Freshwater Mussels: Lake Crescent Assessment and Monitoring

Lake Crescent is a pristine lake in Olympic National Park enjoyed by thousands of visitors each year. Through a Washington's National Park Fund grant, the lake's native mussel population will be surveyed not only to protect the current mussels, but also to prevent invasion by non-native species. The lake’s population of filter-feeding freshwater mussels live as deep as 270 feet and are a major factor in maintaining the lake’s near-pristine water quality. The freshwater mussels, and the lake itself, are vulnerable to the introduction of invasive zebra and quagga mussels.

Using a miniature remote operating vehicle (ROV) deployed from an NPS boat, biologists will assess the current status of the native mussel population and establish a routine for monitoring lake activity. The arm on the ROV will allow biologists to pick up and move mussels at depth.

Pictures have been provided by park biologists.