Rebuilding Olympia Oysters,Ostrea luridaCarpenter 1864, in Fidalgo Bay, Washington

Abstract

The Olympia oyster, Ostrea lurida,† is native to the Pacific Coast of North America and was common in Puget Sound prior to the arrival of European settlers. Over harvest in the late 1800s, combined with severe pollution in the first half of the 20th century from pulp mills, drove many Puget Sound beds to near extinction. Olympia oysters can still be found throughout most of their historic range, but current populations are mostly limited to remnant aggregations where habitat characteristics remain favorable. Whereas Olympia oysters are still present in Puget Sound, their numbers do not compare with the expanses of Olympia oysters that supported a thriving oyster industry in the mid-1800s. One reason for rebuilding Olympia oyester populations is to regain the ecosystem benefits associated with larger assemblages. Skagit County Marine Resources Committee, working in cooperation with shellfish industry, tribal, and community partners initiated a project to establish self-sustaining Olympia oyster beds in Fidalgo Bay near Anacortes, WA. Thus, oysters on these beds must survive, grow, spawn, and produce larvae that recruit to the new beds and surrounding areas. Olympia oyster seed on Pacific oyster cultch were planted in Fidalgo Bay during 2002, 2003, 2004, and 2006. Survival and growth of planted seed has been excellent at the first enhancement site. With the addition of seed on cultch during four years and augmentation of the enhancement site with five cubic yards of Pacific oyster shell in 2006, a structured oyster bed is gradually emerging. Deployment of temperature sensors in 2006 showed that water temperatures easily reached the minimum temperature for gameteogenesis and spawning. Examples of larval spawning (veligers in the mantle cavity) and natural postlarval recruitment to the enhancement site were documented in 2006. Several new sites within and around Fidalgo Bay are being evaluated for future rebuilding efforts.