Daniel Zacherl, a professor at Cal State Fullerton, leads restoration projects along the Southern California coast that use oysters and complementary species like eelgrass to slow down coastal erosion.
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Jill Replogle
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LAist
)
Topline:
Cal State biologists and the group Orange County Coastkeeper are working together to use oyster shells from local restaurants to restore the once-abundant oyster beds along the coast and, by doing that, protect the shoreline from erosion and rising seas.
How does that work? Local restaurants donate discarded oyster shells. Those shells cure in the sun to remove pathogens, then hang off of docks in Huntington Harbour and elsewhere to provide a landing pad for oyster larvae floating through the water.
Once seeded with baby oysters, those shells are used in living shoreline projects designed to buffer the coastline.
Why oysters? When oyster larvae settle on shells, they start to secrete their own shell, effectively gluing the shells together to form oyster beds that encourage sedimentation and dampen the eroding force of waves. Oysters also filter the water, removing excess nutrients that cause harmful algal blooms.
It’s well before the lunch hour when a worker lugs a large plastic storage bin out of the kitchen at the Bluewater Grill in Newport Beach and into the back of Kaysha Kenney’s minivan.
The bin is full of discarded oyster shells from the previous night’s dinner service, plus some lemons and half-eaten bread. Kenney wants the shells, but the extra food bits are OK, she said, “because they sit out in a field and they have little animals that will come and kind of pick off the food scraps.”
This pickup is the first phase of a project led by Kenney’s group Orange County Coastkeeper. The goal is to use oyster shells from local restaurants to restore the once-abundant oyster beds along the coast and buffer the shoreline from erosion and rising seas.
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Listen: How OC is using oysters to help stabilize shorelines
Though the shells Kenney collects are non-native oysters, Coastkeeper’s project is focused on restoring Olympia oysters — the only native species along the West Coast. The species has been decimated by coastal development and overharvesting, starting in the Gold Rush days when they fed tens of thousands of hungry fortune-seekers.
In early fall, Orange County Coastkeeper collected dozens of oyster shell strings hanging off docks in Huntington Harbour. This year, they recruited more than 700 baby oysters or "spat" that will be transplanted to coastal restoration projects.
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Courtesy Coastkeeper
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Stop 2: San Joaquin Marsh
With the blue Coastkeeper minivan full of stinky shells, Kenney heads inland to a hot, sunny patch of land next to the San Joaquin Marsh in Irvine. Here, she weighs each restaurant’s contribution, and spreads the shells out to cure in the sun to rid them of pathogens — and any leftover horseradish and tabasco sauce.
California regulations require the shells to cure for at least six months before they can be put back into the water. These particular shells are destined for the Seal Beach National Wildlife Refuge. Coastkeeper is working with California State University, Fullerton, and the U.S. Navy to build what’s called a living shoreline to help protect Navy buildings in the refuge that are threatened by erosion.
”A living shoreline is where we take an eroding shoreline and we effectively replant it with living plants and animals that can stabilize that shoreline,” explained Danielle Zacherl, a biology professor at Cal State Fullerton who’s leading the project.
And using discarded shells helps reduce restaurant waste.
“Think about this natural product that's getting sent to landfills that really could be doing so much more good,” Zacherl said.
Kenney spreads out the morning's collection from restaurants onto a patch of land near the San Joaquin Marsh in Irvine. The shells will cure in the sun for at least six months to rid them of pathogens.
(
Jill Replogle
/
LAist
)
Living shorelines are becoming popular across the country. They’re seen as more cost-efficient and ecologically friendly compared to what’s known as hard armoring, like seawalls and riprap. Zacherl and Coastkeeper have teamed up on several living shoreline projects along the Southern California coast, including in Newport Bay and Long Beach’s Alamitos Bay.
Oyster beds anchor the shoreline, keeping it from washing away, Zacherl explained.
“They also encourage sedimentation by generating eddies. The shells popping up into the water column slow the water velocity and allow sediment to filter down,” she said. “That's really important for coastal habitats right now, especially in the face of climate change.”
Daniel Zacherl, a professor at Cal State Fullerton, leads restoration projects along the Southern California coast that use oysters and complementary species like eelgrass to slow down coastal erosion.
(
Jill Replogle
/
LAist
)
Oysters also filter the water, removing excess nutrients that cause harmful algal blooms. In fact, a single adult oyster can filter up to 50 gallons a day. They also improve water quality for eelgrass — which sequesters carbon, provides habitat for ocean critters and also helps prevent erosion.
The living shoreline planned for the Seal Beach refuge will be made up of a combination of oyster beds, eelgrass and another coastal plant, cordgrass. But first, Zacherl needs live oysters.
That’s where folks like Craig Schauppner come in.
Craig Schauppner
(
Jill Replogle
/
LAist
)
Stop 3: Huntington Harbour
Schauppner is one of close to 90 residents in Huntington Harbour, at the northwestern end of Huntington Beach, who has become a kind of oyster nanny. Last spring, Coastkeeper gave him and the other volunteers strings of discarded and cured oyster shells to hang off their docks.
Oyster larvae floating through the water settle on those shells and start to secrete their own shell. Combined with other oysters, they effectively glue themselves together to form oyster beds.
During a visit last month, Schauppner pulled up a wire strung with more than a dozen oyster shells and pointed out a small dark circle on the inside of one of them.
“ So you could see, like right there, there's a spot. There might've been an oyster there at one time, but maybe a predator came and ate it or something like that,” he said.
His shell strings weren’t particularly attractive to baby oysters this year. But that’s OK, he said.
An oyster bed restoration project in Jack Dunster Marine Biological Reserve in Long Beach.
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Courtesy of Danielle Zacherl
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“Part of the project is to figure out where we can harvest oysters, where they can grow and, you know, where to avoid,” he said. “So I’m contributing to the data, right?”
At the end of September, Coastkeeper retrieved the shell strings from Schauppner and other volunteers in Huntington Harbour. They harvested more than 700 baby oysters, called “spat,” which were then transplanted to Seal Beach National Wildlife Refuge for the living shoreline project.
Kenney from Coastkeeper said it’s sometimes hard for the oyster nannies to let go but hopefully a little easier knowing their slimy charges will be helping clean the water and reestablish a resilient California coast.
Wanna help restore the coast?
Orange County Coastkeeper has multiple volunteer opportunities, including caring for shell strings and transporting oyster shells from restaurants to be used in living shoreline projects.
