Biology professor and students work on oyster restoration project

In Features
MARIAH CARRILLO / DAILY TITAN
MARIAH CARRILLO / DAILY TITAN

On an early morning in June of last year, the tide was low, giving a professor and students access to oyster beds they created a year ago. It would otherwise be buried under six feet of water.

Danielle Zacherl, Ph.D., a Cal State Fullerton biology professor, and her team of students stood in the sand at the Alamitos Bay. They had their headlamps strapped to their heads, shining beams of light in the dark morning and pulled on their rubber boots to begin their trek in the mud.

It was time to collect their one-year samples for the Olympia oysters restoration project.

The Olympia oysters are the only native oyster species to the West Coast. After the 1930s, the number of Olympia oysters plummeted due to overharvesting and changes in the wetlands, wiping out an entire habitat.

Since then, a larger species of oysters, known as Japanese oysters, which are commonly eaten on the West Coast, were brought in to be cultured and farmed and the Olympia oysters were forgotten.

“For the most part, interest in the oysters is driven by the commercial operation and because when that species declined so radically, they brought in the Japanese oyster, I think people kind of lost interest in (the Olympia oyster) for a while,” Zacherl said.

The oyster restoration project began in 2010 in Newport Bay. It started as a study to find the best environmentfor oyster restoration. Zacherl and a team of students created 20 miniature oyster beds with different bed designs to study the effect the bed designs had on oyster recovery.

The oyster beds were made by laying down a layer of dead Japanese oyster shells in a mud flat, which is literally a flat area with mud, Zacherl said.

All the oyster larvae requires is a hard surface to settle on, preferably an oyster shell, but it could be any hard surface including walls and pier pilings.

“Unlike other locations where they are restoring the oysters, here the oysters are regularly reproducing on their own,” Zacherl said. “They’re not forming beds anymore, but there’s enough of them living on pier pilings and sea walls that they were naturally reproducing on their own.”

Once the larvae finds a hard surface to settle on, it does not move.

“They actually glue one of their shells down to a hard substrate,” said Sara Briley, a biology grad student who has been working on her own thesis on the relationship between eelgrass and the Olympia oyster. “Once they settle, they just keep getting bigger and bigger and that’s where they are forever.”

In 2012, the actual restoration project began in Alamitos Bay. It was the first oyster restoration project in Southern California.

“The Alamitos Bay project was kind of different, it’s not replicated. It’s not an experiment,” Zacherl said. “This project was more about educating the public about oyster beds and the fact that they were once in Southern California and we’re trying to restore them now.”

The oyster beds play an important role because of its contribution to the marine ecology.

“Oysters, no matter the species, are bed-forming, or reef forming species. They cement against one another and when they do that they create a habitat,” Zacherl said.

The oyster beds, with its nooks and crannies, provide a structured habitat for other organisms in the sea. Before the restoration project, the oysters were living and reproducing in the bay, but they were not forming a habitat.

Since the beds’ introduction to the Alamitos Bay, the creatures such as limpets, crabs, barnacle and snails have begun living in the crevices in the oyster beds. Creatures that were not originally there, said Cristina Fuentes, a marine biology student who monitors the shell.

The oysters also act as water filters as they are filter feeders. When they eat, they filter their food out and together with their food they filter bacteria and sediment, thus improving water clarity.

After a setback in 2013, because the oyster beds were being covered with sand and mud washing onto the beds, and a few changes to the bed design, the oyster restoration project is producing great results.

Fuentes, who drives out at least once every month to monitor the effects the restored oyster beds, said the number of Olympia oysters has increased to 65 times more than the average population between June 2013 and January 2014.

Come June this year, Zacherl will lead a team of students out onto the Alamitos Bay again during the low tide, including Briley and Fuentes, to collect samples marking the second year of the project.

“It’s a great feeling knowing that I’m part of the first restoration efforts of the Olympia oyster in Southern California and the data that I have collected will provide information for future restoration projects,” Fuentes said.

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