On Tuesday, fisheries biologist Scott Stanton was electrofishing Bruneau Dunes State Park’s Big Lake and pulling up four gill nets that soaked there overnight. Doug Megargle, back at the Idaho Department of Fish and Game’s Jerome office, was hoping Stanton would catch a big fat zero.
“Hopefully he’ll come home today pulling nothing but empty nets,” said Megargle, Fish and Game’s regional fishery manager.
Finding any carp in Big Lake would be an expensive disappointment.
A beloved fishery in the 1980s, Big Lake became overrun by common carp and for years hasn’t been able to produce the trophy bass that anglers loved.
What’s wrong with carp? The fast-growing nuisance fish explodes in numbers, gobbles up the food needed by game fish species and muddies the water by rooting for vegetation on the lake bottom. That blocks sunlight and hinders plankton growth. It’s devastating to a bass and bluegill fishery.
So in late October, two planes flew over Big Lake, dropping 480 gallons of rotenone in long, low strokes. That, park and fishery managers hoped, was the end of the carp invasion.
But they couldn’t know until now. Sometimes a few carp manage to find refuge from the fish-killing chemical and survive.
On Wednesday morning, I called back. Megargle got right to the point.
“It’s good news, and there are no carp,” he said. In fact, Stanton caught no fish of any kind. “So that greenlights us for beginning transplant probably in about a month.”
To rebuild a bass and bluegill fishery, he and Stanton need a good forage base (the bluegill) before bringing in the predator (the bass). So this year, they’ll stock only bluegill taken from a southeast Idaho reservoir.
“We want them to get through one good spawn before we introduce bass,” Megargle said.
Fish and Game isn’t likely to prohibit fishing at Big Lake during the rebuilding, he said. But it will try to educate anglers on the necessity for productive bluegill spawning — probably through a sign encouraging anglers to release what they catch there or to harvest conservatively.
“We’re excited that the people are excited to see this fishery reclaimed … but remind people that it doesn’t happen overnight,” Megargle said. “It takes a few years to build the fishery back up.”
The water in Big Lake looks crystal-clear right now — dramatically improved water quality is typical after carp removal — but that won’t last. Decomposition of all those carp carcasses is continuing, releasing nutrients into the water, and may lead to significant algae blooms this summer, he warned. That effect could take a couple of years to run its course.
A tip for budget-conscious explorers: Craters of the Moon National Monument is offering free admission on Saturday and Sunday, in honor of National Park Week. And yes, the monument’s Loop Road is open again to vehicle traffic after spending the winter as a snow trail.