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From the Iowa DNR Website:
Fall Trout Spawn is Underway
By Joe Wilkinson
As autumn colors hit their peak, a fall show of another kind tells fisheries biologists that it is spawning season for Iowa brook trout. At the Manchester hatchery, hundreds of yellow ovals offset the dark olive coloration of each female brook trout ready to spawn. Yet they appear almost drab by comparison to males, with the pronounced body coloring enhanced by cream, black and white-edged fins.
The splashes of color are signs of the season. The hatchery holds brood trout for the yearly spawn. Following the brook trout run, now underway, come the brown trout within a few weeks...then the rainbows in December and January.
There’s natural spawning, of course, in some northeast Iowa streams. Most trout caught, though, are spawned under the eyes of hatchery workers at Manchester. Survival rates are hundreds of times higher; meeting the demand of 30,000 or so trout anglers who wade across nine northeast Iowa counties...and a growing number of urban fishing holes that support trout through the winter months.
“These are two-year old females; 14 inches, two to three pounds. Each one yields about 3,000 eggs,” explains Dave Marolf, Manchester hatchery manager as he tightens his grip on a slippery brood fish. By comparison, one three year old stretches to 16 inches and weighs four pounds; looking like a torpedo compared to the others.
Firmly stroking the undersides of the female trout, Marolf and Randy Mack direct streams of golden eggs into plastic bowls. Then, a couple male trout are used to add sperm. A saline solution is added, with a turkey feather used to stir the concoction. Within a couple minutes, the eggs are poured into an incubator tray, set under the constant, running water diverted from Spring Branch Creek, outside. In three weeks, the hatchery crew will go through the trays, siphoning off dead, unfertilized eggs. A couple weeks later, the viable eggs hatch as sac-fry.
“We spawn enough to produce about 100,000 brook trout,” says Marolf. “Most of them—50,000 to 60,000—will be stocked in 2010, as catchable, half-pound fish. Some will be stocked in 2009 as fingerlings. Most of the rest will be used to feed muskies produced at our Rathbun hatchery.”
However, this year’s floods leave a gap in 2009 brook trout stocking. Nearly all brook trout spawned last fall were washed away. “We had a few end up in the rainbow trout runs, but basically all of the brook trout that would have been catchable in 2009 were washed downstream,” says Marolf. Recovered rainbow trout and surplus rainbows from other agencies will fill the stocking schedules. There just won’t be any brookies next year.
With the brook trout spawn going strong, crews have corralled over 250 wild brown trout from French Creek, in Winneshiek County, for the next round of spawning. Then hatchery-raised rainbows will round out the spawning schedule. As eggs from the three species hatch, the fingerlings will be doled out to Iowa’s other two trout stations, near Elkader and Decorah, to be raised for future stocking.
TURN IN POACHERS!
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