2000 Warmwater Fisheries Survey of Eloika Lake (Spokane County)

Eloika Lake was surveyed by a three person investigation team May 15 - 18, 2000. Fish were captured by boat electrofishing, gill netting, and fyke netting. Twelve fish species were collected. Largemouth bass (Micropterus salmoides), pumpkinseed sunfish (Lepomis gibbosus), and black crappie (Pomoxis nigromaculatus) were the most abundant game fish species. Tench (Tinca tinca) were the most abundant species by weight and number. Yellow perch (Perca flavescens), brown bullhead (Ameiurus nebulosus), yellow bullhead (Ameiurus natalis), black bullhead (Ameiurus melas), green sunfish (Lepomis cyanellus), rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), and grass pickerel (Esox americanus) were also collected. The Eloika Lake largemouth bass population is robust as evidenced by high growth rates and high stock density index values compared to other Washington lakes. Panfish populations including yellow perch, black crappie, and pumpkinseed sunfish are quality as evidenced by high growth rates and high PSD values. The yellow bullhead population is also of a high quality and offers additional angling opportunity. Considering the high density of aquatic vegetation occurring in Eloika Lake at times, it is curious that panfish species are not stunted as is often observed in densely vegetated lakes. One explanation may be the presence of grass pickerel, a small member of the pike family, in the community. The addition of this predator may add to the overall predation on abundant panfish in the lake, thereby keeping those populations from stunting. Stocked brown trout appear to offer a unique opportunity for fish of quality size, whereas rainbow trout offer little. Although largely undesirable to anglers, tench will likely continue as part of the Eloika Lake fish community due to the limited feasibility of applying typical fisheries management control techniques, such as biological controls or rotenone rehabilitation, due to the lakes connectivity to the Little Spokane River. Future management considerations include monitoring the response of populations to the recently imposed slot-limit on largemouth bass and conducting a creel survey to determine angler harvest. Additionally, careful consideration of any plan to modify current levels of aquatic vegetation to improve boater access is advised. Currently and historically, the effect of aquatic plant abundance on the quality of the fish community is unclear and literature suggests that the response of fish populations to vegetation removal is difficult to predict.