For the Love of Fish
Fish traps and ladders at Cabinet Gorge
For thousands of years, Dolly Varden trout swam freely throughout what came to be called the Cabinet Gorge. They were once sea-going trout. Much like salmon, they returned to spawn in the fresh water habitat they began life in. Their travels were impeded neither by nature nor by man. Nature struck first.
Scientists speculate that an ice age occurred, lasting until twelve thousand years ago. A giant glacier formed, plugging up rivers throughout the Northwest. Separated by an impenetrable wall of ice, the Dolly Vardens on both sides of the ice wall continued on their evolutionary journey. They did not evolve in an identical manner.
Biologists tell us that all species are continually evolving and adapting to their environment. Distinct features within a specie that provide the biggest advantages for finding food; for protection; for reproduction; move forward in time. These advantageous features, possessed by a subset of the species, eventually evolve to become a general characteristic of the entire specie. The characteristics become a part of the specie because the members of the specie possessing the characteristic survive, reproduce, and pass along the trait. This adaptation concept forms the basis for Evolutionary Theory.
The Dolly Vardens on the east side of the ice wall found a freshwater environment different from that which their cousins to the west swam in. Undoubtedly, some Dolly Vardens on the east side of the ice wall possessed characteristics distinct from the rest of the fish population. These characteristics were favorable to the new environment the ice wall created. These characteristics gave the Dolly Vardens that possessed them an advantage over the other fish. The characteristics allowed this subset of Dolly Vardens to survive, to reproduce, and to evolve the population into something other than what it was.
The Dolly Vardens on the west side of the ice wall were unable to return to many of their freshwater spawning grounds. The Dolly Vardens on the east side of the ice wall were landlocked, unable to continue on with their journey to the sea. They evolved into a fresh water fish. And they underwent changes in their skeletons and in their DNA, the building block of all living things. The Dolly Vardens evolved into a new species, which we now call Bull Trout.
Eventually, the ice glacier melted and the landscape was forever changed. And fish populations on both sides of the ice wall swam amongst each other again. This time, however, they swam as Dolly Vardens and as Bull Trout. Separated by the barrier of Evolution, they were now distinct species.
Fifty years ago, a new barrier emerged in the form of man-made dams on the Clark Fork River. The Bull Trout were separated, unable to freely swim in their native habitat. And they were unable to return to their native spawning grounds. Stressed by man-made habitat alterations and pollution in the form of mining waste, sewage, agricultural runoff, and erosion from logging and construction, the number of Bull Trout plummeted. They became a Threatened Specie- i.e., a species now facing the threat of extinction.
Avista Corporation is licensed to run the Cabinet Gorge and Noxon Rapids Dams on the mighty Clark Fork River. Both dams interfere with the spawning of the native Bull Trout. According to Rich Russell, a Water Resources Specialist with the Dept of Natural Resources and Conservation, Avista Corporation is trying to mitigate the damage to the Bull Trout through the building of fish traps. The fish traps catch the Bull Trout as they migrate upstream. The trapped fish are then netted and driven by truck around the dams. Once released, they are free to continue on with their upriver migration. There is no other way for the fish to travel upriver. Similar to the ice glacier, the dams are an impenetrable barrier to the fish.
The fish trap and ladder at the Cabinet Gorge Fish Hatchery dam was built in 1991 as an aid for Kokanee salmon. For the last three years, it has also been used to safely trap Bull Trout. Last year 68 Bull Trout were trapped and netted. This year the total numbers are not in yet. However, 35 fish have so far been transported over Cabinet Gorge Dam. Trapped fish are weighed, measured, and implanted with tracking devices. They are released upstream in Bull River Bay, a popular recreational area just west of Noxon. Of those trapped this year, at least eight fish went up the river and spawned. A number of fish hung around the mouth of Rock Creek, unable to navigate the Creek due to low water level. Three fish turned around and successfully swam down through the dam’s turbines. There is still no safe passage corridor for fish attempting to swim downriver. The turbines are a dangerous gauntlet they must run.
Unlike salmon, Bull Trout do not die after spawning. Those that live will attempt to spawn again next year. Many will attempt to winter in Lake Pend Oreille. That means a downriver swim through the turbines of the dams. Some may decide to stay in Cabinet Gorge Reservoir. And, because they have a strong homing instinct, it means an upriver truck ride around the dams during spawning season.
Joe DosSantos is the Avista employee in charge of their fisheries program. Possessing a Masters Degree in Fish and Wildlife Management, he has been working with fisheries in western Montana for over 20 years. According to DosSantos, Avista applied for a water use permit in March of 2001 to build a fish trap downstream of the Noxon Rapids Dam. They anticipate approval of the permit any day now.
The permit was needed to divert the water of a spring area that enters into the Clark Fork River just below Noxon Rapids Dam. They found the river water in that area much cooler than the surrounding river, due to the influence of the spring area. Bull Trout favor cooler water. Therefore Avista plans to divert 4,000 gallons a minute of water from the spring area into cisterns that form the basis of the fish traps. The Bull Trout will follow the cooler water straight into the new fish ladder and trap.
The Noxon Rapids Dam fish trap is scheduled for completion sometime in year 2002. It is hoped that it will enable the return of a strong Bull Trout population in the Clark Fork River tributaries of Martin Creek, Vermilion River, Graves Creek and Prospect Creek. Most of these creeks are located around the town of Trout Creek, and all are downstream from Thompson Falls.
According to DosSantos, no local, above-ground streams will be impacted by the water diversion. The estimated cost for the spring development and the new fish ladder and trap will be one half million dollars. The costs will eventually be absorbed by the rates paid by Avista customers, who are primarily located in northern Idaho and eastern Washington.
DosSantos explained that the fish traps are a pro-active approach on Avista’s part to open up the Bull Trout’s migration corridor. Avista has made a commitment to help the Bull Trout for the next 45 years. That’s about a decade less than the dams have already impacted the Bull Trout’s migration corridor. When queried about the odds of this fish surviving another 45 years, DosSantos admitted that they are breaking new ground, and that the project is experimental in nature. He also added that it’s a long-term plan because, “You don’t restore natural resources overnight. It takes a while.”
For additional information, contact Rich Russell at 406-752-2288 or Joe DosSantos at 406- 847-2729.