Predation by polychaete worms on larval and post-settlement abalone Haliotis iris (Mollusca:Gastropoda)

Abstract

Predation on post-settlement abalone ( Haliotis iris) by polychaete worms inhabiting the crusts of non-geniculate coralline algae was examined experimentally. In the subtidal habitat of H. iris, the warty Mesophyllum printzianum supported dense assemblages (> 0.5 cm −1) of the cirratulid Dodecaceria berkeleyi and the spionid Boccardia chilensis, but few polychaetes were found in the encrusting Spongites yendoi. Survival rates for inocula of hatchery-reared larvae of H. iris ( n = 10) on experimental substrata ( M. printzianum) were 29.0 + 9.2% with D. berkeleyi, and 52.4 + 10% with B. chilensis after a 24 h trial. There was no significant density effect (1–4 individuals per 10 cm 2 vs. 6–10 individuals per 10 cm 2) for either species of polychaete. The results indicate that refugia from water currents and piscivorous predators offered by coralline surfaces are offset by the biological hazards associated with resident infaunal predators. This interaction will determine levels of recruitment of abalone and other benthic invertebrates to coralline surfaces.