Kokanee numbers skyrocket in Lake Pend Oreille
Courtesy of IDAHO FISH & GAME A passel of Lake Pend Oreille Kokanee ranging in size from 7 to 9 inches are examined by Idaho Fish and Game, which says numbers of Kokanee are so high in the lake that it is adversely affecting size.
Courtesy of IDAHO FISH & GAME Numbers of kokanee in Lake Pend Oreille have fluctuated over the years, but most recently numbers are likely as high as in the 1970s when catching a lot of small fish was the rule. Lake trout suppression in LPO began in 2006, which may be one factor for an increase, while a crash i mysis shrimp numbers was another, according to IDFG.
Kokanee numbers in Lake Pend Oreille are at record highs.
That doesn’t mean, however, that fishing is good for the small, blue back salmon.
Lake Pend Oreille Kokanee have for the past couple years hovered around 8 inches in size. The bigger ones have pushed 9 inches while a huge portion of the burgeoning population is too small to catch.
Matt Corsi, fishery manager on Lake Pend Oreille where biologists are gathering data to build models to project future populations, said a threshold exists for the landlocked salmon. If they don’t exceed a certain size — usually around 8 inches, they are difficult to catch using the usual methods that include attractors and spinners with a daisy chain of double hooks.
“You kind of have to have a certain size before they become available to anglers,” Corsi said.
Kokanee size is density dependant. That means, under normal conditions, having fewer fish in the lake results in larger fish. But a few factors including a sudden decline in Lake Pend Oreille of the mysis shrimp that compete for plankton with kokanee fry, and the suppression of lake trout, Corsi said, have given kokanee populations a jolt.
During trawl surveys last year, the nets trawlers used to catch kokanee to measure populations strained under the weight, and number of fish.
“We broke the record for the number of fish we had in a trawl net haul,” Corsi said. “We broke the record three times last year.”
Numbers equal what they were in the 1970s when anglers caught sacks of the small fish for the smoker, but anglers these days prefer bigger fish.
“It’s kind of a cultural shift,” said fishing guide Chad Landrum.
Maybe because of the sheer numbers, the Kamloop rainbow catch rate far exceeded what it had in years past, Landrum said. And other species including walleye have also hit record size and catch rates.
The abundance of the small salmon churns the engine of the lake’s fishery, he said.
The sentiment is spread across the board. Game fish in Pend Oreille rely on kokanee as a food source. The greater the source food, the more species can feed on the Kokanee and grow.
“Kokanee is what keeps the machine going,” Corsi said.