Nevada Focus: Assembly line fertilizes trout eggs by the thousands

MARLETTE LAKE - More than three-quarters of a million trout are headed for streams, lakes and reservoirs throughout Nevada, but anglers have plenty of time to tie their flies. Right now, the fish are still just eggs.

In an assembly line operation on the banks of this secluded lake high in the Sierra Nevada, hundreds of trout are unceremoniously stripped of their eggs and sperm to start another chapter in the ongoing story of restocking the state's waterways.

''We're doing a good thing for the fish and for the fishermen as well,'' said Dave Sanger, staff fisheries biologist for the Nevada Division of Wildlife. ''It's a lot of fun. It's labor intensive, but we want to provide a quality trout.''

Marlette Lake, just to the east of its more famous and far more accessible alpine cousin, Lake Tahoe, is home to the brood stock of cutthroat and rainbow trout as well as the hardy and feisty Tahoe rainbow introduced in 1984.

Except for the occasional government vehicle, the locked gates leading to Marlette keep out the motorized public. Those who see the lake get there on foot, by bicycle or on horseback.

The road - more a broad path - is steep in spots and deeply rutted. The 3-mile ride from the gate to the lake took more than 30 minutes.

Fishing is strictly forbidden in Marlette, where volunteers net the fish and lug them in 5-gallon buckets to holding ponds. There, they are separated by sex to await the moment of surrogate parenthood.

A tiny needle attached to an air hose is injected into the female fish's ovaries and a burst of air forces out the eggs - 800, more or less, for each pound of fish. The semen from the males is hand-squeezed from the milt glands.

Some fertilizing operations also hand-squeeze the roe out of the females, but as rough as the method used at +Marlette+ looks, it actually is less stressful for the fish, according to wildlife spokesman Chris Healy.

''If having kids was this easy, everybody would be doing it,'' he said.

Still, the tuckered trout spend a few minutes in the classic belly-up position before getting their wits together enough to begin wiggling around the holding pond to await release back into the lake. About 4 percent don't make it.

They also are measured and checked for tags to determine their history in Marlette.

Healy said only about 5 percent ever venture back to that end of the lake to spawn.

''Why? We don't know.''

The eggs and the sperm are mixed together. After fertilization takes place, they're rinsed off and prepared for transport to hatcheries around the state where they'll develop into fry and grow into fingerlings before being released into the wild.

This year's goal is 850,000 fertilized eggs, Sanger said.

Marlette was purchased by the state in the early 1960s and has been used as a home for brood stock ever since, yielding more than 17 million trout eggs.

Thirty fish paid the ultimate price to assure a healthy hatch. Sanger dissected them and removed a piece of the spleen and kidney from each. The organ fragments were put on ice and shipped overnight to the U.S. Fish and Wildlife Service hatchery in Anderson, Calif., south of Redding, where they will be analyzed.

Sanger said the organs represent key parts of the blood-filtering system. A sample of ovarian fluid from each female also is tested to ensure a disease-free stock.

About 200 fish experienced their dissection in a far more rustic method the day before Sanger performed his.

The local bear population has discovered the captive audience of free eats. Despite an electrified fence surrounding the holding ponds, the bears had a buffet that trimmed the number of males to about 400.

''I guess you don't mind getting zapped if you're hungry enough,'' Sanger said.


On the Net: Nevada Division of Wildlife's Web site:


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