California Oil Platforms, the Unlikely Broodnest for Local Aquafarmers

The phrase California ranching brings to mind a classic Steinbeck inspired scene of cattle roaming a grassy expanse towards the open horizon. It’s a wonderful thought, but any modern Californian, or at least anyone who has driven the 5 freeway between LA and San Francisco, knows that the days of ranching on a wide open plain are over. In fact, the millennial California rancher may not be terrestrial at all. Aqua farmers at Catalina Sea Ranch are breaking the mold and taking ranching to a place Steinbeck never could have imagined, out to sea.

Currently, according to the National Oceanic and Atmospheric Administration, the United States has a $10.4 billion seafood trade deficit that continues to grow. However, Catalina Sea Ranch President and CEO, Phil Cruver, believes he has found a way to combat the seafood trade deficit using a method of shellfish farming that also addresses the environmental and sustainability challenges of traditional aquaculture.

Typically aquaculture takes place near shore, in bays and estuaries, and often displaces valuable natural wetlands. Further complications include invasive organisms, pollution from urban runoff, and predation. To preserve California’s valuable nearshore habitats and avoid these other complications, Catalina Sea Ranch takes its aqua farms miles offshore.  Their first site takes up 100 acres on the San Pedro Shelf—a large underwater plateau about 150 feet to 200 feet deep that quickly drops off to about 3,000 feet, creating natural upwelling that delivers an abundance of nutrient-rich phytoplankton from the deeper water.

The technology is ground breaking, using a series of anchor buoys and ropes to cultivate the shellfish. The anchor buoys are made of fiber-reinforced high-density polyethylene and are pressurized with air. Cruver said, “This is a new technology, and they’re guaranteed to last 20 years, so you won’t find them washing up on the beach like their cheap predecessors.” The estimated production of this 100 acre farm is 2.5 million pounds of mussels each year, putting a tiny dent in our nation’s whopping import of live mussels equaling 32.5 million pounds, or approximately $100 million.


I became interested in this offshore aqua farming story when I heard that the Catalina Sea Ranch sources their stock from oil rig platforms.  According to hatchery manager, Kelly Stromberg, “these rigs are not only good because they are loaded with mussels, but they also are loaded with our native purple-hinged rock scallops”.  These platform host mussels and scallops that have adapted to thrive in an open water environment, an environment similar to that of the Catalina Sea Ranch, making the oil rig platforms the perfect source for brood stock. Stromberg and her team use this brood stock to breed shellfish on shore, allowing the larvae to develop before bringing them out to the Catalina Sea Ranch to grow to maturity. Once at the Ranch, with the buoys and shellfish in place, the ocean takes care of much of the rest. “Shellfish are low maintenance; once they are out of the hatcheries you don’t have to feed them because they feed off of the natural phytoplankton in the water,” Stromberg said.

The Catalina Sea Ranch is innovating aquaculture, meeting California’s increasing demand for shellfish while also managing valuable ocean resources for a sustainable future. To learn more, visit the Catalina Sea Ranch website.

Changing Planet


Meet the Author
Amber is an oceanographer, conservation biologist and explorer for National Geographic Ocean Views. If she's not diving oil rigs around the world, you can find her in silicon valley developing imaging technology, in collaboration with Google, to facilitate the intersection of ocean science and public awareness.