Species in the Spotlight: White Abalone

August 13, 2015 ODU Admin Conservation Comments Off on Species in the Spotlight: White Abalone

Species in the spotlightThe endangered white abalone (Haliotis sorenseni) belongs to an iconic group of herbivorous marine snails that were once plentiful in California kelp forests and that supported a lucrative fishery. Intense commercial harvesting of white abalone began in 1969 and peaked in 1972 at about 143,000 pounds per year. Just 6 years later, the fishing industry caught less than 5,000 pounds. In 1997, California closed all commercial and recreational harvest of abalone except for a highly regulated recreational fishery for red abalone north of San Francisco.

Since 2002, NOAA has conducted research cruises with remotely operated vehicles (ROVs) and SCUBA surveys in the Southern California Bight to monitor abundance of the last known white abalone populations and to characterize their habitat. The number and density of wild white abalone have declined precipitously or remain extremely low at these locations, suggesting that extinction is imminent and natural recovery is not occurring.

Threats
Threats to white abalone include overfishing (historic), reproductive failure, and infections.  Adults do not occur in high enough densities to successfully reproduce.

White abalone are considered “broadcast spawners,” shooting eggs and sperm into the water by the millions when environmental conditions are right. One female can release as many as 10 million eggs at a time, but must be relatively close (on the order of meters, it is thought) to a male for fertilization to occur. Unfortunately the high impact of the fishery diminished the density of white abalone to the point that males and females are not close enough to one another to spawn successfully. Therefore, immediate actions are necessary to reverse the downward abundance trend to prevent the species’ extinction and put it on a path toward recovery.

Recovery
To help avert the likely extinction of the species, a captive propagation and enhancement program was initiated to reintroduce captive-grown white abalone back into the wild. The University of California at Davis’ Bodega Marine Laboratory (BML) oversees the program in close coordination with NOAA Fisheries and in partnership with five other facilities. These efforts are designed to determine whether captive propagation is an effective recovery tool for restoring wild, self-sustaining populations of white abalone. BML and its partners have successfully spawned and reared white abalone each year since 2012, increasing production success and capacity in each successive year. 

Between 2012 and 2014 the number of animals raised to the juvenile stage has increased by three orders of magnitude, resulting in thousands of settled animals in captivity. BML is currently monitoring the growth and survival of these juveniles, has submitted a request to collect additional broodstock to increase the chances for successful future spawning, and is exploring methods for improving reproductive maturation, fertilization rates, and settlement success. Additional spawning attempts will occur during the spring and early summer of 2015. 

Concurrent with captive propagation, NOAA Fisheries is leading efforts with partners to develop innovative methods for outplanting, non-invasive genetic methods for identifying males and females, genomic tools for increasing the fitness potential of captive-raised abalone, non-lethal genetic tagging methods for identifying outplanted abalone, and post-outplant monitoring methods. When the time for reintroducing white abalone comes, these methods and tools will be essential for measuring the survival of outplanted animals and gauging the overall success of the captive propagation and enhancement program.

NOAA Fisheries is developing a 5-year plan of action for this species, which builds on the recovery plan and details the focused efforts that are needed over the next 5 years. We will continue to engage vital partners in the public and private sectors in actions they can take to support this important effort.

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About The White Abalone

LOCATION 

  • Since the mid-1990s, extremely low numbers of isolated survivors have been identified along the mainland coast in Santa Barbara County and at some of the offshore islands and banks in the middle portion of the range, indicating the current range of white abalone in California may be similar to what it was historically.

STATUS

  • A well-studied population in Southern California declined by roughly 78 percent between 2002 and 2010 (from approximately 15,000 to just 3,000 individuals) and will likely continue to decline by approximately 10 percent per year.

HABITAT 

  • White abalone are found in open low and high relief rock or boulder habitat that is interspersed with sand channels. Sand channels may be important for the movement and concentration of drift macroalgae and red algae, upon which white abalone are known to feed. White abalone usually found between at depths of 80-100 feet (25-30 m), making them the deepest occurring abalone species in California.

Check out abalone restoration projects below. 

NOAA and Partners “Planting” Long-Lost Abalone in the Sea
Innovative Abalone Spawning Technique to Aid Restoration 
VIDEO: Pinto Abalone Restoration: Outplanting in March 2011  
Restoring Abalone: The Time is Now

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