At-sea movements and habitat use of adult male Australian fur seals (Arctocephalus pusillus doriferus)

2006 ◽  
Vol 84 (12) ◽  
pp. 1781-1788 ◽  
Author(s):  
Roger Kirkwood ◽  
Michael Lynch ◽  
Nick Gales ◽  
Peter Dann ◽  
Michael Sumner
Keyword(s):  
Habitat Use ◽  
Continental Shelf ◽  
Adult Male ◽  
Maximum Distance ◽  
Commercial Fisheries ◽  
Southeastern Australia ◽  
Foraging Area ◽  
Fur Seals ◽  
Water Columns ◽  
Foraging Ranges

Foraging by adult male otariids, a demographic component that often interacts with commercial fisheries, are poorly known. To assess movement patterns and habitat use, nine adult male Australian fur seals ( Arctocephalus pusillus doriferus Wood Jones, 1925) from Seal Rocks, in northern Bass Strait, southeastern Australia, were tracked for periods ranging from 66 to 223 d during 1999–2001. Mean ± SD at-sea and on-land durations were 6.9 ± 2.1 d (range 2.3–10.3 d, n = 9 seals) and 2.4 ± 0.9 d (range 0.8–4.1 d), respectively. All seals foraged almost exclusively in continental shelf waters and mostly (65%–97% of time at sea) in water columns that were between 40 and 100 m deep. Six of nine seals tracked for >30 d spent 64%–98% of their time-at-sea foraging at distances <200 km from Seal Rocks, although the maximum distance achieved from the colony was 1208 km. The seals’ foraging ranges overlapped with the ranges of operation of virtually all fin-fish fisheries in southeastern Australia, but fisheries overlap was low in the most frequented foraging area of central-western Bass Strait.

scholarly journals Dive behaviour, foraging locations, and maternal-attendance patterns of Australian fur seals (Arctocephalus pusillus doriferus)

2001 ◽  
Vol 79 (1) ◽  
pp. 35-48 ◽  
Author(s):  
John PY Arnould ◽  
Mark A Hindell
Keyword(s):  
Continental Shelf ◽  
Diel Variation ◽  
Sea Lion ◽  
Dive Behaviour ◽  
Southeastern Australia ◽  
Attendance Patterns ◽  
Aerobic Dive Limit ◽  
Fur Seals ◽  
Lactating Females ◽  
Colony Attendance

The dive behaviour, foraging locations, and colony-attendance patterns of female Australian fur seals (Arctocephalus pusillus doriferus) from Kanowna Island (39°10'S, 146°18'E) in Bass Strait, southeastern Australia, were determined throughout lactation during 1997–1999. Foraging-trip durations increased as lactation progressed, being shortest in summer (3.71 ± 0.24 days; mean ± 1 SE) and longest in winter (6.77 ± 0.57 days, P < 0.05), but maternal-attendance periods did not differ in duration (1.70 ± 0.10 days, P > 0.5). Individual mean attendance periods and trip durations were positively correlated (r2 = 0.21, P < 0.005). Diving commenced shortly after seals left the colony (2.6 ± 0.4 h), was continuous for long periods (up to 36 h), occurred mostly during daylight hours, and lacked regular diel variation in depth. The majority of dives (78%) were typically U-shaped and reached depths corresponding to the prevailing depths in Bass Strait (65–85 m), indicating that these animals forage mostly on the benthos of the shallow continental shelf in this region. Such behaviour is unusual for fur seals but is reminiscent of that of some sea lion species. Mean dive durations varied between 2.0 and 3.7 min (maximum 8.9 min) and the theoretical aerobic dive limit (3.91–4.26 min) was exceeded on 17.3% of dives. Dive frequency (8.3 ± 0.6/h) and the proportion of time at sea spent diving (40.7 ± 2.1%) were weakly negatively related to the duration of the foraging trip (r2 = 0.07, P < 0.004, and r2 = 0.13, P < 0.0001, respectively). Data from at-sea locations showed that lactating females forage almost exclusively within Bass Strait during all seasons.

Predicting changes in distribution of a large coastal shark in the face of the strengthening East Australian Current

2020 ◽  
Vol 642 ◽  
pp. 163-177 ◽  
Author(s):  
Y Niella ◽  
AF Smoothey ◽  
V Peddemors ◽  
R Harcourt
Keyword(s):  
Austral Summer ◽  
Conservation Strategies ◽  
Limiting Factor ◽  
Commercial Fisheries ◽  
East Australian Current ◽  
Spatial And Temporal Patterns ◽  
Marine Animals ◽  
Factors Affecting ◽  
Southeastern Australia ◽  
The Face

In the face of accelerating climate change, conservation strategies will need to consider how marine animals deal with forecast environmental change as well as ongoing threats. We used 10 yr (2009-2018) of data from commercial fisheries and a bather protection program along the coast of New South Wales (NSW), southeastern Australia, to investigate (1) spatial and temporal patterns of occurrence in bull sharks and (2) environmental factors affecting bull shark occurrence along the coast of NSW. Predicted future distribution for this species was modelled for the forecast strengthening East Australian Current. Bull sharks were mostly harvested in small to larger estuaries, with average depth and rainfall responsible for contrasting patterns for each of the fisheries. There was an increase in the occurrence of bull sharks over the last decade, particularly among coastal setline fisheries, associated with seasonal availability of thermal gradients >22°C and both westward and southward coastal currents stronger than 0.15 and 0.60 m s-1, respectively, during the austral summer. Our model predicts a 3 mo increase in the availability of favourable water temperatures along the entire coast of NSW for bull sharks by 2030. This coastline provides a uniquely favourable topography for range expansion in the face of a southerly shift of warmer waters, and habitat is unlikely to be a limiting factor for bull sharks in the future. Such a southerly shift in distribution has implications for the management of bull sharks both in commercial fisheries and for mitigation of shark-human interactions.

Habitat use of cownose rays (Rhinoptera bonasus) in a highly productive, hypoxic continental shelf ecosystem

2010 ◽  
Vol 19 (4) ◽  
pp. 301-317 ◽  
Author(s):  
J. K. CRAIG ◽  
P. C. GILLIKIN ◽  
M. A. MAGELNICKI ◽  
L. N. MAY
Keyword(s):  
Habitat Use ◽  
Continental Shelf ◽  
Rhinoptera Bonasus

Satellite Tracker Deployments On Adult, Male Australian Fur Seals (Arctophalus Pusillus Doriferus): Methods And Preliminary Results

2002 ◽  
Vol 24 (1) ◽  
pp. 73 ◽  
Author(s):  
R Kirkwood ◽  
N Gales ◽  
M Lynch ◽  
P Dann
Keyword(s):  
Adult Male ◽  
Early Spring ◽  
Preliminary Results ◽  
Fur Seals ◽  
Satellite Transmitters ◽  
Rest Sites ◽  
Water Depths

In May 1999, four adult male, Australian fur seals (Arctocephalus pusillus doriferus) from the Seal Rocks colony, Victoria, were fitted with satellite transmitters that provided locations for between 2 and 7 months. Foraging trips during winter and early spring averaged 7.4 days (range for all trips 0.9 to 24.6) and between-trip rests lasted 2.8 days (range 0.3 to 5.7). Between-trip rest sites included Seal Rocks, other colonies and other haul-out sites. The seals foraged mostly in western Bass Strait and in water depths < 100 m.

scholarly journals Mass Mortality of Adult Male Subantarctic Fur Seals: Are Alien Mice the Culprits?

PLoS ONE ◽  
2008 ◽  
Vol 3 (11) ◽  
pp. e3757 ◽  
Author(s):  
P. J. Nico de Bruyn ◽  
Armanda D. S. Bastos ◽  
Candice Eadie ◽  
Cheryl A. Tosh ◽  
Marthán N. Bester
Keyword(s):  
Adult Male ◽  
Mass Mortality ◽  
Fur Seals ◽  
Subantarctic Fur Seals

Individual foraging site fidelity in lactating New Zealand fur seals: Continental shelf vs. oceanic habitats

2011 ◽  
Vol 28 (2) ◽  
pp. 276-294 ◽  
Author(s):  
Alastair M. M. Baylis ◽  
Brad Page ◽  
Jane McKenzie ◽  
Simon D. Goldsworthy
Keyword(s):  
New Zealand ◽  
Continental Shelf ◽  
Site Fidelity ◽  
Fur Seals ◽  
Foraging Site

Foraging trip strategies and habitat use during late pup rearing by lactating Australian fur seals

2011 ◽  
Vol 59 (4) ◽  
pp. 216 ◽  
Author(s):  
Roger Kirkwood ◽  
John P. Y. Arnould
Keyword(s):  
Habitat Use ◽  
Marine Mammal ◽  
Hot Spots ◽  
Marine Reserves ◽  
Central Place ◽  
Shelf Edge ◽  
Fur Seals ◽  
Eastern Australia ◽  
Management Perspective ◽  
Latitudinal Range

Australian fur seals (Arctocephalus pusillus doriferus) are the most conspicuous and abundant marine mammal in shelf waters of south-eastern Australia. To successfully rear offspring, the females must encounter sufficient prey on each foraging trip out of a central place for periods up to11 months each year. We investigated foraging trip strategies and habitat use by the females in three winter–spring periods, 2001–03, from four colonies that span the species’ latitudinal range and contribute 80% of pup production. Trip durations of 37 females averaged 6.1 ± 0.5 (s.e.) days, although >90% of the seal’s time at sea was spent <150 km travel (<2 days) away. Most females exhibited strong fidelities to individually preferred hot-spots. Females from colonies adjacent to productive shelf-edge waters generally had shorter trips, had smaller ranges, foraged closer to colonies and exhibited less diversity in trip strategies than did those from colonies more distant from a shelf-edge. From a management perspective, there was minimal overlap (<1%) between where females foraged and a system of marine reserves established in 2007, suggesting that habitats visited by lactating Australian fur seals currently receive minimal legislative protection.

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