They can be up to 10 inches, but are usually 5-8 inches. If fertilized, the eggs hatch after only one day, but high concentrations of sperm are required in order for an egg to be fertilized. Therefore, aggregations of adults are necessary for successful fertilization to occur. Currently, the white abalone are frequently found alone, and have little chance for successful fertilization. Because populations are only small fractions of former numbers, recovery will be complicated by loss of genetic diversity from genetic bottlenecks, genetic drift and founder effects.
Abalones are also vulnerable to various bacterial and parasitic infections.
The fishery was historically managed using size limits and seasons, but such methods failed because they did not account for density dependent reproduction and assumed regular successful settlement of the larvae. In August 1998, NMFS initiated a status review of the biological status of white abalone. NMFS completed its status review of the species in March of 2000, and that document is available from our website. NMFS published a proposed rule to list the white abalone as endangered on May 5, 2000. Comments were accepted until July 5, 2000.