Carlsbad Beach is a great walk directly opposite Agua Hedionda Lagoon.

As we rush by on I-5, Carlsbad Boulevard, or the train tracks, some of us may wonder what all those white buoys in Agua Hedionda Lagoon are about.

Now, we can see for ourselves what lives beneath them and why scores of pelicans snooze there. After 70 years of private seafood farming research and experiments in the outer pool of the lagoon, the public is now welcome to take tours at Carlsbad Aquafarm. The visit is perfect for all ages and offers fascinating science about the aquafarm’s coexistence with the neighboring desalination plant. Plus, you’ll discover a lot about the sex life of oysters, not to mention how to impress your date with new shucking skills. Recently, visitors from Sweden, Los Angeles, Redding, and Escondido exhaled satisfied oohs and aahs while downing plump, juicy shellfish straight out of the shells. “Has anyone ever found a pearl?” one man asked. “No,” says our guide, Rachel Taylor. “Edible oysters don’t grow pearls. Ours are very good spitters; they spit out the sand.” She says oysters also grow more quickly in Carlsbad than in Washington State due to warmer weather.

Carlsbad’s warm waters help oysters grow quicker than in Washington State.

The aquafarm produces Pinnacle Point oysters and Carlsbad mussels. Don’t expect to find them on restaurant menus as the farm only sells directly to customers via online orders. Oysters are $20 a dozen; mussels $8 a pound. Whole Foods buys mussels each day.

Mussels clump together for safety as they grow on ropes in Agua Hedionda Lagoon.

A total of 2 million pounds of shellfish grows here at a time. Oysters grow in floating trays, while mussels cling together on ropes, all under floats. Seafood farming began privately in this “third pool“ of the lagoon in 1952 as a research project with UCSD, with lobsters as the first experiment. Carlsbad Aquafarm has operated here for 30 years and still partners with research institutions as well as the City of Carlsbad to keep a working waterfront going. It has been open to the public now for six months. An oyster’s journey to consumption is explained during the one-hour tour. Each female spawns 200 million eggs every spring. The farm takes some of the eggs via syringe through the shells and also buys some from other operations, says Taylor. “It’s basically an IVB [in vitro breeding] process.”

“Why do the oysters taste so creamy?” one woman asks.

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Infant oysters have no shells but start developing them at 2 weeks old.

“It’s the caviar—the eggs. It’s spring,” Taylor explains. “When the water warms up, they make babies.” Infant oysters have no shells but start growing them within two weeks.

A breeder oyster can become a “whopper” by age 5 years.

One oyster on display in a shallow trough made us all gasp. It was about 10 inches long. “That’s a breeder,” says Taylor. “It’s about 5 years old. You wouldn’t want to eat it. It would be tough.” The farm keeps breeders until age 5 but sells others at 11 months. The young ones go through a tumbling machine each month for 60 seconds to shape their shells. “Normally,” says Taylor, “waves rub off rough edges and polish a shell into a crescent shape—but we don’t have waves here, so we do this. The shape gives an oyster more room to grow.” Oysters are intertidal, so they can be out of the water for a while. She says pelican poop also helps their development because it fertilizes the algae. Before the shellfish are sold, they go through tanks of flowing seawater to be flushed and purged.

Young oysters go through a tumbler each month to help shape their shells.

The farm is in a symbiotic relationship with the adjacent Carlsbad Desalination Plant. Both operations are on land owned by NRG Energy. “The oysters pre-clean the ocean water before it goes into the plant,” says Taylor. “The plant sucks in so much water that it helps keep a strong artificial current to pull water into the lagoon. After the purification process, the briny water is released back into the lagoon near Carlsbad Boulevard, where sometimes seals and sea turtles are seen.”

Filtration by the shellfish also encourages eelgrass growth, which provides a safe habitat for a variety of marine life. Visiting fish keep the pelicans well fed; they devour up to four pounds a day. Other lagoon visitors have included octopi, starfish, seahorses, and even a humpback whale.

The entrance to the aquafarm is tricky to spot because no signage is allowed on the NRG frontage. It’s best to map the address—4600 Carlsbad Boulevard—and look for the driveway opposite Lifeguard Tower 30. The tall Encina Power Plant under deconstruction on the land is the biggest landmark.

Tasha Tuong and Minh Vuong-Dac came from Los Angeles to try their hands at shucking oysters at Carlsbad Aquafarm.

The tour cost is $40 per person (ages 13+). Weekend tours are expected to be booked solidly through summer. Weekdays still have open spots, which can be booked online. In October, the parking area will move to the north end of the lagoon, where a big OYSTER FARM sign is displayed. For more information, check out carlsbadaquafarm.com or call 760-908-2744.

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Edible San Diego Issue 66 Summer 2022
Cover Image by Dave Rudie.

Published in the print edition of Edible San Diego's summer 2022 issue.

Read issue 66 online now.

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About the Contributor
Julie Pendray
Julie Pendray has experience working in the natural resources and environmental field, and also moonlighting in the food industry and traveling for stories. She is a certified master composter, an avid gardener, and loves to learn about nutrition. She has covered California as a journalist for over four decades.
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