Working to Recover Abalone Species to Kelp Forests in the Santa Monica Bay
The kelp forests of Santa Monica Bay once teemed with seven species of abalone—red, pink, green, white, black, pinto, and flat. Through overharvesting in the past century, loss of kelp habitat, and disease, all seven species found in southern California have been nearly wiped out.
As the primary sea urchin competitor, these large underwater snails play an important role in maintaining healthy kelp ecosystems and have been sought after by Californians for their cultural and economic importance throughout history.
Unfortunately, overharvesting and disease led to significant decreases in abalone populations during the end of the 20th century. In 1997, commercial fisheries for all species were closed in California and only one highly restricted recreational fishery for red abalone was permitted north of San Francisco Bay. This northern recreational fishery was closed in late 2017 as urchin barrens emerged along the north coast and abalone died from starvation.
Project Highlights
Progress to Date
- Construction of two aquaculture laboratories
- Improved spawning techniques
- Improved husbandry techniques
- Outplanting of 2,707 juvenile red abalone
- Outplanting of 3,601 juvenile white abalone
- Outplanting of 112,000 larval red abalone
- Outplanting of 863 juvenile green abalone
The Decline of Wild Abalone Populations in the Santa Monica Bay
Abalone populations in the Santa Monica Bay were once numerous, supporting both an active fishery and a thriving kelp forest. Overfishing, however, reduced abalone densities to low levels, preventing the animals from reproducing. Despite fishery closures for the past 20 years, wild populations of abalone have not increased on their own. The low population densities of abalone, in combination with warming waters, disease, increased competition from urchins, and kelp forest loss, have made it difficult for abalone to recover without direct restoration efforts. Therefore, TBF has been working since 2010 to recover abalone populations to the kelp forests of the Santa Monica Bay as a part of a statewide effort to restore abalone populations to their natural levels.
Culturing and Researching Abalone to Support Restoration of the Federally Endangered White Abalone
The White Abalone Recovery Project (WARP) is a statewide collaboration dedicated to the restoration of the federally endangered white abalone to the rocky reefs of southern California. As part of this effort, TBF actively participates in the captive breeding and grow out of both red and white abalone at two separate aquaculture labs. TBF has used red and green abalone as proxies for white abalone, allowing researchers to develop and refine infrastructure, improve culturing and outplanting techniques, and evaluate habitat suitability, while simultaneously restoring all species to local rocky reefs. Additionally, research regarding green abalone deck spawning, red abalone larval spawn and feeding, and more are conducted to improve the understanding of restoring these species.
Outplanting and Monitoring Juvenile and Larval Abalone
After growing to the appropriate size in the aquaculture labs, juvenile abalone are counted, measured, tagged, and placed in enclosures to be outplanted in the coastal waters of the Santa Monica Bay. TBF divers and partners provide these abalone with food and protection, before releasing the animals from the enclosures after their acclimation period. In addition to juvenile abalone, TBF also outplants larval abalone. Both juvenile and larval animals are released into suitable habitat that will promote their capability to thrive and reproduce in the future. TBF continues to monitor these outplanted animals after their release, ensuring their viability and quantifying success in the process.
Progress to Date
- Construction of two aquaculture laboratories
- Improved spawning techniques
- Improved husbandry techniques
- Outplanting of 2,707 juvenile red abalone
- Outplanting of 3,601 juvenile white abalone
- Outplanting of 112,000 larval red abalone
- Outplanting of 863 juvenile green abalone
The Decline of Wild Abalone Populations in the Santa Monica Bay
Abalone populations in the Santa Monica Bay were once numerous, supporting both an active fishery and a thriving kelp forest. Overfishing, however, reduced abalone densities to low levels, preventing the animals from reproducing. Despite fishery closures for the past 20 years, wild populations of abalone have not increased on their own. The low population densities of abalone, in combination with warming waters, disease, increased competition from urchins, and kelp forest loss, have made it difficult for abalone to recover without direct restoration efforts. Therefore, TBF has been working since 2010 to recover abalone populations to the kelp forests of the Santa Monica Bay as a part of a statewide effort to restore abalone populations to their natural levels.
