DIRECT ESTIMATION OF NATURAL MORTALITY OF THE NEW-ZEALAND ABALONE, HALIOTIS-IRIS

Rates of natural mortality (M) of Haliotis iris were estimated by moni toring enclosed populations, and from the frequency of empty marked sh ells recovered from natural populations. Annual instantaneous rates we re less than or equal to 0.1 in all instances. The major source of mor tality was predation by the starfish Astrostole scabra. Predation by f ishes was evidently low. The low rates of natural mortality suggest th at fisheries for H. iris may be less productive than those of other sp ecies of abalone.