Nl. Andrew et Aj. Underwood, ASSOCIATIONS AND ABUNDANCE OF SEA-URCHINS AND ABALONE ON SHALLOW SUBTIDAL REEFS IN SOUTHERN NEW-SOUTH-WALES, Australian Journal of Marine and Freshwater Research, 43(6), 1992, pp. 1547-1559
The densities of the abalone Haliotis rubra and the sea urchin Centros
tephanus rodgersii were estimated at five localities on the southern c
oast of New South Wales. Abalone were most abundant at localities sout
h of Eden but were patchy at all localities and sites. There was no cl
ear pattern in the abundance of C. rodgersii among localities but ther
e was considerable variation among sites within localities. Densities
of abalone and sea urchins were negatively associated within 10-m2 tra
nsects at 20% of sites. At the smallest nearest-neighbour scale, the t
wo species were segregated. The population structures of abalone diffe
red considerably among sites; some populations consisted of single siz
e cohorts, whereas others were much more complex. Abalone large enough
to be collected legally were rare at all localities and comprised les
s than 10% of the total population. Possible reasons for the negative
associations between H. rubra and C. rodgersii are discussed.