Fort Peck Fishery

The Water is Up and Peck is Back

When water filled Fort Peck last year and flooded its shorelines, a storehouse of nutrients washed into the reservoir. That triggered an ecological chain reaction, creating some of the best fishing in years for walleye, northern pike, smallmouth bass, and other species. By Andrew McKean

This story is featured in Montana Outdoors May-June 2012 issue

When fishing is good on Fort Peck, it seems like every wind-blasted point and slick-shale shoreline holds a hungry walleye.

But when fishing is slow on the sprawling northeastern Montana impoundment, anglers are left wondering: How can so much water seem so appallingly empty?

Like grain prices and weather in this wide-open land of extremes, fishing on Fort Peck tends toward the generous or the stingy.

You can predict walleye and northern pike activity with a fair degree of reliability just by looking at the reservoir’s water level. When it’s so low that hundreds of feet of exposed gumbo shoreline separates the sagebrush prairie from the gray-green water, chances are the bite will be off (I’ll explain why in a minute). But when Fort Peck’s full pool starts lapping the tops of boat ramps and water inundates bays grown over with cottonwood saplings and salt cedar, it’s time to hook up your boat, stock up on minnows and leeches, and head to Montana’s most underutilized fishery.

That time is right now.

Fort Peck’s current high water level—and the diverse fishery it supports—justifies a trip this summer. Local anglers are saying, “Peck’s back,” and they prove it with photos of heavy stringers posted on tackle shop walls and Facebook pages. It’s not just walleye on those stringers either, but also smallmouth bass, northern pike, catfish, and even unexpected species like freshwater drum and crappies.

Best and worst of times
Though often called a lake, Fort Peck is technically a reservoir, impounding the Missouri River with an earthen dam that was the world’s largest when completed in 1935. The reservoir was built to hold melted snowpack gushing into the river from surrounding plains and the Rocky Mountains. That annual spring torrent flooded farmland and washed out towns across the region until Depression-era WPA workers built the dam.

Though the reservoir’s water levels have risen and fallen widely over the past 70-plus years, the most extreme fluctuations occurred recently. Fort Peck set an all-time elevation record in June 2011, storing so much water from record prairie rain and snowpack, combined with above-normal mountain snow­melt, that it ran out of room. During just a few months the reservoir gained 14 vertical feet, or enough water to fill a second Canyon Ferry Reservoir, Montana’s second-largest impoundment. As a result, the U.S. Army Corps of Engineers released a record amount of water through the power turbines below Fort Peck Dam and an even greater volume over the lake’s emergency spillway directly into the Missouri River.

The rise in 2011 was especially incredible considering it came after years of drought and reservoir drawdowns that left Fort Peck at a record-low elevation in 2007, just four years previous. “We’ve seen the worst of times and the best of times in a surprisingly short window,” says Steve Dalbey, Montana Fish, Wildlife & Parks regional fisheries manager in Glasgow. “And the way the fishery responded to high water last summer and this year confirms that the manipulation of Fort Peck’s water level is the most important fisheries management tool in the entire tool box.”

It’s also the most exasperating. That’s because the Corps operates Fort Peck Dam as part of a hydrologic system extending from Montana down the Missouri River to St. Louis. The federal agency adjusts the capacity in all reservoirs along the river to balance such competing interests as barge traffic, flood control, irrigation, and sport fishing.

In other words, the Corps, not FWP, controls Fort Peck’s most important fisheries management tool.

The up-and-down effect
Because Fort Peck’s surrounding landscape is less fertile than what’s found in states to the east, the water has fewer nutrients, says FWP reservoir biologist Heath Headley. Fort Peck can’t produce the same biomass of fish per acre as, for instance, Ohio’s portion of Lake Erie or Minnesota’s Mille Lacs Lake. But Fort Peck can receive an important influx of nutrients if water levels rise and fall at the right times. It has to do with shoreline vegetation.

Ideally, says Headley, the Corps would gradually draw the reservoir down several feet beginning in late summer and leave it there for a year or two, allowing shoreline vegetation to take root and grow. “Then the best thing would be to raise the water level several feet in March every couple of years,” he says.

That would do two things. First, the well-established shoreline vegetation would provide a massive nutrient boost, kicking the reservoir’s food chain into high gear. When water levels rise, shoreline plants drown and then decompose. The decayed matter provides food for zooplankton and other micro­organisms at the base of the food chain. Newly hatched walleye and other fish species eat zooplankton. So do aquatic insects. Minnows eat the insects, and predator fish such as walleye and pike eat the minnows.

Second, water raised in early spring corresponds with the yellow perch and northern pike spawn. Those species lay their eggs on sturdy underwater structures, such as submerged sagebrush. “If the reservoir elevation comes too late in spring, then perch and pike have already finished spawning, and their spawn isn’t nearly as successful as it could be,” Headley says.

Unfortunately, the drought starting in the early 2000s caused the reservoir’s water level to drop and kept it low for years. Fort Peck marinas looked like ghost towns, and boat ramps sat stranded hundreds of yards from the water’s edge. Vegetation grew on shore, but it never flooded. The low water also exposed large expanses of gravel and rock that during most years are critical spawning and rearing areas for several fish species.

The drought years were anomalies, but even in normal water years the reservoir’s water levels are often tough on fisheries, says Headley. Each summer the Corps lowers Fort Peck to provide water for downstream users. Then, the following spring—usually too late to benefit perch and pike—it allows the reservoir to fill up again with runoff, only to open the floodgates a few months later to send the stored water downstream. “That constant up and down in lake elevation makes the varial zone [periodically inundated shoreline] unproductive for vegetation,” Headley says. Shoreline plants can’t take root, he explains, when they get drowned twice a year.

The most recent drought now behind them, Headley and Dalbey are celebrating the high water lapping Fort Peck’s shoreline. The reservoir’s water levels were raised incrementally in 2008, ’09, and ’10, “just like we wanted,” Dalbey says. Then came the floods of 2011, filling the reservoir to its brim.
Dalbey explains that incremental water level increases bring in a new crop of nutrients gradually over a period of years, rather than all at once. “Think of shoreline vegetation as ‘fertilizer’ for the reservoir,” he explains. “If you use it all up in one year, with too much of a water level rise, then you’ve got nothing left over. But if you can draw that ‘fertilization’ out over several years, the net benefits to the reservoir are much greater.”

The benefits to anglers are greater too. The revitalized reservoir ecosystem produces more and healthier fish. And much of the renewed ecological activity occurs near shore, making game fish more accessible to anglers.

Up to a point. Dalbey is quick to note that high water is always great for fish, but not always for fishermen. “After a few years of good forage production, there’s a tipping point, when there’s so much natural food in the system that walleye and other predator species start ignoring bait and lures and can be tough to catch,” he says. “When walleye growth rates are at their highest, angler catch rates are often at their lowest.”

The latest water cycle has proved to Dalbey and Headley that the pace and pattern of water fluctuations is critical to maintaining Fort Peck’s high standard of fishing—even more so than the number of walleye stocked by the department or the number of fish that anglers keep.

Stock, yes, but what size?
Others aren’t so certain. Like many Fort Peck walleye anglers, Steve Harada is as much interested in stocking levels as he is in water levels. The former state president of Walleyes Unlimited credits the current fishing bonanza mostly to the walleye hatched and raised at the Fort Peck Hatchery and stocked several years ago. “We’ve had a good year or two of fishing, but I don’t think Fort Peck has reached its full potential,” says Harada, who helped lead the effort to build the $26 million fish-rearing facility. “If the hatchery could produce walleye to its full capacity, I think the strong fishing could continue.”

Headley and Dalbey agree that the hatchery is critical to maintaining Fort Peck’s renowned walleye fishery. But exactly what number and size of walleye should be stocked is still open to debate. The hatchery produces both walleye fingerlings and mosquito-sized fry. An argument for stocking fingerlings is they are bigger and more likely to survive. “One problem is that it’s costly to raise them to that size,” Dalbey says. Even though fry survival is much lower (because the fish are tinier and more vulnerable), FWP can stock far more of the newly hatched fish for a given amount of money. If environmental conditions are right, as they have been the past few years, large numbers of fry will end up growing large enough to bite angler’s lures.

Then again, some years it may make more sense to stock fingerlings. “The problem is no one knows what effect stocking has on Fort Peck’s walleye population, or when it makes sense to stock fingerlings versus fry,” says Dalbey. FWP has recently begun a four-year study to find out. “Stocking is definitely critical, but to make the best use of license dollars we want to find the right mix of planting fry and fingerlings,” he says.

All this talk about walleye reflects the importance of Sander vitreus on the big lake. Though Fort Peck has a dozen other species capable of producing great fishing—the reservoir holds seven current state fish records—it’s the glassy-eyed walleye that drives angler interest and FWP management priorities. Headley says he devotes roughly 85 percent of his time to walleye management, despite a dozen other species arguably in greater need of attention.

Keeping close watch on these other species is Jim Schultz. The Fort Peck angler has fished the big reservoir for three decades, and he says when the angling is hot, it’s among the best fishing waters in the country. “In terms of numbers of fish and size of big fish, it’s off the charts,” says Schultz. “And not just walleye. There’s great fishing for northern pike, smallmouth bass, lake trout, and salmon.”
Headley agrees. “Right now is the time to take advantage of good water conditions and great fishing on Fort Peck. We are in the high arc of a water cycle,” he says. The biologist knows that by next year increased forage abundance will lower angler catch rates. Also, another drought will no doubt be back, and with it lower lake levels and fish numbers. “When the dry times return, we won’t have the sort of abundance we’re seeing in pretty much every game fish that swims in this reservoir,” he says.Bear bullet

In 2011 FWP completed a ten-year management plan for Fort Peck’s fisheries. It provides a road map for FWP biologists as they manage the lake’s diverse fish species. The plan is based on input from anglers, businesses, and staff of other state and federal agencies, as well as detailed analysis of the reservoir’s ecological conditions. “It incorporates local concerns, our goals, and what the reservoir can and can’t biologically produce,” says FWP biologist Heath Headley. “It then maps out stocking levels, lake level management recommendations, and other things we do to manage these species.” 
Read the plan by visiting the fwp website at and searching for “Fort Peck.”

Andrew McKean is editor of Outdoor Life. He lives outside Glasgow, about a half-hour drive from Fort Peck Reservoir.