Abstract
The highly dynamic nature of the marine environment can have a substantial influence on the foraging behaviour and spatial distribution of marine predators, particularly in pelagic marine systems. However, knowledge of the susceptibility of benthic marine predators to environmental variability is limited. This study investigated the influence of local-scale environmental conditions and large-scale climate indices on the spatial distribution and habitat use in the benthic foraging Australian fur seal (Arctocephalus pusillus doriferus; AUFS). Female AUFS provisioning pups were instrumented with GPS or ARGOS platform terminal transmitter tags during the austral winters of 2001–2019 at Kanowna Island, south-eastern Australia. Individuals were most susceptible to changes in the Southern Oscillation Index that measures the strength of the El Niño Southern Oscillation, with larger foraging ranges, greater distances travelled and more dispersed movement associated with 1-yr lagged La Niña-like conditions. Additionally, the total distance travelled was negatively correlated with the current year sea surface temperature and 1-yr lagged Indian Ocean Dipole, and positively correlated with 1-yr lagged chlorophyll-a concentration. These results suggest that environmental variation may influence the spatial distribution and availability of prey, even within benthic marine systems.
Highlights
The marine environment is highly dynamic, with substantial variation at multiple spatial and temporal scales [1,2]. Much of this variability has been linked to large-scale climate processes, such as the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation [3,4], that strongly influence the conditions experienced at the local scale
Individuals had a median total distance travelled of 331.7 km (IQR: 291.0 km)
Previous studies have shown that, like in pelagic foraging marine predators [26], the hunting behaviour and diet of benthic foraging AUFS are influenced by environmental variability [24,31,35]
Summary
The marine environment is highly dynamic, with substantial variation at multiple spatial and temporal scales [1,2]. The higher costs to CPF marine predators under reduced prey availability or accessibility can have significant impacts on their reproductive success [13,14]. This is concerning as the balance of phases of large-scale climate drivers are predicted to change over the coming decades [15,16,17,18], with substantial consequences for the distribution and abundance of pelagic species. Benthic systems are considered more stable and, as such, benthic CPF predators have been assumed to have lower susceptibility to environmental variability [19]
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