Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake; Effects of Operation of Kerr and Hungry Horse Dam on Reproductive Success, 1983 Annual Report.

Koktneesalmon (Oncorhvnchusnerka), the land-locked form of sockeye salmon, were originally introduced to Flathead Lake in 1916. My 1933, kokanee had become established in the lake and provided a popular summer trolling fishery as well as a fall snagging fishery in shoreline areas. Presently, Flathead Lake supports the second highest fishing pressure of any lake or reservoir in Montana (Montana Department of Fish and Game 1976). During 1981-82, the lake provided 168,792 man-days of fishing pressure. Ninety-two percent of the estimated 536,870 fish caught in Flathead Lake in 1981-82 were kokanee salmon. Kokanee also provided forage for bull trout seasonally and year round for lake trout. Kokanee rear to maturity in Flathead Lake, then return to various total grounds to spawn. Spawning occurred in lake outlet streams, springs, larger rivers and lake shoreline areas in suitable but often limited habitat. Shoreline spawning in Flathead Lake was first documented in the mid-1930's. Spawning kokanee were seized from shoreline areas in 1933 and 21,000 cans were processed and packed for distribution to the needy. Stefanich (1953 and 1954) later documented extensive but an unquantified amount of spawning along the shoreline as well as runs in Whitefish River and McDonald Creek in the 1950's. A creel census conducted in 1962-63 determined 11 to 13 percent of the kokanee caught annually were taken during the spawning period (Robbins 1966). During a 1981-82 creel census, less than one percent of the fishermen on Flathead Lake were snagging kokanee (Graham and Fredenberg 1982). The operation of Kerr Dam, located below Flathead Lake on the Flathead River, has altered seasonal fluctuations of Flathead Lake. Lake levels presently remain high during kokanee spawning in November and decline during the incubation and emergence periods. Groundwater plays an important role in embryo and fry survival in redds of shoreline areas exposed by lake drawdown. Stefanich (1954) and Domrose (1968) found live eggs and fry only in shoreline spawning areas wetted by groundwater seeps. Impacts of the operation of Kerr Dam on lakeshore spawning have not been quantified. Recent studies have revealed that operation of Hungry Horse Dam severely impacted successful kokanee spawning and incubation in the Flathead River above Flathead Lake (Graham et al. 1980, McMullin and Graham 1981, Fraley and Graham 1982 and Fraley and McMullin 1983). Flows from Hungry Horse Dam to enhance kokanee reproduction in the river system have been voluntarily met by the Bureau of Reclamation since 1981. In lakeshore spawning areas in other Pacific Northwest systems, spawning habitat for kokanee and sockeye salmon was characterized by seepage or groundwater flow where suitable substrate composition existed (Foerster 1968). Spawning primarily occurred in shallower depths (<6 m) where gravels were cleaned by wave action (Hassemer and Rieman 1979 and 1980, Stober et al. 1979a). Seasonal drawdown of reservoirs can adversely affect survival of incubating kokanee eggs and fry spawned in shallow shoreline areas. Jeppon (1955 and 1960) and Whitt (1957) estimated 10-75 percent kokanee egg loss in shoreline areas of Pend Oreille Lake, Idaho after regulation of the upper three meters occurred in 1952. After 20 years of operation, Bowler (1979) found Pend Oreille shoreline spawning to occur in fewer areas with generally lower numbers of adults. In studies on Priest Lake, Idaho, Bjornn (1957) attributed frozen eggs and stranded fry to winter fluctuations of the upper three meters of the lake. Eggs and fry frozen during winter drawdown accounted for a 90 percent loss to shoreline spawning kokanee in Donner Lake, California (Kimsey 1951). Stober et al. (1979a) determined irrigation drawdown of Banks Lake, Washington reduced shoreline survival during five of the seven years the system was studied. The goal of this phase of the study was to evaluate and document effects of the operation of Kerr Dam on kokanee shoreline reproduction in Flathead Lake. Specific objectives to meet this goal are: (1) Delineate the extent of successful shoreline spawning in Flathead Lake both on-shore (to an approximate depth of 6.1 m below full pool elevation) and off-shore (approximately 6.1-21.3 m below full pool elevation). (2) Quantify and qualify influence of groundwater on reproductive success of on-shore spawners. The effects of groundwater on spawning and incubation on off-shore spawners will also be studied. Rates of groundwater discharge and groundwater chemistry will be established in spawning and non-spawning areas. Those data will be compared and contrasted in an attempt to delineate parameters affecting spawning site selection and embryo success. (3) Determine the relative contributions of major spawning areas to the total kokanee population

The Montana Rivers Study: Past, Present and Future

The Pacific Northwest Rivers Study was initiated in 1984 by a measure in the Northwest Power Planning Council\u27s Fish and Wildlife Program. Funded by the Bonneville Power Administration, the study was designed to identify, assess, and rate the significance of river-related natural resources values in Montana, Idaho, Washington, and Oregon and to produce a consistent and verifiable database. The Montana Rivers Information System (MRIS), the Montana portion of the Pacific Northwest Rivers Study, included the assessment of resident fisheries, wildlife, recreational, natural, and cultural features along 4,000 reaches of Montana\u27s rivers and streams. In addition to detailed descriptive and location information, each data base contains quantitative data on key features of each resource area such as species abundance, fishing press life, presence of species of special concern (fish and wildlife), boating suitability, scenic quality (recreation), scarcity, and scientific or educational use (natural/geologic features). The databases are managed in dBase III+ software; however, the programming can be compiled to run on any computer with MS/Dos operating system. Reports are available in hard copy, floppy disks, or through modems. The Natural Resources Information System (NRIS) in the Montana State library is the data manager for the MRIS. Direct all requests to NRIS: (406) 445-5356 (address listed above). In addition to data reports, NRIS can also provide criteria and other documents produced for MRIS. The MRIS is an ongoing federal and state interagency project. During the next phase (1990-1991) portions of the rivers system will be converted from tile state\u27s water code system to the Environmental Protection Agency (EPA) River Reach Number System. The EPA reach system, a geographically continuous system with reaches linked to one another, will be available in a Geographic Information System by 1991 with coverages compiled at the 1:100,000 map scale. Other planned updates will include connecting the system to other agency bases such as those of the Heritage Program, Montana Riparian Association, federal land management agencies, and for adding new data for land ownership, special management areas, consumptive and non-consumptive wildlife recreation, and river recreation

Pacific Northwest Rivers Study : final report, Montana /

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Impacts of water level fluctuations on kokanee reproduction in Flathead Lake.

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