Above Left:  Native oysters at Ladysmith harbor, Vancouver Island.  Above Right:  Native oysters at Yaquina Bay, OR.  Below Left: Native oysters at San Francisco Bay.  Below Right:  Maria measuring tidal height at San Francisco Bay.

The focus of my M.S. degree thesis is on the biogeography and phylogeography of the native west coast oyster, Ostrea conchaphila. Once abundant across its entire range, which extends from Sitka, AK to Cabo san Lucas, Baja California Sur, Mexico, natural populations of the native oyster were over-harvested and depleted by the early 1930s. Presently I am assessing the current status of intertidal populations at 25 historical sites across the entire range by establishing presence/absence and measuring maximum densities. At the same time, I have been collecting samples from sites as far north as Vancouver Island and as far south as Baja California in order to examine the phylogeographic structure of this species. This will be the first large-scale comprehensive biogeographic survey for O. conchaphila. Both the biogeographic survey and the population genetics study will provide baseline data for future projects in genetics and larval tracking that will examine population connectivity.

Maria near a bed of Japanese Oysters

Phylogeography and biogeography of the native oyster, Ostrea conchaphila