Dennis Peirce: Coho time at Lake Oroville
There is only one place in California where you can fish for, and keep, silver salmon.
That is Lake Oroville.
The historic runs of silver or coho salmon are protected from angling due to their poor numbers. The only California river I know of with a significant run is the Trinity.
Some years good numbers of cohos can be found feeding off our coast but is against the rules to keep them. This past May there were large schools in Monterey Bay but their home rivers were in the Pacific Northwest.
It is a long story how these cohos have found their way into Lake Oroville.
Historically, the Feather River drainage has been host to the IHN fish virus. This virus affects king salmon and most trout species. It is naturally occurring in the Feather River but it is only a serious problem when fish are in high concentrations such as in a fish hatchery.
During the life of Oroville Dam, the Department of Water Resources has been committed to providing both a warm-water and a cold-water recreational fishery in the lake. In an effort to have a viable cold-water lake fishery and a successful king salmon fishery in the river below the dam a number of salmonid species have been tried in the lake.
Rainbow trout were planted and provided a good fishery in the 1970s, but were ultimately stopped because they were not providing an acceptable fishery by the late 1980s. King salmon and brown trout became the coldwater species of choice throughout the 1990s, but their ability to transmit the IHN virus resulted in a moratorium on stocking these species in 2001.
Coho salmon were found to be resistant to this disease, and are currently the only salmonid species allowed for stocking in Lake Oroville. Silver salmon were first planted in the 1970s but the problem has been a reliable source for these fish. There are no stocks available in the state due to the low numbers in our rivers.
The answer has been to bring in fertile eggs or live fish from Washington state. The Washington source for these coho salmon is a private aquaculture company. These fish have been selectively bred to mature in two years and even have the registered trademark of Domsea.
To transport fish across state lines there are a number of hurdles to clear including verifying that the fish are disease free.
In 2004, there were no coho available that met the criteria and none were planted in Lake Oroville. In 2005, the Department of Water Resources bought both eggs and live yearlings in the 6- to 9-inch size range. Most of the live fish were planted in the lake with a small group kept in the hatchery. The 2005 eggs were hatched and the fry have been raised in the Feather River Hatchery.
With an adequate food supply Domsea silver salmon can grow from the 6- to 9- inch size to 3 to 6 pounds in a year. This is what has happened over the last 12 months in Lake Oroville.
Hal McVey of Rough & Ready caught a 4.75 pounder in late October. The hatchery personnel achieved similar growth rates with the group of fish held over in the hatchery. They released 1,299 silver salmon into the lake this month weighing 3 to 5 pounds.
Now is the season for planting the fish hatched out from last year’s egg purchase. I spoke with Eric See, fisheries biologist for the DWR and he reports that during the month of November 170,000 yearling fish will be put into Lake Oroville. These fish were hatched from eggs in late January and have grown to the 8-inch size in 10 months.
Not many anglers pursue these salmon during the warm weather months. The fish are deep and scattered as is their food source, the Japanese Pond Smelt or Wakasagi. As the lake begins to cool the smelt congregate into large schools and locating these schools is one of the keys to finding the silver salmon.
Another tip for finding cohos in Oroville is to look for incoming water. Now that the rainy season has commenced, even the smaller creeks can attract the fish.
Depending on the season of the year, the smelt can range from 1 to 4 inches. Their coloration is white with ultra violet and blue highlights. There are a number of lures that imitate Oroville pond smelt, Kastmasters in chrome and blue, Speedy Shiners also in blue and chrome, Apex spoons with ultra violet hues and white trolling flies with the same purple/UV accent colors.
I like to try to mimic the food source but other anglers use a variety of lures and live minnows. One friend uses fillets of frozen bait fish on a hook. These silver salmon must be voracious feeders to put on weight as fast as they do, so a variety of minnow-imitating tackle will work.
In the last two weeks, the lake surface has dropped from 62 to 60 degrees. As the lake surface gets down into the mid-50s the salmon and the smelt will move higher in the water column. This current rainy weather pattern will accelerate the cool down.
If you go, a boat is a must to access the fish. Look for boat anglers off the face of the dam, a good spot to find cohos, Other anglers are the best indicators of where the fish are. The best angling for these silvers starts at Thanksgiving and continues through the winter months.
Denis Peirce writes a weekly fishing column for The Union and is host of “The KNCO Fishing & Outdoor Report,” which airs 6-7 p.m. Fridays and 5-6 a.m. Saturdays on 830-AM radio. He may be reached via e-mail at firstname.lastname@example.org.
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