Olympia Oyster Restoration
The Olympia oyster (Ostrea lurida) is the only native oyster species on the west coast of the U.S. and Canada. It was once widely distributed from Alaska to Baja California, covering large expanses of intertidal areas as oyster “beds.”
How Oysters Benefit Nature and People
Olympia oysters were once an important food source for native Californians and an ecologically-important habitat for numerous other aquatic organisms. Oysters provide habitat and refuge for other organisms, such as octopus, crabs and juveniles fishes, who shelter on the reefs/beds. Thus, they not only increase habitat complexity, but also increase biodiversity. Here in California, you might notice that the endangered California least tern uses oyster shell to line its nest! Oysters are filter feeders, improving water clarity, and helping to stabilize mudflats
Threats to the Species
Beginning in the 1900s, overharvest of this species, increased coastal development, destruction of wetlands, and increased water pollution led to significant declines of the Olympia oyster. Today, native oysters exist primarily as small remnant populations in bays and estuaries. However, we have lost an entire native habitat as well as the critical ecological and economic benefits provided by once healthy, fully-functioning components of our estuarine ecosystems. Today, over 85% of the world’s oyster reefs have been lost since the 1900′s and are one of the most severely impacted marine habitats on the planet.
At a local level, field surveys of Alamitos Bay in 2010 revealed that native oysters are present, however, there were no natural intertidal “beds” of oysters anywhere in Alamitos Bay for oyster larvae to settle and grow in large communities. Oysters are gregarious settlers and while they will settle on many hard substrates, they prefer oyster shell. This is how oyster reefs/beds are created.
Coastkeeper's Restoration Efforts
In June 2012, Coastkeeper, in partnership with California State University Fullerton, CSU Long Beach, and KZO Education, restored oyster habitat at the Jack Dunster Marine Reserve in Alamitos Bay, CA. Teams of scientists, students, and community volunteers, laid a new oyster bed using “dead” oyster shell to provide the impetus for future settlement of baby oysters, or oyster spat. Since then, we have seen the bed grow in size and in the summer of 2013 began to see significant increases in oyster settlement, survival, and growth!
We will continue to monitor this habitat and have plans to continue these efforts not only in Alamitos Bay but also throughout other bays and estuaries in southern California in an attempt to restore oyster beds to fully-functioning habitats. These beds will provide habitat for other fish and invertebrate species, may help improve water clarity, particularly for sunlight-loving eelgrass beds that often occur adjacent to or in and around oyster beds, and will help inform other shellfish and habitat restoration projects in southern California.
Funding: NOAA Restoration Center, State Coastal Conservancy.