March 22, 2001
Contact: Madonna Luers, 509-456-4073
Tucannon loses 80,000 rainbows to trichodina; southeast Washington trout stocking reduced
About 80,000 catchable-size rainbow trout, destined for release this spring into southeast Washington fishing lakes, have died from an external parasite outbreak at the Tucannon Fish Hatchery in Columbia County.
The outbreak of "trichodina" started in early March in a three-acre earthen rearing pond at the hatchery. Trichodina is a ciliated external protozoan commonly found on the skin and mucous of fish raised on surface water. It does not typically cause mass losses of fish and it is not a health risk to humans.
Washington Department of Fish and Wildlife (WDFW) hatchery workers quickly began a formalin treatment of the fish in the pond, but the parasite persevered, even at higher dosages, and fish continued to die.
Formalin is the "drug of choice" to treat the parasite, explained WDFW fish health manager Kevin Amos, but rainbow trout are more sensitive to it than salmon. "It's sometimes a fine line between which is killed by formalin first, the fish or the parasite, " he said.
Pond size, water flow, and low seasonal water temperatures made treatment challenging, Amos said. Last week hatchery crews started a treatment with potassium permanganate and finally stopped the spread of the parasite. Unfortunately 80,000 fish died as a result of the protozoan outbreak. Other fish exposed but recovering will not be stocked out until they are healthy.
The loss means trout stocking plans for southeast waters had to be changed, said WDFW regional fish program manager John Whalen. Twenty thousand catchable-size trout from WDFW's Ford hatchery will help fill the gap, but southeast waters will receive approximately 62,000 fewer eight-to-nine-inch size trout this year.
The table shown below reflects what had been planned for southeast waters, and what is now being stocked. Fishing waters scheduled to receive triploid trout later this spring will be receiving their original allotments of the one-to-1-1/2-pound fish, including Bennington Lake (2000, with 1200 donated by Tri-State Steelheaders Club), Quarry Pond (400), Golf Course Pond (300), and West Evans Pond (300). The stocking numbers in the following table include these triploids.
|Name of Lake||Planned Allotment||Stocking Allotment|
|Asotin County |
|Golf Course Pond||20,600||15,100|
|West Evans Pond||21,200||15,200|
|Columbia County |
|Dayton Juvenile Pond||3,100||3,100|
|Deer Lake|| 3,000||2,000|
|Garfield County |
|Whitman County |
|Rock Lake||12,000 Rainbow trout|
5,000 Brown trout
|Stocked out of Ford Hatchery|
|Union Flat Creek||1,500 Rainbow out of Spokane||1,500|
|Walla Walla County |
|Bennington Lake||2,000 triploid trout||2,000|
|College Place Pond||3,200||3,200|
|Fish Hook Pond||6,100||5,100|
|Jefferson Park Pond||2,100||2,100|
|Franklin County |
|Adams County |
In addition, during the first week of March WDFW released about 50,000 surplus juvenile steelhead trout into two waters in southeast Washington. Dalton Lake in Franklin County received 31,406 juvenile steelhead trout (4-6 inches in length) and Quarry Pond in Walla Walla County received 18,864. These fish, which are an anadromous form of rainbow trout, were excess Wallowa stock steelhead from Lyons Ferry Hatchery, and were not needed to meet steelhead program goals. The Wallowa River steelhead stock is being phased out of Washington's Snake River steelhead program because they do not meet National Marine Fisheries Service (NMFS) criteria for recovering threatened steelhead. These supplemental fish were stocked into Dalton Lake and Quarry Pond to provide additional angling opportunity above the planned allotment of catchable trout for these waters.