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MailTribune.com
  • Feeding Frenzy

    Annual stonefly hatch means Rogue River's rainbow trout hear the dinner bell ringing
  • TRAIL — For a short window of time Tuesday, Chris Gross found himself in trout-bum heaven.
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    • Salmonfly Facts
      Fly-fishers throughout the Western United States annually look forward to the storied hatch of the stonefly, or salmonfly.
      Known scientifically as Pteronarcys californica, they are the largest o...
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      Salmonfly Facts
      Fly-fishers throughout the Western United States annually look forward to the storied hatch of the stonefly, or salmonfly.

      Known scientifically as Pteronarcys californica, they are the largest of the stoneflies in the Pacific Northwest and gained their nickname because they hatch during the spring chinook salmon run in Pacific coastal streams such as the Rogue River.

      Adult stoneflies sport long, scaly bodies, ant-like legs, large wings and a plated, turret-like head. They measure 1 to 21Ā"2 inches long, and males are about an inch shorter than the females. Males sport forked-bar genitalia that protrude off their abdomens and curl onto their backs.

      They are most commonly found in fast-moving, shallow rivers with softball-sized stones exposed to the sun, and the upper Rogue River provides perfect stonefly habitat.

      Their presence, however, can be disrupted. An Oregon Department of Fish and Wildlife habitat report for the North Fork of the Rogue River states that stoneflies easily can be lost from a stream system where scouring and re-sorting of substrates is high and retention of "coarse particulate organic matter" is low.

      The stonefly's life cycle lasts about four years. Virtually their entire lives are spent as submerged nymphs, with less than two weeks as mature, flying adults.

      Entomologists say their final cycle begins in the spring when the river temperature warms to about 55 degrees, triggering maturing nymphs to crawl from their rocky havens toward the river's edge.

      When they emerge, the nymphs crawl under rocks or brush, where they shed their skeletons and emerge as fully mature adults.

      When their wings dry, they climb onto foliage and mate, with the males dying a few days later.

      The females then fly over the water, dropping or laying their eggs on the surface at dusk, triggering feeding frenzies for the fish below.

      — Mark Freeman
  • TRAIL — For a short window of time Tuesday, Chris Gross found himself in trout-bum heaven.
    Cast after cast, his fat, imitation salmonfly would belly-flop onto the surface of the Rogue River's famed "Holy Water" impoundment, acting like a dinner bell to the rainbow trout below.
    Thinking this 2-inch-long fly was the real McCoy, the rainbows darted after it like it was another of the free, double-cheeseburger-like salmonflies they'd been gorging on all morning. But this one had something sharper than cheese in it, and the tug-o-war that fly-fishers live for was on.
    "For a bit, it was fantastic," Gross says. "I probably raised 30 fish and landed 10 or 11 of them, and it was all in 45 minutes. Then it was over."
    This is the magic of the salmonfly hatch, a combination of massive flights of macro-bugs and bingeing rainbows that turn steelheaders into trout bums for one magical month on the upper Rogue.
    Salmonflies now plying the skies over the far upper Rogue are the biggest of the water-born insects here, and their annual hatch triggers a feeding frenzy in the Rogue basin's trout waters that is unmatched by any other hatch.
    It's all about casting huge, orange-bodied, dry flies among the rafts of real flies up to 21/2; inches long that are floating on the surface. They're the largest of the stoneflies revered by fly-fishers in Western states and go by the nickname salmonfly because they hatch in the midst of the spring chinook return in rivers such as the Rogue.
    They hatch after the winter steelhead run but before the Rogue's summer steelhead show up in good numbers, mainly when water temperatures hit 55 degrees.
    Their timing makes them a perfect bridge for steelheaders segueing from one addiction to another. They're also a hatch of choice for the myopic trout-lovers who relish a change from casting tiny dry flies or nymphs.
    Cast them for resident rainbows throughout the Applegate River. Smallmouth bass eat them from the surface of Lost Creek Lake just upstream of the dam. A few resident trout as far up as Union Creek will mouth them, too.
    Eagle Point fly-fishing guide Dave Roberts casts them exclusively from his driftboat this month on the upper Rogue near Eagle Point for native cutthroat trout, rainbows and even early-run summer steelhead — all of which can't pass up what appears to be a free meal.
    "I've had seven (summer) steelhead come to hand this past week, plus big cutthroat," Roberts says. "The trick is locating the fish and dodging the salmon fishermen."
    And nowhere is that better than the "Holy Water" impoundment, a .8-mile stretch between the base of Lost Creek Dam and Cole Rivers Hatchery. It's Oregon's only river stretch where hatchery trout are stocked strictly for catch-and-release angling with barbless flies and only traditional fly gear.
    It also is the salmonfly's Mecca.
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