Mistakes of past nearly killed Lake Pend Oreille

Editor’s note: This is the first of a two-part series examining the decline of the fishing industry in Lake Pend Oreille. Today’s story details the causes of the decline. Part two will cover what is being done to mitigate the results, and the larger economic effect.

Lake Pend Oreille is dying. It isn’t dying from toxic waste or pollution, but economically. This pristine body of water, once the home of commercial fishing, is in a slump the experts are afraid may be irreversible. The death of this lake was caused by human interruption of the food chain. Re-intervention to try to right the wrongs of the past are in motion but hold only small hope for recovery.

In 1925, mackinaw, a long-lived char sometimes referred to as “lake trout,” were planted in Lake Pend Oreille and Priest Lake by the U.S. Fish Commission, later reformed as the U.S. Fish and Wildlife Commission. It was only the beginning. Landlocked sockeye salmon, locally referred to as kokanee, blueback or silvers, were flushed down the Clark Fork River from Flathead Lake in Montana during the regular spring floods of the day. In 1941, Idaho Fish and Game brought Gerrard rainbow trout, and later, in the 1960s, mysis shrimp from Kootenai Lake in British Columbia to Lake Pend Oreille.

It was believed at that time that Idaho needed trout capable of attaining record size and that mysis shrimp from Kootenai Lake offered a goodfood source for the troutThere was a problem: shrimp feed on the surface of the water at night and go deep during daylight. In Kootenai Lake, the West Arm being fairly shallow, this caused no problems, but in deeper Lake Pend Oreille, it did. Trout couldn’t reach the shrimp at the depths they sank to in 1,150-foot-deep Pend Oreille.

Chip Corsi, Region 1 supervisor for Idaho Fish and Game, said, “If we could take back the planting of mysis shrimp, we would.”

“Many mistakes were made back then due to lack of biological knowledge and unplanned consequences occurred.”

The biggest consequence? Mysis shrimp offered a huge food source for the deep-living mackinaw, and also whitefish, the largest species in terms of numbers in the lake, creating an explosion in their juvenile population. Mackinaw can live up to 20 or so years old, and Gerrard trout, 7 to 10. Trout, when about 16 inches long, start feeding on smaller fish. Prior to that they are basically insect-eaters. The ideal size from the mackinaw perspective, is the 1- to 2-year-old Kokanee fry. The larger the predator grows, the larger fish they consume. According to Fish and Game officials, 1- and 2-year-old kokanee are the chief victims in the food chain, being reduced by huge numbers by these larger fish.

After introduction in the 1940s, both kokanee and rainbow trout flourished in a sustainable pattern. In 1945-46 and after, the untouched fishery produced huge numbers of kokanee and the record rainbow of 37 pounds. The world-record Gerrard rainbow was caught in 1947 by Wes Hamlet.

At one time, Kokanee were fished commercially. Many old-timers remember their fathers hand-lining with jigs for washtubs full of 10- to 12-inch kokanee. Commercial fishing was finally closed in 1973, but the old smokehouse still stands sentinel at the south end of the Long Bridge in Sandpoint.

Meanwhile, the mysis shrimp were quietly reproducing at phenomenal rates, without, seemingly any natural enemies, at least those that could reach them. All was still well until 1952, when two new dams were built, Cabinet Gorge on the Clark Fork River in Montana and Albeni Falls on the Pend Oreille River at Priest River, Idaho. These two dams were the death knell for the Lake Pend Oreille fisherybut for different reasons.

The Cabinet Gorge Dam chopped off the river seven miles upstream, removing the 75 or 80 miles of upriver spawning habitat. After the Clark Fork ceased to be of use, only the strain of kokanee that had adapted to spawning in the lake shore gravels were left. Kokanee spawn in the late fall, usually late November, and early December. Granite Creek on the east side of Lake Pend Oreille and a few very small creeks were left, mostly too steep for fish to navigate.

Albeni Falls was the final nail in their coffin. During the 1960s, the Bonneville Power Administration managed to convince the U.S. Army Corps of Engineers, controllers of the dam, to radically lower the lake level, producing more flow for the Columbia River system and subsequently more winter power generation.

Corsi explained, “The destruction of 75 or 80 miles of spawning habitat up the Clark Fork River and its tributaries had a huge impact on the survival of the kokanee.”

That did it. Kokanee, the key food fish for larger fish began to disappear rapidly. They did this because in the beginning, Albeni Dam lowered the lake level, after the kokanee had spawned, thereby leaving redds or egg nests high and dry. Even then, everyone was still in denial. This practice continued until finally, in 1996, Idaho Fish and Game and the Corps of Engineers reached agreement to lower the lake prior to the kokanee spawn. Fish and Game Department closed fishing for kokanee altogether in 2000.

Avista ponied up large amounts of cash for mitigation, but it began to look like too little, too late. One such result of mitigation was that Idaho Fish and Game opened an office in Bayview nestled at the south end of the lake. The purpose of this office was to establish an unprecedented massive effort to recover the kokanee population. Hobart Jenkins of the task force, said, “Albeni Falls Dam destroyed the natural fluctuation of the lake, confusing future generations of kokanee as to how deep to spawn. This then became a huge problem when the Corps of Engineers started interrupting the cycle by unpredictable changes in water levels.”