Invertebrates of Interest: Abalone

The poor condition of red abalone populations led the California Fish and Game Commission to close the fishery in 2018. California Department of Fish and Wildlife (CDFW) surveys in 2018 found lower densities of abalone and numerous fresh empty shells which indicated continued high mortality. The Commission extended the closure until 2021 at their December, 2018 meeting. Subsequent surveys found red abalone populations remained in poor condition and the closure was extended to 2026 at the December, 2020 Commission meeting.

The CDFW does not have an estimate of when the red abalone fishery will reopen, but it is likely that sales of abalone cards will be limited when the fishery resumes. The condition of abalone populations is very poor, and it will probably take a long time before abalone populations could support past levels of fishing. Recent reports of abalone or fresh shells washing ashore during winter storm wave events indicate that mortality is still high. It is very unlikely a fishery would be reopened while abalone populations continue to decline. The circumstances under which the fishery can be reopened will be determined through action of the Fish and Game Commission, pursuant to a new Red Abalone Fishery Management Plan (RAFMP) currently being developed by the CDFW. Information on the RAFMP, including opportunities for public comment, can be found on the RAFMP webpage.

The CDFW has spearheaded the development of the Kelp Ecosystem and Landscape Partnership for Research on Resilience (KELPRR) which provides opportunities for public participation in recovery efforts. KELPRR members with websites providing information on kelp recovery and volunteer opportunities include the Greater Farallones Association, the Noyo Center for Marine Science and the Watermen’s Alliance. This broad partnership of stakeholders, scientists, and resource managers will be developing solutions to help kelp forest ecosystems survive impacts of climate change. The KELPRR program will conduct scientific studies to produce management strategies for healthy kelp forest ecosystems. KELPRR partners are currently working to reduce the effects of widespread loss of bull kelp forests over the past few years in northern California and impacts on north coast fisheries. The recovery of the bull kelp is the first step in recovery for species impacted by kelp deforestation, such as red abalone. Kelp recovery has become such a concern that the California State Senate requested a report (PDF) on the issue and what might be done about it.

Go to the FGC website and request to be put on the list to receive regulation notices for abalone.

The sexes are separate but have similar external appearance. The gonads are the prominent, crescent-shaped end of the internal organs. Ovaries are dark green and testes can be cream, light brown, light green or pinkish in color. Abalone release eggs or sperm through the open holes in their shells. For effective fertilization, abalone need to be within a meter of each other. When abalone are too far apart, their eggs do not become fertilized. Fertilized eggs develop into larvae which can be carried by currents for about a week. The larvae settle to the bottom and develop into very small versions of adults.

Most male red abalone start to reproduce when they are 4 inches in length and 5 years in age. Most females are reproducing at 5 inches in length and 6 years of age. Small females produce far fewer eggs than larger females; a 5 inch female produces about 300,000 eggs while females larger than 7 inches produce about 2,500,000 eggs. Although abalone produce large numbers of eggs and sperm, reproductive success is very sporadic. The last major successful reproductive period for northern California red abalone was probably in the late 1980s.

In recent years, purple sea urchin populations have greatly increased along the northern California coast and have made the main foods for abalone (kelp and other seaweeds) so scarce that many abalone have starved to death. The increased number of shells washing ashore indicates the extent to which abalone populations are being impacted by lack of food. It has also been common to find abalone which have very shrunken bodies due to lack of food rather than a disease (see abalone disease question in FAQ). The shrunken abalone are weaker than healthy abalone and are more likely to be dislodged and killed by large waves.

Abalone are relatively slow growing. Tagging studies indicate northern California red abalone take about 12 years to reach 7 inches but growth rates are highly variable. Abalone grow nearly one inch per year for the first few years and much more slowly after that. It takes about 5 years for red abalone to grow from 7 inches to 8 inches. At 8 inches, growth rates are so slow it takes about 13 years to grow another inch. Slow growth makes abalone populations vulnerable to overfishing since many years are needed to replace each abalone taken.

Withering Syndrome (WS) was very significant in reducing black abalone populations in Southern California during the 1980s-1990s. The rickettisal bacterium that causes WS can infect all California abalone species but each reacts differently to infection. Green abalone appear to be more resistant to the disease than red or black abalone. CDFW biologists found that WS is much more pronounced at higher temperatures such as those experienced in Southern California during the summer. The agent of WS is now present as far north as southern Sonoma County, but the disease has not occurred there because cold water temperatures keep the bacterium in check. Elevated water temperatures associated with global climate change could make WS a threat for northern California red abalone in the future.The CDFW pathology laboratory has determined that all the shrunken northern California red abalone examined were not affected by WS and the shrinkage was due to starvation and the lack of food.

Abalone hatchery efforts in Southern California were not economically feasible. Caring for young abalone is expensive and abalone released from hatcheries had very poor survival rates. Some studies indicated that hatchery-reared abalone did not develop behaviors needed to avoid predators. Abalone from hatcheries can also pose a danger by spreading diseases or parasites. Abalone hatcheries are carefully regulated to eliminate infestations of several known diseases (including Withering Syndrome) and parasites. Out-planting hatchery-reared abalone to enhance abalone stocks is more conducive for recovering severely depleted wild abalone populations to prevent species extinction. The federal and California recovery programs for the endangered white abalone are currently using this technique to save the species from extinction.

The development of Fishery Management Plans (FMPs) is governed by the Marine Life Management Act (MLMA). The MLMA guides CDFW in the conservation and sustainable use of California's living marine resources. The MLMA states that FMPs "shall form the primary basis for managing California's sport and commercial marine fisheries." CDFW is currently in the process of transitioning current abalone fishery management from the Abalone Recovery and Management Plan (ARMP) to a FMP under MLMA guidelines.

The new FMP will focus on management for the sport red abalone fishery in northern California. It is a planning document that contains all the necessary information to make informed decisions to sustainably manage the species while allowing harvest opportunities.

On our website you can find information on public input opportunities, additional literature and reports, public meeting announcements and overview of past meetings.

Both lack of kelp and crowding by purple sea urchins negatively affect abalone populations. In recent years, there have been unusually warm ocean temperatures which have caused poor growth of kelp and other seaweeds and greatly reduced the amount of food for abalone and sea urchins. Lack of food can cause abalone to die from starvation or to be weakened and reduce their ability to survive predators or strong waves. Lack of kelp greatly reduces the amount of food available for abalone in deeper water and may cause them to move into shallower water where they can be caught in the fishery.  Movement to shallow water will make abalone seem more abundant, but the population will be more vulnerable to overfishing. The presence of large numbers of purple sea urchins reduces the amount of food and living space for abalone. When in large numbers, sea urchins can create barrens by eating kelps and seaweeds before they have a chance to grow. Sea urchins are able to withstand starvation conditions and can maintain barrens for many years but abalone cannot survive in barrens. This article provides more information on this issue.