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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Spring Valley Largemouth Bass Studied Catch One Of Reservoir’s Tagged Legal-Sized Bass And Earn $5

Charlie Powell Correspondent

Latah County’s Spring Valley Reservoir is home to some of the fastest growing largemouth bass in the northern tier, according to the latest electro-fishing survey.

Idaho Fish and Game Department workers in May shocked and tagged both legal and sub-legal largemouths. The study is called a multiple census mark and recapture study. When repeated in subsequent years, it will determine the population of bass in the 35-acre reservoir.

Legal-sized bass, those more than 12 inches, captured in the study were marked with white spaghetti tags placed near the dorsal fin.

Each tag bears a serial number and is worth $5 when returned to the department.

Sub-legal bass got blue tags that do not offer a reward.

“The reward tags will help us determine the number of legal-sized fish being removed each season,” said Ed Schriever, regional fisheries biologist.

In three nights of electrofishing, the researchers captured and tagged 62 legal-size bass in the reservoir, including one that stretched 20 1/2 inches.

Results from the late May survey estimated about 130 legal-sized fish inhabit the reservoir. But repeat studies will be required to get an accurate number.

In 1988, the year before bluegills were introduced, the largest bass that could be found in a similar survey of the lake was under 12 inches.

Spring Valley was known primarily as a hatchery rainbow trout fishery and was frequently planted with catchables and fingerlings.

Previous largemouth plants had exploded and stunted because the fish lacked a consistent prey base.

“In 1989 we introduced bluegills,”” said Clint Rand, the Fish and Game regional conservation officer in Moscow. “At that time we had bass in there that were only eight or nine inches long and were five years-old.”

Now, 2-year-old bass are measuring up to 9 inches.”

After the bluegills came a modest plant of tiger muskies, a sterile hybrid cross between a northern pike and a muskellunge. They foraged on the stunted bass providing a bottom-end selection.

Schriever believes there may be a couple of the tigers left in the impoundment. If so, they should be wall-hangers measuring maybe over 30 inches now.

The May survey showed about 7 percent of the largemouths in Spring Valley are more than 9 inches long while about 4 percent are more than 13 inches long.

Both Schriever and Rand acknowledge the cost of such success.

“We’ve essentially given up on planting rainbow fingerlings although we still plant lots of catchables and the trout fishery is still the most popular,” said Schriever. “There are more people starting to fish for bass.”

He said new management schemes may be proposed such as a slot limit. That would allow people to keep bass under 12 inches and over 16 inches only.

“But Spring Valley is only so big. We can only produce so many big largemouths.

Let’s say the population turns out to be 150 of those fish a year and our tag return in this study says anglers harvest 20 percent. That leaves 120 keeper fish to play with.

“How much fun can the public have with those fish? Is that what they want? In effect, the public has to decide where they want our efforts to go.”