Diamond Lake Warmwater Fishery Assessment Fall 1999

In an attempt to accurately assess the fish community in Diamond Lake, and to determine how to best manage the lake in the future, personnel from Washington Department of Fish and Wildlife Warmwater Enhancement Program conducted a detailed fisheries stock assessment in fall 1999. Fish were captured using boat electrofishing, gill netting, and fyke netting. Yellow perch (Perca flavescens) were the most abundant species collected by number and by total weight (kg). Largemouth bass and yellow perch proportional stock density values (PSD) are similar to those typically recommended for populations managed for panfish. The fish community of Diamond Lake appeared to be dominated by small predator and prey fish species that offer very limited opportunity for both catch and harvest. Age and growth data suggests that Diamond Lake would be a good candidate for inclusion under the current recommended WDFW slot-limit regulation for largemouth bass, if the management objective is to promote warmwater angling opportunities. This regulation consists of a five fish limit, fish 12"-17" are to be released, and only one fish over 17" may be retained. The intent of this regulation is to increase the number of quality length (> 300 mm; 12") largemouth bass available for catch and release in the lake. Additionally, under this regulation, the number of largemouth bass predators in the lake should increase and prey upon the now stunted panfish populations.