Sunday,  July 2,  2002

By Torli. McCormick
Special to the Star Tribune
OSAGE, MINN.

     Wading in
knee-high water as clear as moonshine, Dave Schaum strips out 3 feet of fly line and begins a series of rhythm-gathering false casts. His eyes are transfixed on a pool 20 feet ahead.
     ”Did you see the back on that guy?” said Schaum, pointing to the boil in the water, the handiwork of the rising brown trout. “I’ll  tell you what, that’s a big fish . . .  
. . better than 20 inches, I bet.”
     It’s
just shy of 9:30 p.m. last Thursday. The gloaming has nearly given way to nightfall. Nature’s little flashbulbs – fireflies - flicker and refract off the moving water. All is perfect, except for the maddening din of dozens of blood-sucking mosquitoes.
The presence of large mayflies entices the
Straight River ’s big
brown trout to abandon their traditional hiding
places to feed on the
surface. And incredible fly fishing is sometimes the result.
    
For Schaum, 37, of Osage, the night isn’t over --it’s just beginning. And he’s giddy with anticipation, given last night’s exploits. “I caught three browns over 20 inches last night,” said the full-time science teacher and summer fishing guide. “We’ll see what happens tonight. Maybe well catch Walter.”
     In
two weeks in mid-June and early July, Schaum, as well as a small but hard-core contingent of fly fishers, descend on the Straight River to fish one of the Midwest’s most storied mayfly hatches— the Hex.
     Hexagenia limbata is the largest
North American mayfly, and its emergence, particularly on the Straight River , has been likened to an aquatic blizzard. The presence of so many large mayflies --  in the air and on the water -- entices the river’s big brown trout to abandon their traditional hiding places to feed on the surface. In turn, the dry fly fishing can be second to none.

Blizzard hatches

“The intensity of the hatch is different every year, but there’s always the chance that you’re going to hook up with a big, big fish,” Schaum said. “I’ve seen some true blizzard hatches over the years where there are so many flies. . . that fishing is nearly futile due to the plethora of naturals.”.

Mayfly hatch makes fishing good

     The Hex hatch presents fly anglers with myriad challenges. The hatch is relatively short -- about 90 minutes, often less. And most of it happens in the dark. Stream wading and navigation can be difficult, even dangerous. And even the most accomplished fly fisher, Schaum says, can come unglued under the cover of darkness.
     “Hearing is extremely important for locating fish in the dark, especially on cloudy nights with no moon,” Schaum said. “Sight is still important for locating individual fish, however, and a ripple or two is alI that is needed to pinpoint the source of the feeding sound.
     “But at times you’re pretty much fishing blind, although with practice it’s possible to become very accurate at casting merely to the sound of a feeding fish, and at setting the hook by sound, too.”
Overtime, Schaum says he’s developed a “sixth sense” about fishing the nighttime Hex hatch. It takes patience and time and ingenuity.
     “With more experience at fly fishing in the dark comes a sort of feel for how it’s done,” he said. “How much line is needed to reach a feeding fish? And how do you determine what the various currents are doing to your line and fly? Those are questions that are only learned with time on the water.”


Water warms
Schaum, who started fishing the river as a teenager, spends much f his summer break on the river; he knows every riffle, pool, bend and feeding lie. The middle-school teacher also has become a well-spoken student of the watershed’s ecological health.
     “Years ago, the Straight had a viable brook trout fishery,” said Schaum, a member of Trout Unlimited and TU’s  Straight River Trust Committee
(SRTC), an advocacy group formed three years ago to help with stream improvements. “But intensive logging practices--
like the beavers are trying to do out here today— degraded the habitat, warmed the water and killed the brookies. But because the river is fed with dozens of cold, clear springs, the brown trout population, which can tolerate warmer water to a point, has survived.”
     The river’s “thermally marginal” water temperature, which can fluctuate dramatically throughout the day, is a source of concern, said Doug Kingsley, DNR fisheries supervisor in Park Rapids.
     “I think it’s on the bubble,” Kingsley said, referring to the Straight River as a trout fishery. “Water temperatures are right at the upper limits where even brown trout can survive. Some stretches warm to more than 70 degrees during the
day, at which point the fish have to find thermal refuges such as deep pools and other places where it’s cooler.”
     That makes managing the Straight River watershed a complex task, and places DNR officials in the middle of a  vexing dilemma.
     On one hand, the Straight River is a rare northern Minnesota trout fishery, and considered by many fly fishers as one of the best in the Midwest . It’s also a year-round destination for birders and waterfowl hunters in the fall. On the other hand, the 15-mile-long watershed, rich in sandy soil, is heavily irrigated for agricultural production --
production that contributes scores of jobs to the region.


Wells on increase
The largest consumer of water in the region, the R.D. Offutt Co., grows hundreds of acres of irrigated potatoes and employs as many as 600 people, according to R.D. Offutt manager Larry Monico.
    The company also runs a potato processing plant near the river, which uses additional water from the Straight River basin .
    The chief concern, say Schaum and other Straight River advocates, is pinning down the relationship between the river’s groundwater supply and its stream flow. If      more wells are approved by the DNR, they ask, will the increased irrigation reduce the river’s stream flow, raise the water temperature and kill the trout?
     “It’s a real concern. For much of the 1990s, we’ve had above-average precipitation around here,” Schaum said. “But we will hit a another drought cycle, and I’m worried that
the increased irrigation, coupled with the lack of rain, could really  impact on the stream and the trout.”

While there is anecdotal evidence suggesting irrigations wells can take water away from the small springs that feed the stream, DNR studies have shown no conclusive evidence that permanent harm is being done to the groundwater supply or the fishery, said Bob Merritt, area hydrologist with the DNR division of waters, which administers irrigation well permits.

“Our (study) model is not showing there’s substantial increases in water temperature,” he said. “What we’ve learned, at least up until now, is that the fishery is under similar condition… even prior to the irrigation.” Merritt says more research is needed. But research is expensive and labor-intensive. “The problem is that we’re stretched too think (in the division of waters) on other projects and don’t have the funds right now,” he said. “I fish the Straight River quite a bit, and I’m the last person who wants to see anything bad happen to it. I want to do what’s best for all parties concerned up here.

Ron Miller, a pediatrician from Fargo , N.D. , has fly-fished the Straight River for more than 20 years. He is also the chairperson for the Straight River Committee and a member of Trout Unlimited, one of the groups that sued the state a decade ago seeking greater protection for the river. “I want a permanent moratorium on all irrigation permits on the Straight River , as well as have the DNR develop a management plan for the fishery,” he said. “You can’t keep approving irrigation wells forever without ruining the river. This is an impending crisis, and the division of waters needs to act. “The whole thing makes you wonder if the division of waters sees the river as a water resource exclusively for agricultural.” DNR officials say they support a Straight River management plan. “I’m hopeful we can get something before too long,” Kingsley said. By 11 p.m. last Thursday, Schaum had done his level best to coax a big brown to eat one of his jumbo-sized Hex imitations. He fished upstream and downstream, and switched patters countless times. Still nothing. What’s more, the fabled Hexegnia limbata mayfly was a no-show. “The hatch is pretty much winding down,” Schaum concluded. “It didn’t help that the fish were really spooky tonight, either. Still, to me, nothing is more uniquely rewarding as fishing the Hex hatch on this beautiful river. I hope that never changes.”