Larval Exchange in Olympia Oyster Recovery
Researchers use seawater chemistry to trace larval exchanges between Olympia oyster populations.
Bonnie Becker, University of Washington, Tacoma, School of Interdisciplinary Arts and Sciences
Brian Allen, Puget Sound Restoration Fund
Henry Carson, Washington Department of Fish and Wildlife
Betsy Peabody, Puget Sound Restoration Fund
Andrés J. Quesada, Northwest Indian College, Salish Sea Research Center
Brent Vadopalas, University of Washington, School of Aquatic and Fishery Sciences
Washington Sea Grant-funded researchers partnered with tribes, shellfish managers and a local restoration group to determine how far Olympia oyster larvae disperse. From 2015 to 2016, the researchers collected planktonic larvae and recent settlers, and sampled over 14,000 adults throughout Puget Sound to collect brooded larvae from more than 100 oysters using a novel sampling method that is non-lethal to the parent animal. The researchers then examined the larvae using elemental fingerprinting, a technique that measures the elemental makeup of the animal’s shell, which reflects the environment in which that shell was formed, which was used to map settlers back to the brooding region.
Washington’s only native oyster, the Olympia, was overharvested starting in the 1850s, resulting in its depletion. Despite protections instituted by state agencies, the species has yet to recover. Olympia restoration is now a regional priority whose success relies on reestablishing self-sustaining populations that can replenish surrounding beds. Information about how far Olympia larvae disperse in Puget Sound could aid these restoration efforts.
This study was the first use of elemental fingerprinting of an invertebrate in Puget Sound. Three regions in Puget Sound were found to have unique elemental fingerprints for brooded larvae. However, researchers were largely unable to map settlers back to brooding region based on data collected in this study. Despite that challenge, the ecological data gathered supports the conclusion that Olympias don’t travel far from their source, which is consistent with other findings and suggests that seeding Olympias near site of origin would provide greater restoration success. In addition, the study was successful in developing a non-lethal sampling technique which has been used in other studies. The project also provided workforce development opportunities for nine students.