Biology

This sessile mollusc uses its foot to clamp tightly to a rock, where it feeds on algal matter scraped from the rock surface, and catches drifting algae with its tentacles. Juveniles tend to reside in crevices to reduce their risk of predation, but the larger adults will move out onto rock surfaces. They may still be preyed upon by fish and otters (1). Between three and seven years old, the black abalone will begin to reproduce. In a perfectly synchronised release of eggs and sperm amongst all the abalones in one area, fertilisation occurs, resulting in tiny free-swimming larvae. After 15 days, the larvae metamorphose into their adult form, develop a shell and settle onto a rock. They are thought to be able to live for between 25 and 75 years, and will begin to reproduce between three and seven years (1).