The scientific literature has generally accepted that abalone populations are characterised by low levels of settlement and recruitment (Tegner in press), that mortality is relatively low (Doi et al. 1977; Beinssen and Powell 1979; Sainsbury 1982; Shepherd et al. 1982; Fournier and Breen 1983) and uniform throughout life (Shepherd et al. 1982), and correspondingly that the natural productivity of these stocks is low (Tegner in press). In some studies it has been noted that one or more year classes are apparently missing (Forster et al. 1982; Sainsbury 1982) and this has led to the conclusion that abalone recruitment is relatively sporadic and irregular. It has been generally assumed that larval dispersal is relatively widespread (20-50km; Tegner & Butler 1985). No relationship had been observed between the abundance of breeding stock and the abundance of recruitment. On the basis of these observations and laboratory studies, together with genera lly held assumptions, it has been accepted that oceanographic and other environmental factors would be the major determinants of settlement and recruitment density (Fedorenko & Spout 1982; Tegner in press).

It was these widely held views which led to the original rationale for this project, which was to develop an index of settlement or recruitment abundance which could be used to predict broad scale trends in the future abundance of the fishable stock.

In addition, there was also no scientifically proven method of ageing abalone prior to this study, and it was generally accepted that the Australian species of abalone could not be aged. The FIRTA-funded review of Ward (1986) found that this was a major impediment of research into and assessment of abalone stocks in Australia.