Meeting Abstract
Shellfish utilize estuarine habitats, which are heterogeneous and can differ greatly from bay to bay, during many stages of their life history. These habitats are becoming increasingly more important for the management of shellfisheries, especially in the face of climate change, ocean acidification, and development. The Shellfish and Estuarine Assessment of Coastal Oregon project of the Oregon Department of Fish and Wildlife conducted extensive surveys of bay clam populations and estuarine habitats in three Oregon estuaries: Netarts Bay, Tillamook Bay, and Yaquina Bay. These estuaries have active bay clam fisheries, but differ in size, geomorphology, and distribution of abiotic and biotic features. This analysis evaluates clam-habitat associations and generates quantitative models of clam distribution for four recreationally and commercially targeted bay clams: butter clams (Saxidomus gigantean); cockles (Clinocardium nuttallii); gaper clams (Tresus capax/nuttallii); and littleneck clams (Leukoma staminea and Venerupis philippinarum). We used nonparametric multiplicative regression (NPMR) to predict the distribution of bay clams. The best fitting models identified specific variables that predicted clam density and biomass within and among estuaries. Results indicate that assessment efforts and management decisions may need to be estuary-specific rather than coast-wide for some clam species. Bay clams are managed as a unit in Oregon and these results will inform decisions pertaining to harvest, critical habitats, aquaculture, land development, and resilience to climate change and ocean acidification.
