Recruitment, growth, mortality and population structure in a southern Australian population of Haliotis rubra (Mollusca: Gastropoda)

A population of Haliotis rubra Leach at Blubber Head in south-eastern Tasmania, Australia (43°19′S; 147°04′E) was sampled between February 1984 and October 1985. Relatively large numbers of 30 to 45 d-old new recruits were observed entering the population between October and February of each year. The annual instantaneous rate of natural mortality, Z, was 0.70 during the second year of life. The rate of natural mortality declined with age. The onset of sexual maturity began at 4 to 5 yr of age or an approximate maximum length of 90 mm, and most abalone in the population were mature at 6 to 7 yr of age or at lengths>110 mm. The onset of sexual maturity coincided with a decline in growth rates and the emergence of abalone from the subboulder habitat. These observations are discussed in the light of previous observations of population structure in haliotid populations