Suppression of walleye a hot-button issue

According to Montana Fish, Wildlife and Parks Region 1 Supervisor Jim Satterfield, if approved, an effort will be undertaken to reduce the population of walleye in the Noxon Reservoir in the spring. Due to the predatory nature and prodigious spawning habits of the walleye, the population of other native fish species has seen a decline in recent years. The effort will involve techniques to prevent damage to fish species such as Bull Trout and other salmonids.
Walleye are not native to Montana and their presence is believed to be the result of an illegal introduction.
Satterfield said, “The walleye is an unauthorized species. It is a recent addition and not compatible with the ecosystem. The walleye is an aggressive predator and is having a negative impact on native salmonids.” Salmonids are a family of fish that includes trout, salmon and whitefishes.
Methods to reduce the walleye population will include gillnetting, trap netting and electro fishing. Electro fishing uses electricity to stun fish before capture and is a common scientific method used to sample fish populations.
Trap netting uses a wire mesh device that fish swim into but cannot escape.
Gillnetting is the method with the most potential for capturing unintended species or by-catch, however, fisheries biologist for FWP Kenneth Breidinger believes the impact on the environment will be negligible.
“We are designing our methods to minimize negative environmental effects,” said Breidinger.
According to Breidinger, there are also economic reasons to undergo an effort to reduce the walleye population in the Noxon Reservoir. The Noxon Reservoir is the fifth most popular fishing destination in region 1, including seven bass tournaments per year and a popular wintertime perch fishery. The FWP believe that the walleye is a threat to populations of fish that anglers come to the reservoir to catch.
The environmental assessment undertaken by the MFWP cited an example of another reservoir that experimented with walleye introduction and as a result, had to pay approximately $130,000 per year to boost the rainbow trout stock depleted by the walleye. The walleye has also been known to threaten perch population. Perch is a popular game fish for anglers.
“Walleye have been known to destroy other fisheries and recovery efforts to revive the bull trout population have been disrupted by them”, said Breidinger.
While there has been some dispute over the proposed program to reduce walleye from fishermen who enjoy catching them, Satterfield believes fishing is not sufficient to control the population.
“There are a lot of people who enjoy catching walleye but you can rarely affect population levels by fishing alone,” said Satterfield.
Breidinger said the program would be a dual effort: to reduce the adult population and to interrupt the spawning cycle of the walleye. A large female can lay up to 500,000 eggs. After 40-60 days, juvenile walleye begin to feed on native fish such as perch as well as depleting zooplankton, a necessary dietary staple for other fish.
“We hope to not only suppress the adult population but to also disrupt the spawn. If we can eliminate the source, then we can prevent further introductions,” said Breidinger.
FWP hosted an open meeting to answer questions about the environmental assessment at the Thompson Falls Rural Fire Department on Highway 200 on Tues. March 19 from 4 p.m. to 7p.m. While verbal comment was not collected, the public was encouraged to submit written comment. The environmental assessment to investigate suppression of walleye in Noxon Reservoir can be read online at www.fwp.mt.gov or a hard copy can be attained at the FWP offices in Kalispell, Helena or Thompson Falls.