ORCID Profile
0000-0002-2729-6433
Current Organisations
Department of the Environment, Australian Government
,
Australian Antarctic Division
,
University of Tasmania
,
South Atlantic Environmental Research Institute
,
University of Tasmania Institute for Marine and Antarctic Studies
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Publications
Horizontal-vertical movement relationships: Adélie penguins forage continuously throughout provisioning trips
Publisher: Springer Science and Business Media LLC
Date: 26-08-2021
DOI: 10.1186/S40462-021-00280-8
Abstract: Diving marine predators forage in a three-dimensional environment, adjusting their horizontal and vertical movement behaviour in response to environmental conditions and the spatial distribution of prey. Expectations regarding horizontal-vertical movements are derived from optimal foraging theories, however, inconsistent empirical findings across a range of taxa suggests these behavioural assumptions are not universally applicable. Here, we examined how changes in horizontal movement trajectories corresponded with ing behaviour and marine environmental conditions for a ubiquitous Southern Ocean predator, the Adélie penguin. Integrating extensive telemetry-based movement and environmental datasets for chick-rearing Adélie penguins at Béchervaise Island, we tested the relationships between horizontal move persistence (continuous scale indicating low [‘resident’] to high [‘directed’] movement autocorrelation), vertical e effort and environmental variables. Penguins ed continuously over the course of their foraging trips and lower horizontal move persistence corresponded with less intense foraging activity, likely indicative of resting behaviour. This challenges the traditional interpretation of horizontal-vertical movement relationships based on optimal foraging models, which assumes increased residency within an area translates to increased foraging activity. Movement was also influenced by different environmental conditions during the two stages of chick-rearing: guard and crèche. These differences highlight the strong seasonality of foraging habitat for chick-rearing Adélie penguins at Béchervaise Island. Our findings advance our understanding of the foraging behaviour for this marine predator and demonstrates the importance of integrating spatial location and behavioural data before inferring habitat use.
Spatial overlap between South American fur seal foraging effort and commercial trawl fisheries in the Falkland Islands
Publisher: Elsevier BV
Date: 10-2023
Spatial link between Adélie penguin foraging effort and krill swarm abundance and distribution
Publisher: Frontiers Media SA
Date: 26-01-2023
DOI: 10.3389/FMARS.2023.1060984
Abstract: Understanding how predator foraging behaviour is influenced by the distribution and abundance of prey is a fundamental challenge in marine foraging ecology. This is particularly relevant in Southern Ocean ecosystems where the relationships between select predator species and Antarctic krill ( Euphausia superba ) can inform ecosystem conservation and precautionary fisheries management. In this study, we examine the spatial associations between krill swarm characteristics and Adélie penguin ( Pygoscelis adeliae ) foraging effort at Béchervaise Island, a long-term monitoring site in East Antarctica. Spatially integrating two years of regional-scale krill acoustic data with contemporaneous horizontal and vertical movement information from chick-rearing adult Adélie penguins, we assessed how penguin foraging effort changed in relation to krill swarm abundance and distribution across the survey area. Our findings show that penguin ing effort was focused in areas with a high number of krill swarms, yet they did not focus their effort in areas with high krill biomass. These results suggest the spatial organisation of Adélie penguin foraging effort can provide an indication of krill presence (and/or availability) but may not reflect krill abundance. We discuss our results in the context of penguin foraging strategies, capturing single krill within the water column rather than the engulfment feeding strategy of larger marine mammals such as whales. Our work substantially improves understanding of penguin-krill dynamics in East Antarctica and provides a greater level of nuance regarding the utility of Adélie penguins as indicator species under CCAMLR’s Ecosystem Monitoring Programme (CEMP). Understanding these predator-prey linkages will become increasingly important for managing any expanding krill fisheries in the region or changes in the prey field under future climate change scenarios. Thus, our results can be interpreted alongside other ecological indicators to support management of the East Antarctic sector of the Southern Ocean ecosystem.
Stomach content analysis of mesopelagic fish from the southern Kerguelen Axis
Publisher: Elsevier BV
Date: 04-2020
From trips to bouts to dives: temporal patterns in the diving behaviour of chick-rearing Adelie penguins, East Antarctica
Publisher: Inter-Research Science Center
Date: 12-11-2020
DOI: 10.3354/MEPS13519
Abstract: Breeding Adélie penguins forage at sea and return to land to provision their chicks, adjusting their foraging behaviour in response to environmental fluctuations over time. At Béchervaise Island, a nesting site in an East Antarctic population, Adélie penguin ing behaviour remains undocumented. This represents a key area of uncertainty in efforts to understand and predict foraging success at this colony. We compiled a multi-year telemetry dataset from time-depth recorders deployed from 1992 to 2004 on 64 birds at Béchervaise Island. We examined ing activity at multiple scales, ranging from foraging trips (n = 125) to e bouts (n = 3461) to in idual es (n = 84521), and then characterised the stage- and sex-specific variation in ing behaviour of chick-rearing Adélie penguins using linear mixed effect models. Total foraging trip effort (trip duration, number of es, vertical distance travelled and number of wiggles [a proxy for prey ingestion]) substantially increased as the chick-rearing period progressed (guard through crèche), consistent with increasing chick provisioning and self-maintenance requirements over time. Foraging activity was predominantly structured in periods of sustained ing bouts, indicating sustained foraging effort over the course of the foraging trip. Diving behaviour ( e-level depth, duration, bottom time and attempts of catch per unit effort) varied in relation to sex and chick-rearing stage. Dives were performed more frequently during high and low levels of solar light, which is likely linked to visual predation strategies or prey activity. Our findings advance our understanding of this population’s foraging behaviour, which is ultimately required to underpin the conservation and management of this breeding colony.
Related Organisations
Masonic Medical Research Institute
Location: United States of America
Department Of The Environment, Australian Government
Location: No location found
Department Of The Environment, Australian Government
Location: Australia
South Atlantic Environmental Research Institute
Location: Falkland Islands (Malvinas)
University Of Tasmania Institute For Marine And Antarctic Studies
Location: Australia
Related Funding Activities
No related grants have been discovered for Javed Riaz.