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Not counting out kokanee
Fish on road to recovery after Missionary Ridge Fire
Herald Staff Writer
Photo by Jerry McBride/Herald
Click image to enlarge
Photo by JERRY McBRIDE/Herald photos
Colorado Division of Wildlife staff and volunteers collect kokanee salmon Monday in Grimes Creek below the fish weir placed in the river to keep the salmon from swimming upstream to spawn.
Photo by JERRY McBRIDE/Herald photos
Colorado Division of Wildlife staff and volunteers collect kokanee salmon Monday in Grimes Creek below the fish weir placed in the river to keep the salmon from swimming upstream to spawn.
Photo by JERRY McBRIDE/Herald photos
Beri Blair, a veterinarian technician, collects tissue samples from kokanee salmon Monday in Grimes Creek above Vallecito Reservoir for an annual health check.
Kokanee salmon are making a comeback in Vallecito Reservoir after ash and mud from the Missionary Ridge Fire suffocated them nearly six years ago.
The salmon received an annual health inspection Monday in Grimes Creek, a tributary north of Vallecito Reservoir.
For the exam, about 60 fish were captured and beheaded by state Division of Wildlife workers to be tested for whirling disease. Biologists also took kidney and ovarian fluid samples to check for bacterial and viral diseases. The test results won't be known for several weeks.
"It's just kind of a control thing and trying to keep our fish population healthy so we can all go out and fish and enjoy," said Beri Blair, one of only two sample collectors in the state. "You just always want to keep tabs on your population."
The Division of Wildlife also collected eggs from the females and sperm, or milt, from the males to spawn a new batch of kokanee at the fish hatchery in Durango. About 400,000 fingerlings will be released in April with about 10 percent surviving to adulthood, said DOW Fisheries Biologist Jim White.
The average length of fish being captured Monday was 15 inches, which is a couple of inches shorter than in previous years, which means there is a larger population of kokanee in the reservoir, White said.
"The numbers of kokanee are definitely up from what we've seen four or five years ago," White said.
In 2002, ash and debris from the Missionary Ridge Fire flowed into the reservoir. At the same time, the reservoir was low and the water was warmer than normal. The ash and debris settled on the reservoir floor, cutting off an important supply of oxygen to the cold-water kokanee. This caused the fish to rise to warmer waters levels, eventually killing them.
Kokanee are native to the Pacific Northwest, not Colorado, which is why every year the DOW has to nurture a new batch in the Durango Fish Hatchery. Only about 20 percent of the kokanee spawn naturally in the streams above Vallecito Reservoir. Fish biologists said the elevation and cold water prevent kokanee from surviving on their own in Colorado. The DOW has been stocking Vallecito Reservoir with kokanee for more than 40 years.
A health inspection is necessary to ensure new diseases aren't present or transferred to other reservoirs and streams.
Kokanee are good for Vallecito Reservoir because they are nonpredatory - they eat plankton - and they provide a good food source for the reservoir's pikes, rainbows and brown trout, White said. They're also highly sought after by fisherman. Because kokanee don't eat other fish, they don't have a mercury buildup like predatory fish.
To capture the fish, the DOW installed a fish weir in the stream to block the kokanee's migration. Hundreds of kokanee can be seen this week spawning in the water just north of the reservoir in Grimes Creek. The area is off limits to fishermen until Nov. 15.
Electric probes are used to catch the fish. The fish have an involuntary movement toward the probes, which shocks them and causes them to go belly-up.
"It's a fatal attraction; they come right up," White said.
The fish are either 3 or 4 years old when they decide to go upstream, spawn and die.
Health inspections and fertilizing will be done in other locations across the state, including the Dolores River above McPhee Reservoir.
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