STRUCTURE AND CHARACTERIZATIONS FOR ROBUST POPULATIONS OF Ostrea lurida ON VANCOUVER ISLAND, B.C.S WEST COAST.

Jonathan P. Davis*, Brian L. Allen

Puget Sound Restoration Fund
590 Madison Ave North
Bainbridge Island, WA 98110
jdavis@bainbridge.net
A sizeable portion of our work in the Puget Sound is directed at stock recovery for the native Olympia oyster, Ostrea lurida. Our current practices include a focus on community ecology and efforts to understand the function of complex intertidal habitat like that found in a native oyster bed. As we learn more about the contemporary habitat requirements for these oysters, we have adapted our restoration practices. Our efforts include observing natural beds of native oysters whenever possible. By making assessments of these natural aggregations using the same measures we apply to our enhancement projects, we are able to compare our enhancements to the empirical microhabitat, community and population structure we find in a natural bed. One problem we face in Washington State, where the historic stocks of oysters were harvested in the early 20th century, is that we lack any sizeable examples in nature of an undisturbed and sustained beds of native oysters.

Upon learning of robust O. lurida beds near Espiranza Inlet, on Vancouver Island, B.C.s west coast, the Puget Sound Restoration Fund organized expeditions in 2008 and 2009 to find what we could learn from such populations. Our 2008 visit found beds of millions of oysters, where we characterized habitat and community fauna, and collected descriptive population statistics to represent relatively undisturbed and stable oyster beds. Tagged oysters were also deployed for growth trials.

In 2009 we returned to collect a suite of community and population data, employing GIS survey technology to incorporate microhabitat in a spacial analysis. Tissue samples from separate year-class cohorts were collected to examine the stock structure within the water body. We will present the results and analysis of these collaborative efforts to describe these populations.