Biology

All abalones are herbivorous, and use their large, rough, file-like 'tongues' (radulas) to scrape pieces of algae and other plant material from rock surfaces, as well as feeding on loose pieces of algae and phytoplankton drifting in the water (2) (4). Sea urchins compete with the abalone for food and space, and usually win. Abalone are also key prey for predators such as octopus, crab, lobsters, starfish and sea otters (2). The northern abalone is generally dioecious (separate male and female individuals), although some hermaphrodites (individuals with both male and female reproductive organs) have also been recorded. Sexual maturity is typically reached at 50 mm in length, after about three years of age (2). Spawning, which requires temperatures between 10 and 14ºC, takes place from April to August, when all the male and female abalone in the area simultaneously release their gametes into the water (2) (7). A female abalone can release up to three million eggs, but less than 1% of the offspring are likely to survive to maturity (2) (4). The larvae drift with the currents for about a week before settling to the bottom and developing the adult shell form (4) (5).