West Coast
These reef balls may seem dry and brittle, but to environmentalists, the pacific oyster shells are a source of life that they hope will bring many benefits to the bay. Port of San Diego image.

CA - How Pacific Oysters are Saving the San Diego Bay

To clean the water and preserve the wetlands, the San Diego Bay is part of a significant preservation effort years in the making. Pacific oyster shells from the Carlsbad Aquafarm will be crushed up and used as a life source to benefit the bay.

SAN DIEGO— On Dec. 9, the Port of San Diego sent out a press release announcing the release of more than 300 “reef balls’ into the San Diego Bay to help protect South Bay from rising sea levels.

The Port of San Diego, in partnership with the California State Coastal Conservancy and U.S. Fish & Wildlife Service, has begun the launch of the South Bay Native Oyster Living Shoreline Project adjacent to the Chula Vista Wildlife Refuge by installing “reef balls.” The project has been years in the making and is the latest of several Port projects to protect the shoreline from impacts related to rising sea levels and increase San Diego Bay’s biodiversity by creating new marine habitats.

The project costs approximately $960,000 and is fully funded via grants from the U.S. Fish and Wildlife Service and Builders Initiative. The cost covers the project’s fabrication, installation, and long-term monitoring.

The objective of the project is to demonstrate the ability to attract and establish native oyster populations that create structurally complex “reef” habitats for fish, birds, invertebrates, and aquatic plants. The project is also expected to improve local water quality via oyster water filtration and settling of sediments and increase wetland connectivity to intertidal and subtidal lands.

The project utilizes a compatible approach by which constructed reef ball elements are being placed in a series of six batches. Each reef array includes 15 reef groups composed of four reef ball elements made of baycrete, which is concrete mixed with local sand and oyster shell aggregate, placed in a square pattern for a total of 360 reef ball elements and 90 reef groups. The elements will be placed at specific elevations to enhance the recruitment of native oysters.

The oyster shells came from the Carlsbad Aquafarm, a market for sustainably farmed seafood, and now the oysters being brought to the San Diego Bay will serve a whole new purpose.

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