Population dynamics and fishery management of the New Zealand paua, Haliotis iris. I. Population structure, growth, reproduction and mortality
Sainsbury, K, Population dynamics and fishery management of the New Zealand paua, Haliotis iris. I. Population structure, growth, reproduction and mortality, New Zealand Journal of Marine and Freshwater Research, 16, (2) pp. 147-161. ISSN 0028-8330 (1982) [Refereed Article]
The biology of an unfished population of the paua, H. iris Martyn, in Peraki Bay, Banks Peninsula New Zealand, was studied from 1973 to 1976. In Feb., 1976, the population consisted of .apprx. 179,000 animals on 4.5 km of coastline. The length/frequency distribution was strongly skewed to the left, indicating an accumulation of old individuals and a recent history of low recruitment. Growth of animals < 70 mm long was determined from changes in length frequency, and of larger animals by the analysis of tag returns. The mean parameters of the von Bertalanffy growth equation for the study population are K = 0.163 and L = 131.9 mm. Both are lower than those reported for paua in a more typical habitat near Kaikoura. The annual instantaneous natural mortality rate, as estimated by several methods from population size strucutre and individual growth-rate data, is .apprx. 0.1. Spawning was monitored during the breeding seasons of 4 yr. Spawning on Banks Peninsula failed to occur during 2 yr, and the failure during 1 yr was geographically widespread. No explanation for these spawning failures can be offered. The length at first maturity was the same at Peraki Bay and Kaikoura, despite a much lower growth rate and fecundity at Peraki Bay. Recruitment was 2000-5000 2-yr-old/yr and either recruitment is largely independent of local spawning success or significant spawning occurs outside the currently accepted breeding season.