2013 Warmwater Fisheries Survey of Lake Tapps, Pierce County, Washington

Lake Tapps, Pierce County, Washington was surveyed by the Washington Department of Fish and Wildlife’s Warmwater Enhancement Program from October 21 â€" 23, 2013 to assess the warmwater fish community (e.g. growth rates, condition, age, size structure) and the zooplankton populations (e.g. density, size structure) to evaluate the current fishery and its zooplankton forage base in order to develop management considerations. Two three-person crews utilized boat electrofishers, gill nets, fyke nets and zooplankton nets to accomplish study objectives. The Lake Tapps fish assemblage was primarily composed of small forage species, with Largescale Suckers Catostomus macrocheilus, representing the majority (57%) of the biomass. Proportional stock densities and relative stock densities of Smallmouth Bass Micropterus dolomieu, Largemouth Bass M. salmoides, Brown Bullhead Ameiurus nebulosus and Tiger Muskie Esox masquinongy x E. lucius suggest opportunities exist in Lake Tapps for anglers to catch large fish. Overall, growth rates, condition factors and age classes were below national and state averages. Lake Tapps zooplankton total lengths and densities were on average smaller and less densely distributed than zooplankton populations from American Lake, Banks Lake and Lake Roosevelt. Patterns of Lake Tapps zooplankton total lengths and densities, in conjunction with the fish assemblage structure, are indicative of an overgrazed zooplankton population. We postulate that additional competition for preferred prey (e.g. Daphnia spp.) by stocked planktivores i.e., (salmonids) may result in cascading detriments on the warmwater fish assemblage.

We identified four management options to maintain a healthy fish community and provide successful angling opportunities for Lake Tapps:

1. Explore options to improve primary productivity by decreasing the frequency of drawdowns and depth reductions, decrease removal of aquatic macrophyte habitat, decrease input of cold, nutrient poor glacial runoff, and increase residency time of Lake Tapps waters.
2. Continue to stock Tiger Muskie at the current rate to continue the reduction of overcrowding by Largescale Sucker, continue beneficial predatory trophic effects, and provided increased opportunity for anglers.
3. Expand promotion of the Smallmouth Bass and Tiger Muskie fisheries, as they represent unique angling opportunities within the region, in addition to increased promotion of underexploited populations such as Brown Bullhead and Rock Bass.
4. Identify funding to stock Tapps Lake with 20-30 catchable (2.5 fish per pound) size rainbow trout per surface acre (50,000 â€" 80,000 fish) annually for three years and evaluate angler participation (anglers days directed at rainbow trout), success (catch/harvest per hour), and fish growth and condition. Based on the cost of $2.32 per pound of fish as currently charged by Trout Lodge, total approximate costs will range from $46,000 to $74,000 for 50,00 to 80,000 fish respectively.