Growth and demography of paua Haliotis iris (Mollusca: Gastropoda) in northeastern New Zealand

The growth and demography of an unfished population of paua (Haliotis iris) was examined within a marine reserve on the northeastern coast of New Zealand from 1986 to 1991. Size-frequency analysis showed that recruitment of paua was regular and annual. Paua were found and measured in the field down to 4 mm shell length and juvenile paua were individually tagged down to 8 mm shell length. Growth estimates from tag-recapture and size-frequency analysis revealed that paua grew rapidly to a size of at least 70 mm shell length in approximately 3 years. Growth then slowed abruptly with negligible growth beyond 80 mm. In contrast to studies in other areas, paua rarely reached the legal takeable size of 125 mm. Tag-recapture studies revealed large variability in growth of the juvenile paua. The differences in growth and demography between southern and northern populations of paua has important implications for the future management of northern paua populations.