish that are caught. Even if you plan to release a fish sporting a red “spaghetti” tag on its back, record the five-digit number on the tag, measure the length of the fish to the fork in the tail and report this, along with the species, location and date caught.

“Anglers like the fact that we get back to them and give them information on the fish they caught and recorded,” Vidergar said. “We can tell them when and where the fish was tagged and how big it was at that time.”

Vidergar was on the lake daily through the summer. Now that school has started again, the graduate student returns to the lake only on weekends.

He said he’d like to get more tagged fish in the water before the Lake Pend Oreille Idaho Club’s fall fishing derby Nov. 22-30.

“That will be a prime time to get help from anglers,” he said.

, DataTimes ILLUSTRATION: Color Photo

MEMO: This sidebar appeared with the story:

Join a study

For more information on participating in fish studies at Lake Pend Oreille, contact researcher Dmitri Vidergar at Bayview, (208) 683-3054, or in Moscow at (208) 885-6434.

This sidebar appeared with the story: Join a study For more information on participating in fish studies at Lake Pend Oreille, contact researcher Dmitri Vidergar at Bayview, (208) 683-3054, or in Moscow at (208) 885-6434.

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