By Tim Leeds
The Montana Department of Fish, Wildlife and Parks decided to take advantage of the low water at Fresno Reservoir to stock some new fish and now the water is high and muddy. But the opportunity is still there, FWP officials say.
"We saw this window and that's where we decided to try it," Kent Gilge, fisheries biologist at the Havre FWP office, said today.
FWP stocked Fresno with about 18,000 adult perch, about 160,000 rainbow trout and about 50,000 kokanee salmon, with more trout and salmon set to be added soon.
The drought decimated the population of northern pike and walleye, giving FWP an opportunity to temporarily stock trout and salmon as game fish, Gilge said. FWP is not starting a massive, long-term program, he said.
"This will be a very short window," Gilge said, adding that if the fish grow large enough that most pike and walleye won't be able to eat them, there will be about two or three years' worth of fishing the new species.
The muddiness of the water could be a problem for the fish if it lasted very long, Gilge said. Muddy water, which prevents light from filtering through the water, inhibits plankton production.
Plankton is the "main building block of life" in the reservoir, Gilge said. If it is reduced, the food chain is inhibited.
The level of Fresno is starting to slowly drop, and the inflow has dropped dramatically from where it was right after the five-day rainstorm and snowstorm this month that filled the reservoir, so the water should be clearing in the next few weeks, Gilge said.
Once the mud settles, rich nutrients from the sediment will remain in the water, providing a healthier environment for the fish.
The drought not only killed many of the trout's predators in Fresno, but it also helped provide a surplus of fish to plant there.
Low water levels around the state meant FWP couldn't stock as much fish elsewhere as it usually does. That created an excess of fish, which would have been shipped out of the state if they weren't planted in lakes like Fresno, Gilge said.
The population of walleye is down to about 15 percent of what it was four years ago in Fresno, and the remaining fish are relatively small.
While it's difficult to determine how many pike are in the reservoir, 104 fishermen angling for walleye at a recent two-day tournament only caught one pike, Gilge said.
The trout now planted in the reservoir were about 2 to 6 inches long, Gilge said. Some larger trout, about 8 or 9 inches, will be planted soon, he said.
The salmon, which could grow to about two pounds, were about 2 or 3 inches long when they were planted, Gilge said. About 50,000 more will be planted in a few weeks.
The trout and salmon planted this year will be the extent of the new stocking, Gilge said. He doesn't expect any extras to come out of hatcheries in Montana next year.
Outside of normal attrition, some fish may leave the reservoir through the spillway and gates. Gilge said that normally happens more in the spring and fall.
It will be impossible to tell how successful the stocking is until this fall, he added.
Fresno was originally stocked as a trout fishery after it was built by the federal Bureau of Reclamation as a flood-control and irrigation storage reservoir in the 1930s. Gilge said that continued through the 1940s and '50s, until northern pike were illegally introduced in the reservoir in the 1950s, and started eating the smaller fish.
"They just couldn't put enough trout in there," Gilge said.
FWP decided to try to manage Fresno as a northern and walleye fishery in the 1960s, Gilge said.
"That was kind of a death valve as far as the (trout) fishery goes," he added.
The loss of the trout in Fresno was what spurred the building of Bear Paw Lake by FWP as a trout fishery, Gilge said.