1998 Warmwater Fisheries Survey of Liberty Lake

To evaluate the current conditions and to better understand how to best manage the Liberty Lake fishery, personnel from Washington Department of Fish and Wildlife's (WDFW) Warmwater Enhancement Program conducted a fish community survey of Liberty Lake during August and September 1998. Dissolved oxygen levels were within the desirable range for warmwater fish during the sampling period. The low number of stock length fish collected for most species resulted in broad confidence limits for PSDs making their interpretation difficult. Nine species of fish were collected. Bluegill sunfish (55.1%) and pumpkinseed sunfish (13.4%) were the most abundant species by number. Walleye (26.5%) and bluegill sunfish (19.7%) contributed the most to the biomass by weight. Results of this survey indicate that past walleye fry stocking has not contributed to the density of walleye in the lake. Survival of walleye stocked as large fingerlings (130-170mm TL) is higher in Liberty Lake. Therefore, walleye >5 inches (130mm TL) should be used in future stocking plans. In order to establish a walleye population in Liberty Lake, 127- 178mm TL (5-7") walleye should be stocked at the rate of 25-50 per surface acre. Liberty Lake data also suggests that it would be a good candidate for inclusion under the current recommended WDFW slot limit regulation for largemouth bass. This regulation consists of a five fish limit, fish 12-17 inches are to be released, and only one fish over 17 inches may be retained. Adopting this regulation for largemouth bass should complement efforts to establish a walleye population for controlling overabundant warmwater fish species in Liberty Lake.