Shell boring clams in the blue abalone Haliotis fulgens and the yellow abalone Haliotis corrugata from Baja California, Mexico

摘要

The blue abalone Haliotis fulgens and yellow abalone Haliotis corrugata support the major portion of the abalone fishery in Baja California, Mexico. Abalone shells are marketable according to the quality of their shell, which is determined by the quantity and kind of epibionts, such as boring clams. In order to determine the extent of infestation by shell boring clams in these abalone species, shell samples from the commercial catch were obtained from Isla de Cedros, Baja California, and analyzed.Three shell boring species, Lithophaga aristata. Lithophaga plumula and Penitella conradi, were found infesting the blue abalone. The yellow abalone was infested by L. aristata and L. plumula. The prevalence and density of these two species were greaterin the yellow abalone than in the blue abalone. The density of boring clams increased on older and consequently larger abalone shells (greater shell surface), although this trend needs confirmation. X-ray images revealed the severity of shell damage in heavily infested animals. The identification of different fishing areas that provide different quality abalone shell, due to their boring clams load, opens the possibility for determining management regulations for obtaining better shells for marketing.