Depending on who you ask, walleye are either born and bred in Montana or they are interlopers, a predatory fish poised to upset local ecosystems.
As it stands, Montana Fish, Wildlife and Parks (FWP) says the fish is not native to the state and is subsequently not managed as a native species. Walleyes Unlimited, a non-profit organization with a mission to enhance the waters of Montana, would like to see walleye reconsidered as a native species, but if nothing else, at least managed the same as other game fish.
Executive director and member for almost 20 years, Bob Gilbert, said the species gets a bad rap. Whenever other fish numbers decline, “it’s always the walleyes fault,” he said.
FWP officials said that as a top predator, walleye have strong potential to affect existing fisheries through competition for forage fish and direct predation on sport fishes.
Some people refer to walleye as “wall-eyed pike,” though they are not related to pike.
A member of the perch family, walleye are skilled predators and highly adaptable. In ideal conditions, walleye are known to live upwards of 20 years. According to FWP, the walleye record for Montana was caught in the Tiber Reservoir and weighed 17.75 pounds.
FWP’s 2016 report on the ecology and management of walleye in Montana declared that “The walleye is not native to Montana; their natural range is from Canada (east of the Continental Divide) south to Louisiana, and from the Dakotas east to the Appalachian Mountains.”
Despite state and federal agencies, like FWP and U.S. Geological Survey, listing walleye as non-native, Walleyes Unlimited remains dogged in its determination to see the fish treated as any other native to the waters of Montana.
“It makes you want to put on your fighting shoes and go kick some butt,” Gilbert said. “But that’s not the way to solve problem. It takes compromise.”
In an effort to have FWP reconsider the classification status of walleye, the group petitioned the state Fish and Wildlife Commission in Helena last December. The nonprofit, joined by several walleye anglers, asked the commission to weigh evidence from researchers, mostly in Canada, that verify the native and introduced distribution of walleye in western states.
Looking at the information that is available to FWP, officials delved into museum collections, historical records, stocking history and primary peer-reviewed literature.
FWP Native Species Coordinator, Zach Shattuck, said, “In reviewing all the available information and really trying to take as deep as a dive as we could, there was nothing that brought us to any conclusive evidence to suggest that walleye are native to Montana prior to European settlement.”
Walleye in Montana have been documented since 1933, when U.S. Geological Survey staff recorded the first catch of a walleye. That same year, over 300,000 walleye were stocked in the Missouri River, according to FWP. Another 400,000 walleye were stocked in 1934.
Studying the genetics of walleye, fish biologists believe that Montana’s population of walleye did not originate and evolve here, but rather were introduced. The closest known native population of walleye is in eastern North Dakota.
“To kind of a paraphrase Sir Issac Newton, ‘We’re standing on the shoulders of giants,’ meaning that a lot of this information has been conducted and it’s a matter of putting it all together to formulate this contemporary understanding,” Shattuck said.
Piecing together the evidence, FWP officials believe walleye could not migrate into Montana, in part, because of the last ice age. During the Pleistocene Epoch period, a massive ice sheet covered the Hi-Line and the Missouri River in eastern Montana and the Dakotas. When it receded — almost 11,700 years ago — a glacial silt settled in the Missouri River. The silt was later described by settlers in the early 1800s as, “The Big Muddy.”
“You start to see a different river as you get into parts of North Dakota and South Dakota then we have up here,” Shattuck said. “It’s a big, connected river but there is a gradient of suitable habitat that may have precluded walleye from establishing in Montana.”
Shattuck said that the Missouri River, prior to our anthropogenic modification of the river basin, was one of the most turbid rivers in the country.
“Further down the basin into Nebraska and Missouri it’s incredible to look at the bluff to bluff expanse of the flood plain and what that river once was,” said Shattuck. “Reading a lot of the historical accounts, it was a pretty tough environment to live in.”
What significance does “The Big Muddy” play? Fish biologists say that while species such as sauger, blue sucker, catfish and sturgeon thrive in silt, walleye do better in clearer water. In other words, not conditions found in the Missouri River.
According to Gilbert, FWP largely based its classification decision from the records of the Lewis and Clark Expedition that occurred between 1804 and 1806.
Looking at historic fish surveys from the expedition, records show that the Corps of Discovery encountered sauger — a close cousin of walleye — as they navigated Montana, but did not log any walleye. Sauger is considered native to the Missouri and Yellowstone drainages. The likeness between sauger and walleye is enough that the two fish can interbreed with the hybrid known as “saugeye.”
Gilbert said it’s possible that Lewis and Clark and their crew caught walleye but assumed they were sauger.
“There are paddlefish, which are native, in the Missouri too, but Lewis and Clark didn’t see any of those either,” said Gilbert.
Gilbert said that in order to change the listing of walleye to native, FWP needs definitive proof, such as a skeleton or fossil that they can confirm originated in Montana.
“Maybe we’ll never be able to prove it according to FWP guidelines,” said Gilbert.
Around the Libby area, the closest place to fish for walleye is in the Noxon Reservoir, where they were illegally introduced. A stone’s throw away from the reservoir, at Upper Thompson Lake, FWP biologists discovered a pair of walleye in October.
Gilbert said that it’s curious only two were found. “My inquiring mind would like to know, how did that happen?” he asked.
Gilbert’s guess is that a bucket biologist — someone who brings their preferred species of fish from one lake to another that may be more convenient or closer to home — is to blame given the small number found.
FWP Fisheries Biologist, Brian Stephen’s said, “The two walleye discovered in upper Thompson lake are almost certainly the result of bucket biology.”
Due to the high number of easily accessible lakes, Stephens said bucket biology is extremely common in northwest Montana.
Given the excellent trout fishing in western Montana waters, FWP has been cautious in its approach to introducing an effective predator like walleye, but recognize the upsides.
Officials said potential benefits associated with introduction of walleye are the diversification of angling opportunities and the increased economic activity that might come with it.
“In certain places, we absolutely enjoy them,” said Shattuck. “They are an important species for the state as far as providing recreation.”
FWP officials estimate that walleyes consume around 750,000 pounds of perch in Canyon Ferry each year. That equates to approximately four pounds of perch per walleye.
Shattuck said FWP stocks walleye in a number of waters, including Fort Peck which is a world-renowned walleye fishing hub.
Some anglers have asked FWP to stock walleye west of the continental divide, but fishery biologists are apprehensive that the fish could be transferred to other waters and irrevocably damage westslope cutthroat trout and other native species.
That’s fine by Gilbert and Walleyes Unlimited. Recognizing the different fishing culture in western Montana, Gilbert said, “We don’t want walleye west of the divide.”