Nearly 200 tons of artificial oyster reef installed in the San Diego Bay is helping to revitalize the shoreline to promote biodiversity and protect against erosion.
The San Diego Bay is a sanctuary of marine and terrestrial biodiversity. Many species of wild flora and fauna depend on these types of wetlands. They are crucial habitats for migratory species such as birds and marine life, but over the years, these types of wetlands have been decreasing.
The Port of San Diego, in partnership with the California State Coastal Conservation and the U.S. Fish and Wildlife Service, installed 360 oyster reef balls as part of their South Bay Native Oyster Living Shoreline Project next to the Chula Vista Wildlife Refuge.
Historically in San Diego Bay, eelgrass coexisted with oyster reefs. Today, new artificial oyster reef balls replace the reefs destroyed by urban runoff, development, pollution and climate change.
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San Diego Bay represents approximately 50% of eelgrass in Southern California and 15% statewide, according to Timothy Barrett, Environmental Specialist for the Port of San Diego.
"What we as the Port are trying to do is not only protect, but enhance the opportunity for eelgrass to thrive in San Diego Bay," Barrett said.
In addition to absorbing carbon, eelgrass acts as a nursery for juvenile fish and as food for aquatic birds. The new oyster reefs will enhance this crucial vegetation.
Each reef ball weighs 1,000 pounds. They are composed of oysters and local sediment. The reef balls are positioned in groups at different elevations. There are 360 new reef balls that will help new oyster reefs thrive in this area. In addition to increasing biodiversity, these areas will also help prevent wave erosion.
"The structural component of it is strong enough to tackle any kind of wave energy that’s coming into the local location," Barrett said. They act as the bones for the new reef to form on top of them."
"Climate change is changing sea levels and causing erosion along the coast," said Rafael Castellanos, commissioner of the Port of San Diego. "This project is very important because it helps us prevent coastal erosion and sea-level impacts."
In addition to preventing erosion, the new reefs will help birds nest when the tide rises, something that is increasingly difficult with rising sea levels.
"We are incorporating bird monitoring, looking at species and abundance. As well as fish population studies, obviously oyster and shellfish studies and invertebrates, really any type of species that potentially use the reef and adjacent areas," Barrett said. We are interested to see how this project has improved performance for habitat for the area."
The project’s total cost is approximately $960,000 and is funded via grants from the U.S. Fish and Wildlife Service and Builders Initiative. The cost covers the fabrication, installation, and long-term monitoring of the project.
It is expected that during the Spring different types of microorganisms will grow on the artificial reef balls. Within a couple of years the artificial reefs will be covered with oysters. This means that in the future, San Diego Bay will have cleaner water as each oyster has the ability to filter up to 50 gallons of water per day.
Editor's note: This story has been updated to correct the spelling of Timothy Barrett's name.