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To detect and monitor long-term ecosystem responses to environmental variability, managers must utilize reliable and quantitative techniques to predict future ecosystem responses. Canine teeth from 67 male Australian fur seals (aged 2–19 yr), collected at Seal Rocks, between 1967 and 1976, were measured for relative growth within the dentine growth layer groups (GLGs), as an index of body growth. Fluctuations in relative growth were apparent during 1956–1971, suggesting interannual variation in prey resources within Bass Strait. These were positively correlated with the Southern Oscillation Index and negatively with the Indian Ocean Subtropical Dipole, both on a 2 yr lag. The observed delay may reflect the time required for the nutrient cascade to filter through to the predominantly benthic prey of Australian fur seals. Stable isotope analysis (δ15N/δ13C) was also used to investigate whether fluctuations in growth were associated with differences in diet. Relative growth was found to be negatively correlated with δ15N, suggesting years of greater resource availability may be associated with individuals consuming proportionally more prey biomass of lower isotopic value. This study demonstrates that fluctuations in the dentine GLGs of male Australian fur seals are related to environmental parameters, suggesting variation in body growth is mediated by changes in prey resources.

To examine the factors influencing birth site selection and territory location in Australian fur seals (Arctocephalus pusillus doriferus), habitat variables (slope, substrate, and elevation) were quantified in seven zones within a breeding colony on Kanowna Island (39o15′S, 146o18′E), southeastern Australia. Distribution across the colony was not uniform with zones at low elevations (i.e., close to water) being preferred areas, having earlier occupancies and greater female densities. Body length of females and territorial adult males was assessed using laser-metrics. Average female length increased throughout the breeding season, within zones and across the colony, with larger females arriving to give birth later. Larger females also occupied areas of lower elevation close to water. Adult male body length had no influence on territory size, but was positively correlated with the number of females in harems (r2 = 0.70, P