Abalone Restoration Update

Researcher:

Thomas B. McCormick.
Channel Islands Marine Resource Institute
E.: t_mccormick@ojai.net
T.: (805) 798-2505

Hunter S. Lenihan.
Bren School of Environmental Science and Management

UC Santa Barbara
E.: Lenihan@bren.ucsb.edu
T.: (805) 893-8629

Relevant Links:

Restoration of Endangered White Abalone: Resource Assessment, Genetics, Disease and Culture of Captive Abalone

Tools:

Revised:

June 27, 2008

A black abalone. Photo: Wikipedia

June 27, 2008

Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334

California Sea Grant researchers have discovered a genetic basis for resistance to the lethal withering syndrome in black abalone, and they have developed husbandry techniques for breeding disease-resistant black abalone in captivity for release in the wild.

“Everything is in place for outplanting to be a reality, except for one major glitch, “ says UC Santa Barbara biologist Hunter Lenihan. The males are not in the mood.

“Our female black abalone are still champs but our males have yet to spawn,” he says. The reproductive challenge is not just about males being shy in captivity, and it is not a black abalone issue only.”

A white abalone jumps onto a kelp blade. Credit: Tom McCormick.

A Mechanism for Dispersal?

In terms of basic science, one of the most exciting discoveries of this project was the observed “standing” behavior of 1- to 3-year-old white abalone when put in a tank with drifting pieces of giant kelp blades. The abalone were observed to raise themselves onto their shell edge to “climb” onto the kelp and to stay attached to these for as long as 51 days, California Sea Grant biologist Tom McCormick reports.

This “rafting” behavior has never been observed for any other abalone species and may explain the wide distribution of white abalone throughout the Southern California Bight. Algal rafting could potentially transport benthic life stages or groups of small abalone far beyond the range of larval dispersal, he says.

“Our surveys up and down the coast indicate very few male black abalone have ripe gonads,” he says.

Tom McCormick of the Channel Islands Marine Resource Institute had planned to release about 150,000 white abalone larvae in the Channel Islands National Park this summer. It would have been the first abalone restocking effort on the West Coast.

“But ah, the agony of abalone,” McCormick says. “During the past two weeks, we tried spawning the white abalone three times. The females performed well each time, giving us over 10 million eggs. The males were less able. Only once did we get a little bit of sperm, but it yielded very low fertilization rates.

“At this point, we have tried spawning all the males at Channel Islands Marine Resource Institute and UC Santa Barbara,” he says.

Like any good fertility clinic, the scientists plan to change the males’ diet. It is also possible that disease, or even disease-resistance, has reduced their fertility.

McCormick, however, suspects that feminizing endocrine disrupting compounds may be to blame. “Endocrine disrupters, such as the Bisphenol A in your plastic water bottle, are being released into the aquatic environment in large quantities, and we really have little idea how they affect the reproductive cycle of many invertebrates.”