STRAWBERRY RESERVOIR — There was a question a dozen years ago over whether or not the Bear Lake cutthroat could successful play the role of "predators of the deep."

That is, could they eat enough chubs to stop them from overpopulating the reservoir?

For several years it appeared they were dining out regularly. Then, surveys showed a ballooning population of chubs in the reservoir. The total weight or biomass of chubs in the fish population in spring and fall gillnet samples jumped from 6 percent to 24 percent between 1997 and 2001.

The reason, it was determined, was that fishermen were catching and keeping too many of the big cutts. There were too few diners to feast on the overabundant food supply.

In response, new regulations were put in place last January limiting the number of big cutts anglers could keep.

New figures released recently by the Utah Division of Wildlife Resources show a definite increase in the number of the larger Bear Lake cutthroats and a lower number of chubs.

"Which proves to us," said Alan Ward, DWR fisheries biologist at the reservoir, "that the new regulations are working."

Back in the 1980s, chubs did, in fact, overrun the reservoir. Gillnet surveys showed that for every trout in the reservoir there were nine chubs. Chubs are sometimes referred to as a "trash" fish because no one wants them. In 1990, the reservoir was chemically treated and all the fish were killed.

Replanted were Bear Lake cutthroats, the predator, and sterile rainbow, theoretically the catch-and-keep fish. Instead, for some unexplainable reason, Strawberry attracted the keepers. From Strawberry, nearly half of the fish caught are kept, where in other reservoirs the catch-and-return rate is nearly 75 percent.

In June and October, said Ward, a routine sampling of 16 sites showed:

An increase of 152 percent in the number of cutthroats over 20 inches. Surveys have shown that larger cutts are more likely to prey exclusively on fish and that nearly 50 percent of all cutts over 20 inches feed on fish.

The new regulations bumped the size of the cutts anglers could keep from 18 to those over 22 inches.

Ward said the new regulations "have met or exceeded expectations of increasing the adult population of cutthroats by 45 percent from 2002."

Along with the increase in the average size of the cutts, there was also a noticeable increase in the incidence of predation on nongame fish from 17 percent to more than 20 percent.

This has led to a 34 percent decrease in the number of chubs caught in fall gillnets and a 10 percent drop in the weight of chubs in the biomass. Included in this is a 61 percent drop in the one-year-old chubs, the primary prey of cutts, in the sampling.

Along with the drop in chub numbers, there was also a decline in another prey base, the redside shiner, of 73 percent.

"The one thing we can attribute this to," said Ward, "is the new regulations. We did see more chubs and shiners in the stomachs of the cutts than we've seen in the past, and this is due to the fact that the average size of the cutts is larger."

Strawberry is Utah's most popular fishing spot. It registered more than 1.5 million hours of fishing pleasure in 2001.

Earlier this year, fishing pressure was down.

Ward attributed the decrease to the new regulations and slow fishing.

"As some of the larger fish started to show up, fishing pressure increased," he noted. "People began to catch more and larger fish. I received a number of comments from people telling me they'd never seen the cutthroats look so healthy nor had they seen so many big cutthroats."

The Bear Lake cutthroat, noted for its taste, will never eliminate the nongame fish from Strawberry, but in sufficient numbers it has the appetite to impact the population to where it will be unable to overrun the reservoir and push game fish out as happened in the 1980s.

Starting last January, anglers were allowed two cutthroats under 15 inches and only one cutthroat over 22 inches within a four-fish aggregate limit, which can include cutthroat, rainbow and kokanee salmon.


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