Symbionts of cultured red abalone Haliotis rufescens from Baja California, Mexico

摘要

Although the commercial culture of the red abalone Haliotis rufescens started in Baja California in 1993, no descriptions of the symbionts of this species exist. To determine which symbionts were associated with cultured red abalone in the Bahia deTodos Santos. Baja California, we conducted a survey of apparently healthy and moribund abalone. Apparently healthy abalone were larger (34 mm) than the moribund abalone (25 mm). Two polychaetes belonging to Spionidae and Serpulidae were found on the shell, although no serious damage was observed in relation to these worms. The renal coccidian Margolisiella (= Pseudoklossia) haliotis, was prevalent in 72 percent of the moribund and 10 percent of apparently healthy abalone. Rickettsiales-like prokaryotes(RLPs) associated with the withering syndrome (WS) were found in the epithelia of the digestive gland of all moribund abalone. 84 percent of apparently healthy abalone were also infected with RLP, although no clinical signs were observed. Ciliate protozoa were observed in the lumina of the esophageal pouches of both apparently healthy (78 percent prevalence) and moribund animals (57 percent prevalence). Other ciliates were observed on branchia and within the branchial cavity of apparently healthy abalone (17 percent) and moribund abalone (88 percent prevalence). Although there was a trend for greater prevalence and intensity of symbionts in moribund compared to apparently healthy abalone, the differences were not significant.