DETERMINING DISTRIBUTION AND SIZE OF LARVAL PACIFIC GEODUCK CLAMS (PANOPEA GENEROSA GOULD 1850) IN QUARTERMASTER HARBOR (WASHINGTON, USA) USING A NOVEL SAMPLING APPROACH

ABSTRACT Realistic species-specific information about larval life history is necessary for effective management of shellfish and parameterization of larval connectivity models. The patchiness of dispersing larvae, and the resources needed for sorting and identifying them, has limited many studies of larval distribution in the field, especially for species that are less common. In particular, little is known about in situ larval distribution of Pacific geoduck clams (Panopea generosa Gould 1850), a commercially important species found in Puget Sound, WA. A novel approach—time-integrating larval tube traps paired with molecular identification and sorting (FISH-CS)—was used to determine the distribution of geoduck larvae over 4 mo at 3 stations in Quartermaster Harbor. Larvae were found consistently at the surface and thermocline rather than at the bottom. More and larger larvae were captured in the inside and middle of the harbor than the outer harbor, indicating at least some larval retention. Two pulses o...