Chemicals Induce Abalone to Become ‘Broadcast Spawners' in Bodega Bay

In an effort to try and save the world’s diminishing population of critically endangered white abalone, a Bay Area laboratory hosted a spawning event — which in a single day potentially bred more white abalone than exist in the ocean.

On a recent day, the Bodega Marine Laboratory in the Sonoma County town of Bodega Bay buzzed with the excitement as researchers prepared for breeding day, an event that it’s held once a year over the last few years.

Inside a crowded lab the stars of the day — dozens of adult white abalone — sat in white buckets ready to do their thing. In what would normally seem an impediment to the miracle of procreation, the females and males were segregated to their own buckets — a nod to their peculiar breeding habits in the wild.

“Abalone are called ‘broadcast spawners,’” said researcher Kristin Aquilano who lead the event. “So they send their egg and sperm into the water column and those eggs and sperm have to find each other in the water.”

Inside each plastic bucket, researchers poured a chemical that tricked the abalone into thinking other creatures were spawning in their vicinity. Under the influence of the chemically induced peer-pressure, the males began to release sperm into the water and the females released eggs. Each release of eggs sent a stream of greenish liquid from the female abalone and cued the normally demure scientists to let out a collective cheer.

“We get really excited every time our animals spawn,” Aquilano said.

The scientists extracted the eggs and sperm from the buckets and combined them in a plastic container which they gently stirred and agitated with a small plunger. By the afternoon, the lab’s containers held millions of eggs — with one particularly fertile female alone kicking-in more than 10 million eggs.

Aquilano said that because challenging survival rates, the millions of eggs would likely only result in thousands of baby abalone. Still, she called the one-day baby boom a big success.

“This has been one of the most successful spawnings that we’ve had to date,” Aquilano said.

White abalone were once a popular seafood delicacy — which proved their undoing. In the 1970s they were overfished, dropping their numbers in the wild to what scientists estimate is currently a grim five-thousand, mainly in waters off Southern California. Researchers estimate the Bodega Marine Laboratory’s population of wild abalone is even higher than the entire estimated wild population.

“I think this is for the first time an opportunity to actually have a recovery of a critically endangered species in the marine environment,” said lab director Gary Cherr.

Cherr said the biggest hurdle in the ocean was that the smattering of white abalone were spread too far apart, making it impossible for them to breed. He said the scientists hope to address the problem by repatriating the lab-bred population in the ocean.

“We feel that if we can get them to a certain level of numbers,” Cherr said, “and they’re close together that they will naturally reproduce.”

Cherr said continued breeding efforts could help the wild population rebound in a decade, and maybe even someday lead to a limited fishery.

“We think if we can put enough out there,” Cherr said, “we’ll actually have some success.”

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