It is widely recognised that abalone fisheries consist of numerous populations with variable life history parameters. Current broad-scale management regimes do not account for this variation and can lead to serial depletion of separate populations. However, the ability to manage abalone populations at fine scales is limited by our knowledge of the scale at which abalone ‘populations’ exist.

Morphometric data collected from 8- broad and 8 fine-scale sites in the Southern Zone Abalone Fishery of South Australia (SZ), suggest that a shell length/shell height ratio can discriminate among populations that show ‘stunted’ and ‘non-stunted’ patterns of growth. Moreover, biological information collected in conjunction with the morphometric data revealed that the spatial variability of this ‘morphometric marker’ was highly correlated to that of growth and reproductive biology. The ‘morphometric marker’ was applied to commercial shell samples collected across the SZ to identify the spatial distribution of ‘stunted’ and ‘non-stunted’ populations. Several decision rules were used to identify how this information could be used to potentially alter current management arrangements in the SZ.