Shelf-oceanic dynamics of surface environmental parameters in the Kangaroo Island-Bonney Coast region

The shelf and oceanic waters of the Kangaroo Island–Bonney Coast region are important foraging habitats for top marine predators in the ecosystem; however, the dynamics between the two distinct water types have not been investigated. This study examined the spatial and temporal variability of oceanographic parameters in the southern waters of Australia (36–43°S, 136–141°E) associated with the Bonney Upwelling (shelf) and subtropical front (STF; oceanic). Using satellite data from 1997 to 2016, we found that productive oceanic waters were associated with the STF and eddy activity; they were generally furthest from the shelf break in spring–summer (upwelling season on the shelf) and closest to the shelf break in winter–autumn (downwelling season on the shelf). Inter-annual variabilities of chlorophyll-a concentration (Chl-a), sea-surface temperature and sea surface-height anomaly were generally higher in summer than in winter for both shelf and oceanic waters. El Niño–Southern Oscillation, Southern Annular Mode and Indian Ocean Dipole were cross-correlated with anomalous shelf and oceanic Chl-a at various lagged times (range = 15–0 months). This study provides a regional perspective of the spatial and temporal oceanographic variability in southern Australian waters, which may help with understanding apex-predator ecology in the ecosystem.