Breeding a Lifeline for Endangered White Abalone - The Conservation Value of Aquaculture
Juvenile abalone eat small algal species called diatoms (the brown specks in this photo). This 49-day-old white abalone's gut (under the rear part of its shell) is full of diatoms. Its shell is about 0.5 mm long, the size of a fine mechanical pencil tip. (Credit: Kristin Aquilino, UC-Davis)
As part of the health protocol for white abalone that are transferred between captive holding facilities, these are being treated for the removal of shell-boring organisms by applying paraffin wax to the animals' shells. Pictured from left to right are Susan Wang (NMFS Southwest Regional Office), Dr. James Moore (California Department of Fish and Game and BML), and Steve Blair (formerly of the Aquarium of the Pacific).
An adult white abalone being weighed prior to a May 23, 2012 spawning attempt at the Cabrillo Marine Aquarium in San Pedro, California.
August 27, 2012
White abalone used to number in the millions off the southern California coast, but their numbers have declined to the point that, in 2001, they became the first marine invertebrate to be listed as endangered under the Endangered Species Act. Recovery efforts, including closing the fishery in 1997, have not led to an increased population; in fact, trends indicate that this species is approaching extinction.
NOAA Fisheries is working to change that. Aquaculture techniques such as captive breeding can be an effective tool to support populations of imperiled species. NOAA and its partners are supporting a captive breeding program at the University of California - Davis’s Bodega Marine Lab. Using aquaculture techniques, the program seeks to reliably produce captive-bred animals that will be used to establish a self-sustaining population in the wild.
Abalone (Haliotis sorenseni) are a sessile species, meaning that they do not move about in the ocean, and are broadcast spawners, meaning that they release eggs and sperm into the water where fertilization occurs externally. At their current low densities, the animals are too far away from each other to effectively reproduce. The latest population assessment in 2010 indicated that the white abalone population has declined by 78 percent over the last 10 years.
Overcoming Obstacles
After initial success of the breeding program in the early 2000s in which tens of thousands of abalone spawned, the program encountered setbacks related to the health maintenance of the captive-bred animals. However, the program made great advances in disease research and treatment, resulting in better guidelines for water quality, quarantine protocols, and transfer procedures. By adapting aquaculture techniques to overcome these challenges, the program has had increased success in producing healthy juveniles. Scientists recently achieved the first successful spawning of white abalone in over a decade.
As a result, thousands of juvenile white abalone currently reside within settlement tanks at the Bodega lab. In 2011, the lab assumed responsibility as the lead entity for the captive propagation and enhancement program. NOAA’s Office of Aquaculture recently committed $25,000 to ensure that research continues, adding to the primary funding support the NOAA Fisheries Office of Protected Resources has provided for over a decade.
Partners
The program enjoys wide support among a variety of collaborators, giving hope for the future of the endangered white abalone. Partners include federal agencies (NOAA Fisheries Service, National Park Service, Channel Islands National Marine Sanctuary), state agencies (California Department of Fish and Game), universities (University of California - Santa Barbara & Davis, University of Southern California, University of Washington, Scripps Institution of Oceanography), aquaria (The Aquarium of the Pacific, the Cabrillo Aquarium, the Ty Warner Sea Center), and non-profits (Channel Islands Marine Resources Institute).
