A big fish story at Strawberry: New stocking technique showing tremendous success

Published: Wednesday, June 16 2010 5:00 p.m. MDT

Fish are examined under a ultraviolet light for dye planted in fish as part of a gill net survey with the Utah Division of Wildlife Resources June 2 at Strawberry Reservoir in Wasatch County.

Tom Smart, Deseret News

STRAWBERRY RESERVOIR — It is a fact, biologists tell us, that a fish can swallow another fish half its size. Meaning a 20-inch fish can swallow a 10-inch fish, with some difficulty.

But they don't. What fish choose to do is take smaller bites, a fact that brought about changes in the management plan at Utah's most popular fishing water.

In truth, said Alan Ward, project leader at Strawberry Reservoir for the Utah Division of Wildlife Resources, "We looked at more than a thousand prey fish pulled from the stomachs of other fish and found 98 percent were 7 inches or smaller. Only 2 percent were fish 8 inches or larger ... which is why we've started to plant fish that are 8 inches, and we're now seeing the results in our gill nets."

Earlier this month the wildlife agency completed its annual spring gill net sampling.

"The results are very encouraging," Ward said. "Our survival rate among cutthroats and rainbows is much higher."

Each spring and fall the DWR conducts netting surveys. Special nets are strung out in the late afternoon at established locations around the reservoir and are then pulled early the next morning.

Fish caught in the nets are identified, weighed and measured, and their stomachs are checked to help determine menu items.

In the past, fish planted in Strawberry were 7 inches or smaller and, biologists believe, were quickly eaten by larger fish and birds. As a result, gill net sampling showed very low survival rates.

After studying the dining habits of fish two years ago, the DWR decided to bump up the stocking size to 8 inches.

"What we found this spring was cutthroat numbers look good, if not better than last year. We also found good number of smaller cutthroat, which is the big story here," Ward said.

"We also found that rainbow numbers are getting better each year. Here, too, we're seeing much higher survival. Some of those rainbow we planted two years ago are already up to 17 and 18 inches."

After a treatment to remove all fish in 1990 because of high Utah chub numbers, it was decided that only fertile Bear Lake cutthroat, a formidable predator, kokanee salmon and sterile rainbow would be planted.

It was also decided that fishing regulations would protect the cutthroat but allow the catching of rainbow.

Today, fishing regulations at Strawberry allow anglers to catch and keep four trout and/or kokanee salmon. In that limit only two cutts can be under 15 inches and only one over 22 inches, and cutthroat between 15 and 22 inches must be released.

According to Ward, the responses to the new regulations and planting programs were immediate. Netting results in 2009 showed marked improvement in fish survival compared to 2006, 2007 and 2008, when sampling showed little, if any, survival.

In the first net pulled this spring, there were at least a half dozen rainbow in the 3- to 4-pound range and several cutthroat of similar size. In the second net, a deep-set net, there was a 5-pound cutthroat and at least a dozen rainbows and cutts in the 3- to 4-pound range.

All total, in the second of four nets, there were at least 75 fish, both large and small, and nearly as many crayfish. It took both Jeremy Christensen and Taylor Kimball of the DWR to lift the large tub holding the fish and net onto the roof of the boat and then to the back of the craft.

The first net, said Justin Robinson, project biologist, was set in the back of the Meadows area.

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