California Sea Grant College Program

In October 1993, growers at some commercial abalone mariculture facilities (AMFs) in Southern California brought an interesting sabellid polychaete to our attention.

The worm infested shells of cultured red abalone, Haliotis rufescens. Heavily infested abalone ceased growth. Their shells exhibited domed teratology often lacking respiratory holes. The worms appeared to bore into the shell.

We discovered that all AMFs in California were infested; several were so heavily infested that domed specimens were abundant. The objectives of our study were to describe the worm (Associate principal investigator, K. Fitzhugh, Los Angeles County Museum of Natural History), investigate transmission to abalone, its mechanism of attachment and the cause of shell damage. We also examined the host specificity among common intertidal molluscs. In the course of our research we discovered that a natural rocky intertidal site at Cayucos, California had become infested. Here we sought to investigate how the worms had escaped into the adjacent facility, determine whether the worms had become established there, quantify transmission at that site and devise and supervise an eradication plan.