Salmonfly Time in Montana – if You’re Brave Enough

High water on Montana’s Big Hole River. There is usually about 10 feet of clearance under this bridge.

Sometimes there’s nothing like opening up a fish’s tummy to find out what they’re eating. You may find surprises.

A couple weeks ago, when my son, Kevin, and I kept some North Dakota pike for dinner, we checked stomach contents to see what the fish had been eating. One pike had inch-long fish in its belly. That was no surprise, as pike love to eat other fish. Another fish, however, had white stringy-looking aquatic worms of some kind in its stomach. There have been other times when we’ve caught pike full of crayfish. We’ve also caught pike with bellies full of scuds, or what many think of as freshwater shrimp.

All of which demonstrates that northern pike are opportunistic feeders and there isn’t much in a pike’s neighborhood that they won’t eat, including baby muskrats and ducklings.

I seldom keep trout for dinner, so I usually don’t get that kind of information from trout I catch. Still, when I have a streamside chat with another angler it’s a good idea to pay attention when they provide post mortem information. A few weeks ago when camping on the Madison River, an angler from another campsite volunteered that he’d kept a couple fish, including a rainbow trout with a belly-full of salmonfly nymphs.

That was important news, a sign that salmon-flies, those stoneflies on steroids, were getting active in preparation for the annual transformation when Pteronarcys californica, or giant stonefly, leaves its home on the bottom of western rivers to crawl out of the water. Once out of the water, the insect climbs up streamside vegetation, such as willows or other brush, crawls out of its exoskeleton and emerge as a flying winged insect.

Fish feed on stonefly nymphs on a year-around basis, of course, as nymphs lose their grip on rocks and get picked off by alert fish. This time of year, however, those opportunities increase as nymphs migrate towards river shorelines, followed by trout in search of these big bites of protein.

The salmonfly emergence happens on many western rivers, though it’s not totally predictable just when those first nymphs will emerge from runoff-swollen rivers in search of a new identity and a literally once-in-a-lifetime opportunity to…shall we say, get lucky. Those female insects that don’t fall back into the river or get eaten by birds, and manage to mate, end their life cycle by flying back over the river to lay eggs along the water’s surface to start the next generation of giant stoneflies. It’s a cycle that has gone on for millions of years.

It’s an old tradition that on the Big Hole River, the salmonfly hatch begins on or about June 13, or Miners Union Day in Butte. On the other hand I’ve spotted adult salmon-flies on the Big Hole as early as Memorial Day and as late as the first week of July.

Just guessing, but this year the hatch will likely run late because of the cold spring we’ve had, as the hatch is triggered by a complex combination of water temperature and hours of daylight, or at least that’s how I understood the explanation that now-retired state fisheries biologist Dick Oswald gave me some years ago.

Another question is whether the Big Hole and other rivers with salmonfly hatches will be fishable when the big bugs emerge. Last week the amount of water rushing down the Big Hole River almost doubled to around 10,000 cubic feet per second as rains cut into the heavy mountain snowpack. There will, no doubt, be anglers out there floating the river during the high water, but for average boaters it’s downright dangerous in current conditions.

Still, the natural process continues and salmon-flies are emerging somewhere. In checking around I came across the website for Rock Creek Fisherman’s Mercantile, a flyshop near the mouth of Rock Creek. The shop reports the river is a roaring, chocolate torrent of water as it nears its confluence with the Clark Fork River. Still, salmon-flies were spotted on streamside bushes, preparing for the propagation of the species.

Life goes on, even if we’re not fishing.

The State of the Fishery in Southest Montana

The lower Ruby River – runoff still on hold

Heavy snow falling outside reinforced a fact we already knew: 2011 is going to be another good water year. It also reinforced the reports Montana Fish, Wildlife & Parks fisheries biologists made at last week’s annual George Grant Chapter of Trout Unlimited State of the Fisheries meeting.

If there was a common theme in the reports it was that after several years of healthy water flows on the area’s premier trout waters, fish populations are responding in terms of both numbers and quality. Here’s a brief rundown on the biologists’ reports.

Matt Jaeger reports that Clark Canyon Reservoir is poised for great fishing after several down years following extremely low pool levels in 2000 – 2005. The reservoir is now at full pool, and approaching flood levels this spring. There are numbers of trophy-class fish in the lake and fish stocks are being replenished by natural reproduction in feeder streams in addition to hatchery stocking.

After a number of years with sharply reduced winter flows from the Clark Canyon Dam, which had a significant negative impact on fish populations, Jaeger is hoping stronger stream flows will help rebuild the fishery. He’s also optimistic that stronger flows may blow out some sediment deposits from a tributary, Clark Canyon Creek. The outlook for 2011 is good.

Jaeger reported Poindexter Slough, the spring creek on the outskirts of Dillon, much of it on state land, has serious sediment problems and he hopes to divert some Beaverhead River flow to blow some sediment out. Still, Poindexter has incredible fish populations and is a real fish factory.

Travis Horton, Fisheries Manager for FWP Region 3, reports that rainbow trout numbers in the Jefferson River are up as a result of continuing good water flows and brown trout populations are stable.

Horton talked at some length about northern pike. Pike moved up the Missouri River from Canyon Ferry Reservoir and are now established in the river’s reservoir above Toston Dam. Biologists have found pike in the Gallatin and Jefferson Rivers, including upstream from Whitehall. Obviously, that means it’s entirely feasible for pike to next move into the lower Big Hole and threaten the Big Hole’s blue ribbon trout fishery.

Grayling recovery specialist Jim Magee reports that long-term projects are finally beginning to show some results in upper Big Hole tributaries. He also notes they have documented natural grayling reproduction in the upper Ruby River for the last two years.

Jim Olsen reported on a 2009 study estimating a total of 77,579 angler days on the Big Hole River. The majority, 43,199, were residents and 34,381 non-residents. While that’s a lot of fishing pressure, it’s nowhere near the Madison River, with 173,339 angler days, making it Montana’s most heavily fished river.

Olsen reported on 2010 shocking surveys on the Big Hole, indicating the highest trout densities, some 2,500 per mile, are in the Jerry Creek section of the river, in contrast to 1,500 per mile in the Melrose and Hogback areas. The Pennington Bridge area has the lowest trout numbers, with just 500 per mile. Olsen attributes the low numbers to poor spawning habitat in the lower river, though there is good adult fish habitat. Those fish counts don’t count juvenile fish (under 10 inches) or whitefish, which he notes, “are still the most abundant fish in the river.”

Olsen also notes that while the fish populations in the Jerry Creek area are high, the size of fish is smaller than in the lower river, indicating that fish populations are at or above carrying capacity, and “anglers shouldn’t worry about keeping and eating some of those fish.”

The last two years, FWP has been tagging trout in the Big Hole and early reports from anglers indicate that some fish are real travelers. An example is the 16-inch rainbow trout first tagged in 2009 in the Hogback area. An angler caught and released the fish on March 22, 2010 in the Hogback area. A little more than a month later, on April 26, 2010, another angler caught that same fish near the East Bank area some 50 miles upstream. That’s a tourist!