Illegal Fish Introductions Rampant

By Beacon Staff

Fisheries manager Jim Vashro’s office wall is covered with pictures of fish, fish tails and a bumper sticker: “Kick the Bucket, stop illegal fish introductions.” Vashrow is updating Montana’s list of illegally introduced fish species, and the highest number are in Region 1 which stretches from the Flathead Indian Reservation north to the border of Glacier National Park.

“It just never quits,” says Vashro. “It’s so frustrating.” He’s looking at close to 50 new reports since his last count in February 2005.

Smallmouth bass have popped up in Flathead Lake. The Flathead Lake Biological Station has reported sightings, and Fish, Wildlife and Parks has confirmed one catch by a tribal biologist in Polson a few years ago. The smallmouth bass was reportedly quite large, making it likely the fish had been in the lake for some time.

“At this point,” says FWP biologist Mark Deleray, “it appears there’s been a few caught, but no evidence they’ve established in the lake.” Smallmouth bass are a game fish, but they compete with native cutthroat and juvenile bull trout, also sport fish, because they take over the shallow shores these two native species inhabit.

“It’s really rolling the dice,” Deleray says of the smallmouth bass presence, “because more likely than not it will be a negative impact.”

Before its negative effects on native species were fully realized, introducing fish was encouraged. FWP stocked rivers with sport and bait fish, and anglers partook in “bucket biology” – carrying live fish to new waters, or dumping live bait from one system into another. According to a 2004 report by University of Wyoming Professor Frank Rahel, since the turn of the 20th century, the number of authorized fish introductions across the country has steadily dropped while unauthorized introductions has risen.

In Region 1, mackinaw or lake trout were legally introduced into Flathead Lake in 1905, but did not inhabit Swan Lake. This past fall FWP netted nearly 200 lake trout ranging in size from 10 to 16 inches in Swan Lake. Lake trout compete with bull trout, and Swan Lake is one of the few waters where fishermen are allowed to keep caught bulls. Vashro says they don’t know if the lakers swam there, or were helped along the way. The old fish ladder at the Pacific Power and Light Dam in Bigfork was closed off years ago, making it unlikely lake trout swam from Flathead up the Swan River to Swan Lake.

Vashro cites Lion Lake, near Hungry Horse, as a poster child for the problems of illegally introduced fish. In 1992 FWP chemically treated the lake to get rid of pumpkinseed, yellow perch and brook trout. They then restocked the lake with rainbow and cutthroat. Vashro says the number of fishermen on the lake jumped from nearly zero to 3,000 in a year. However, they’re seeing yellow perch again, black crappie, and have confirmed the catch of one big white sucker. Now fishermen are reporting seeing less cutthroat.

“At some point we will probably have to poison again,” says Vashro. Deleray notes the concern raised by the introduction of white sucker: “They reproduce rapidly, and then they out-compete the more desired species.”

Vashro recently authorized the introduction of tiger muskie into Horseshoe Lake. He says it took seven years to study the effect it would have on other species, the water quality and possible economic consequences before they took the plunge and introduced it. The tiger muskie is used to control suckers and northern pikeminnows.

“People want diversity and we try to provide that,” Vashro says. Part of the goal of fisheries management is creating sport fisheries, he added, but his hands are often tied because of illegal introductions.

“We’re spending a tremendous amount of money just trying to recover fisheries,” says Vashro, who estimates the cost to recover a small lake at $20,000. He cites a 1992 incident of illegal introduction at Lake Mary Ronan. The would-be fish stocker was caught, and stuck with the bill for recovery: $800,000. Vashro estimates it would cost double that penalty today. Annually, his agency is spending $40,000 more per year on management, meaning it would need to sell 2,200 fishing licenses to cover just those costs.

Part of that cost comes from poisoning, like at Lion Lake, and restocking with native species and game fish. Poisoning also has its detractors.

This fall FWP treated two lakes in Jewel Basin with the poison rotenone. Black and Blackfoot lakes are part of the South Fork Flathead Drainage, and FWP intends to rid these lakes of hybrid trout and re-stock them with a pure strain of westslope cutthroat trout to protect the cutthroat downstream. FWP Commissioner Vic Workman voted against the poisoning of these lakes.

“I’ve got some reservations with the use of poisons because of some possible long-term effects,” Workman says. His main complaint is a lack of biology backing the poisoning in the South Fork Drainage. Workman hasn’t heard a satisfying estimate of how many hybrid trout have made their way into the Hungry Horse Reservoir, and questions whether the poisoning is necessary. He’s also concerned lakes will not be able to bounce back, and cites Whale Lake up in the North Fork as an example of a poisoned lake that hasn’t recovered.

“I can’t sell it to my public if I don’t have a good feel it’s going to accomplish something,” says Workman, “because the majority of the public loves those lakes the way they are.”

During the commission’s January meeting, Workman proposed suspending lake poisoning in Western Montana, but his motion was defeated 3-2. The commission will meet again in July for public comment and another look at the issue.

Vashro says in May of 2007 he counted 536 illegal introductions into 312 waters across the state, a total of 49 different species. Most of them were found here, in Region 1.

“We count, in this region, for almost half the illegal introductions in the state,” Vashro says. “We’ve got a lot of water, we’ve got a lot of fish, and we’ve got a lot of attitude.”

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