Quantifying larvae to aid restoration efforts of the Olympia oyster (Ostrea lurida) in Fidalgo Bay, WA

Quantifying Larvae to Aid Restoration Efforts of the Olympia Oyster (Ostrea Lurida) in Fidalgo Bay White SW¹, Becker BJ¹, McCartha MM¹, Hintz MH1,², Behrens, MD3, Allen, B4, Kim SK¹, Mullins DM¹, Matheson-Margullis HR1, Centurion, R1 1- University of Washington Tacoma 2- University of Washington School of Aquatic Fisheries Sciences 3- Pacific Lutheran University 4- Puget Sound Restoration Fund Olympia oysters (Ostrea lurida), provide ecosystem benefits through formation of reefs, water filtration, and increased biodiversity. This native species was driven to near extinction due to a combination of pollution, overharvesting, and habitat alteration, and is now being actively restored to the Salish Sea. Successful restoration of natural populations is improved by understanding the early life history of target sessile marine invertebrates, including time of spawning, larval distribution and settlement. Like most marine invertebrates, O. lurida produce thousands of larvae to ensure survival for a small percentage of its offspring. This microscopic larval stage is the only mobile form of development for oysters. In this study, samples were collected during Summer 2013 from eight stations at an active restoration site in Fidalgo Bay, WA, five in the intertidal and three in the subtidal, to capture larval peaks and map distribution. Plankton samples were sorted using microscopy to investigate spatial and temporal distributions of O. lurida larvae. There were peaks in brooding adults, planktonic larvae and settlers that were close together in time, indicating that local larvae could be remaining in the bay or regional populations were synchronized. Results indicate that larvae and settlers were not evenly distributed and were concentrated near suitable habitat with adults present. Larvae tended to be found near the surface of the water in the subtidal stations. Understanding the changes in larval distribution can help inform restoration efforts. These restored populations of Ostrea lurida will attract fish, invertebrates and other marine organisms throughout Fidalgo Bay