BODEGA BAY — The stacks of white, water-filled troughs in a small building at the UC Davis Bodega Marine Laboratory offer a bright spot in a landscape of often-grim news about California’s marine environment.
Roughly 2,000 tiny white abalone almost a year into life here represent the promise that an all-but-extinct sea mollusk might survive.
The product of a 4-year-old program that began with 18 wild white abalone plucked from the ocean depths near the Channel Islands 15 years ago, these small shellfish — from pencil-point- to almond-sized — are proof that captive breeding can work. Already, descendant abalone produced over three spawning seasons in affiliated science labs across the state are nearly equal in number to those believed to remain in the wild, where they are scattered so widely they no longer reproduce.
But with greater success in the lab each season, and a new round of spawning planned in early March, scientists in the program say they are just a few years away from beginning to test the survival of the young abalone out at sea, in hopes of eventually restoring some portion of the wild population.
“We may not bring it back anywhere close to what it was,” said Gary Cherr, director of the Bodega Marine Lab and principal investigator for the white abalone captive breeding program. “But if we can establish some self-sustaining populations up and down the coast … that would be a first. That would be really remarkable.”
Unlike their more abundant cousins, the red abalone — which have faced challenges, though their recreational harvest is still permitted off the North Coast — white abalone have existed mainly south of Point Conception, near Santa Barbara, in deep, cold water.
One of five abalone species, they are not white at all, but are considered the tenderest, most delectable of the species, and in 2001 became the first marine invertebrate to be listed under the Endangered Species Act, primarily due to overfishing, scientists said.
More than 280 tons of white abalone were harvested in the 1970s, according to the National Oceanic and Atmospheric Administration. By the late 1990s, the species’ numbers had plummeted.
Recognition of the dire status came so late that it prevented much research on white abalone habits in the wild, reproductive and otherwise.
When a crew of scientists went out in 2000 to collect some for breeding, they deployed a remote-operated vehicle with a mounted camera to search the deep, rocky reefs, targeting “the hottest spots we knew about,” said Laura Rogers-Bennett, who participated and remains a program leader. It took two boats a week to find 18 abalone.
“The picture really has not changed since 2001,” Rogers-Bennett said, adding that a 14 percent mortality rate and inability to reproduce means the wild population is projected to drop below 1,000 in about a decade, give or take a few years. “That’s really a very low number.”
The wild white abalone population is on a downhill slide because abalone are “broadcast spawners” — meaning they release sperm and eggs into the water around them — and therefore rely much on density to successfully reproduce.
“There’s probably a few thousand left in the wild,” said Kristin Aquilino, a post-doctoral student who manages the breeding program. “But because they’re so far apart, they’re effectively sterile. Their population could be effectively extinct already.”