California officials allow plans for the country’s biggest kelp farm to move forward

California has long been farm country, and its oceans soon could be, too.

State coastal officials voted Wednesday to allow a plan to build the United States’ largest kelp farm 6 miles (10 kilometers) off the Southern California coast to move forward as the Trump administration seeks to ramp up aquaculture in the Pacific Ocean.

Ocean Rainforest, which is based in the Faroe Islands in Northern Europe, is planning to grow giant kelp on a roughly 3-square-mile (7.8-square-kilometer) stretch of federal waters to develop products to boost soil and plant health in California’s avocado farms and strawberry fields. Some environmentalists are concerned that the lines used to grow seaweed could tangle whales and that increased boat traffic will disrupt an expanse of ocean that has been wild.

Ocean Rainforest said it plans to gradually build up the sea farm over a decade and could harvest as much as 6,000 tons of kelp at full capacity, ramping up a U.S. seaweed industry that lags behind Asia despite the country’s extensive coastlines. The plan is to harvest kelp and process it in the port city of Ventura about 60 miles (97 kilometers) northwest of Los Angeles.

“Let’s start in our backyard,” Douglas Bush, Ocean Rainforest’s director of California operations, said in a recent interview. “Let’s grow the seaweed here, let’s process here in California, let’s use it in California farms.”

Farm part of push for aquaculture

The proposal to grow kelp off Ventura County comes as the Trump administration seeks to promote commercial aquaculture. The National Oceanic and Atmospheric Administration last year designated 13 areas totaling 33 square miles (85 square kilometers) for the development of aquaculture off California and Texas. The plan is part of a 2020 push to develop the U.S. seafood industry.

It also comes as the market for seaweed has been growing for uses ranging from restaurant dishes to pet food. Dozens of farms are cultivating different types of seaweed in New England, the Pacific Northwest and Alaska. A World Bank report in 2023 estimated seaweed markets could grow another $11.8 billion by 2030.

Some environmental groups backed the California project, noting seaweed can help absorb carbon dioxide from warming ocean waters and restore habitat while feeding off ocean nutrients.

Environmentalists raise questions

But some raised questions about the impact of hundreds of boat trips a year to maintain and harvest the seaweed and the potential for whales migrating or feeding in the area to get tangled in lines stretching up from the sea floor, or tethered to buoys, to grow the kelp. Ocean Rainforest said no whales got tangled in taut lines during a two-year demo project.

“This is our blue Serengeti. This is a very wild place,” said Geoff Shester, director of fishery innovation at the ocean conservation group Oceana. “It’s like you might as well put a bunch of industrial data centers in Yosemite National Park.”

Cassidy Teufel, deputy director at the coastal commission, said during a review of the project that seaweed farms use taut, rigid lines, not the loose fishing lines that are a leading cause of whale entanglements. The farm will be located further offshore where there’s a lower density of marine mammals, Teufel said.

It is possible the project will draw fish, and sportfishing will be permitted in the area, Teufel said. Some commercial fishing will be displaced, and Ocean Rainforest and fishermen said they are working on an industry support fund.

Under U.S. law, California officials have a say over projects built on federal properties that will affect the state’s coast. The California Coastal Commission voted unanimously to let the kelp farm move forward with conditions including a phased approach. Ocean Rainforest will initially build in a smaller area and face periodic reviews by the U.S. Army Corps of Engineers and the commission’s director before expanding to full capacity.

With the decision, Ocean Rainforest said it has the major approvals needed for the project. Construction could begin in 2027.

The region around Ventura is known for growing strawberries, avocados and other crops.

Ted Travers, chief operating officer of the avocado farm Simpatica, said he was eager to see kelp-based products for agriculture developed on the West Coast. He said in a letter to the commission that all the kelp currently used for agricultural purposes comes from the Atlantic Ocean, “which is financially and environmentally impractical.”

Ventura and port officials welcomed the project as a way to bring new industry and jobs to the city of 100,000 people.