In 2004, a pilot freshwater mussel survey was conducted to better understand the density, age and size distribution of the western pearlshell mussel, Margaritifera falcata, in three King County streams. One study site was located in Bear Creek, a stream in the Lake Washington Watershed known to support at least one large mussel bed thought to be in decline. The other two study sites were located in Covington Creek in the Green River Watershed and Stossel Creek in the Snoqualmie River Watershed. Concern regarding freshwater mussels in upper Bear Creek has increased over the past two decades with increasing reports of dead and dying mussels and a general overall decline in numbers observed by local residents and County staff. Evidence was observed of a similar decline at the Covington Creek site.