Wildlife along San Diego County’s coast is so abundant it’s difficult to miss: sea lions sunbathing on the rocks of La Jolla Cove, gray whales frolicking on their winter journey to Baja California, and the Garibaldi fish, with its radiant orange hue, standing out against the clear blue waters.
But far more species in the region’s major bays, sandy beaches, tidepools, sandstone cliffs, estuaries and ports are missed. And not just by tourists, but also by science.
Across California’s coast, researchers know about 3,000 invertebrate species and about 1,000 algae species. But they believe there may actually be 10 times that amount that have yet to be identified. They just don’t know for sure.
That’s about to change. Scientists are beginning to create a record of the known and undocumented. They said it's California’s first DNA library of species living in intertidal zones, or “the area where the ocean meets the land between high and low tides,” according to the National Oceanic and Atmospheric Administration.
“It gives us a snapshot of what the current diversity is for California in a period when the warming of oceans is going to change their distributions,” said Greg Rouse, who is leading the statewide effort and is a professor at Scripps Institution of Oceanography.
Dubbed the California Intertidal Biodiversity DNA Barcode Library Project, the initiative kicked off in La Jolla on June 21.
The process looks like this: About 50 scientists, students and volunteers from various parts of the country get up early in the morning and visit sites from Imperial Beach to Oceanside.
When they spot larger animals, such as octopuses, lobsters and sea anemones, they take their photograph and collect small tissue samples. For those they cannot see without a microscope, Rouse said they fill buckets with sand or seaweed and search for them in the lab at Scripps.
“We put it under all kinds of microscopes to pick out those little individuals,” he said. “And then the taxonomic experts help us identify what they are.”
It takes experts like Siobhan Braybrook, an algae expert from UCLA whose left arm is adorned with colorful seaweed tattoos, to know where to look and properly identify the varied species. Early Wednesday morning, she collected a sample of articulated coralline algae.
“Their entire shell is sort of made of calcium carbonate, and they’re really stiff,” she said. “They almost look like coral, that’s why we call them corallines.”
The specimens will be stored in research collections, and they'll be “available for researchers for decades to come,” Rouse said.
Most species get DNA barcodes. That will make it easier to identify and protect them. The data could also help researchers better understand changes in the ocean as related to climate change, including where and why animals migrate.
“Some animals are moving up from the south as the warming ocean comes up,” said Rouse. “We're getting species that previously were only known in Mexico. And then there might be animals that will be pushed further north out of California waters.”
DNA barcode libraries aren’t new in California. A similar effort to catalog tens of thousands of insect species living in California, of which the San Diego Natural History Museum has been a part, started in 2023.
But there hasn't been one for intertidal species. In July 2023, Gov. Gavin Newsom approved setting aside nearly $10 million for the intertidal DNA barcode library project.
Additional surveys are planned at sites along the California coast over the next year.
Rouse said he expects “big picture summaries” and other scientific publications about what was found along the coast to come out in the coming years.
