Habitat use and diving behaviour of male Australian fur seals

2017 ◽  
Vol 566 ◽  
pp. 243-256 ◽  
Author(s):  
TC Knox ◽  
AMM Baylis ◽  
JPY Arnould
Keyword(s):  
Habitat Use ◽  
Diving Behaviour ◽  
Fur Seals

Geographic variation in at-sea movements, habitat use and diving behaviour of female Cape fur seals

2020 ◽  
Vol 649 ◽  
pp. 201-218
Author(s):  
JA Botha ◽  
SP Kirkman ◽  
JPY Arnould ◽  
AT Lombard ◽  
GJG Hofmeyr ◽  
...  
Keyword(s):  
Habitat Use ◽  
Prey Species ◽  
Dive Depth ◽  
Diving Behaviour ◽  
Foraging Strategies ◽  
Suitable Habitat ◽  
Vertical Movements ◽  
Marine Predator ◽  
Fur Seals ◽  
Shelf Slope

Knowledge of animal foraging behaviour has implications for management and conservation. While Cape fur seals Arctocephalus pusillus pusillus comprise a major proportion of the southern African marine predator biomass, little is known about their at-sea movements. We investigated foraging distribution, habitat use and diving behaviour for 35 adult female Cape fur seals from 3 breeding colonies experiencing contrasting oceanographic regimes. Animals from Black Rocks, the smallest and eastern-most colony, undertook shorter foraging trips and utilised shallower waters over the shelf. In comparison, animals from the larger west coast colonies, at Kleinsee and False Bay, travelled further and utilised deeper shelf and shelf-slope waters. However, across colonies, females typically preferred depths of <500 m and slopes of <5°. Kleinsee and False Bay seals selected sea surface temperatures within the range typically preferred by pelagic prey species such as round herring, sardine and anchovy (14-19°C). Black Rocks individuals showed bimodal preferences for colder (16°C) and warmer waters (>22°C). Dive behaviour was similar between Kleinsee and False Bay individuals (unavailable from Black Rocks), with both pelagic and benthic foraging evident. Diel patterns were apparent at both sites, as dive depth and benthic diving increased significantly during daylight hours, likely reflecting vertical movements of prey species. We provide the first assessment of Cape fur seal movement behaviour for the South African component of the population. Observed geographic differences likely reflect the availability of suitable habitat but may also indicate differences in foraging strategies and density-dependent effects throughout the range of this species.

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.

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.

scholarly journals Habitat use and diving behaviour of gravid olive ridley sea turtles under riverine conditions in French Guiana

2017 ◽  
Vol 165 ◽  
pp. 115-123 ◽  
Author(s):  
Philippine Chambault ◽  
Lucie Giraudou ◽  
Benoît de Thoisy ◽  
Marc Bonola ◽  
Laurent Kelle ◽  
...  
Keyword(s):  
Habitat Use ◽  
French Guiana ◽  
Sea Turtles ◽  
Diving Behaviour ◽  
Olive Ridley ◽  
Olive Ridley Sea Turtles

scholarly journals Changes in diving behaviour and habitat use of provisioned whale sharks: implications for management

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gonzalo Araujo ◽  
Jessica Labaja ◽  
Sally Snow ◽  
Charlie Huveneers ◽  
Alessandro Ponzo
Keyword(s):  
Endangered Species ◽  
Habitat Use ◽  
Metabolic Rate ◽  
Sustainable Tourism ◽  
Diving Behaviour ◽  
Whale Shark ◽  
Rhincodon Typus ◽  
The World ◽  
Whale Sharks ◽  
Temperature Depth

Abstract Whale shark (Rhincodon typus) tourism is increasingly popular at predictable aggregations around the world, but only a few use provisioning to ensure close interactions. Understanding the effects of provisioning on the behaviour of this endangered species is critical to manage this growing industry. We recorded the diving behaviour and habitat use of juvenile whale sharks (n = 4) for a mean of 49.5 provisioned and 33.8 non-provisioned days using temperature-depth-recorders. We found that time spent at the surface (< 2 m) between 6 am and 1 pm increased ~ sixfold, while timing of deep dives shifted from 4–10 am to 10 am–2 pm, i.e. near or at the end of the provisioning activities. The shift might be related to a need to thermoregulate following a prolonged period of time in warmer water. These changes could have fitness implications for individuals frequently visiting the provisioning site. Based on recorded amount of time spent in warm waters and published Q10 values for ectotherms, we estimate a 7.2 ± 3.7% (range 1.3–17.8%) higher metabolic rate when sharks frequent the provisioning site. The observed behavioural, habitat use, and potential fitness shifts should be considered when developing guidelines for sustainable tourism, particularly in light of new provisioning sites developing elsewhere.

scholarly journals Factors affecting energy expenditure in a declining fur seal population

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Elizabeth A McHuron ◽  
Jeremy T Sterling ◽  
Daniel P Costa ◽  
Michael E Goebel
Keyword(s):  
Environmental Changes ◽  
Food Limitation ◽  
Population Decline ◽  
Indirect Evidence ◽  
Diving Behaviour ◽  
Trip Duration ◽  
Metabolic Rates ◽  
Fur Seals ◽  
Northern Fur Seals ◽  
Pribilof Islands

Abstract Quantifying metabolic rates and the factors that influence them is key to wildlife conservation efforts because anthropogenic activities and habitat alteration can disrupt energy balance, which is critical for reproduction and survival. We investigated the effect of diving behaviour, diet and season on field metabolic rates (FMR) and foraging success of lactating northern fur seals (Callorhinus ursinus) from the Pribilof Islands during a period of population decline. Variation in at-sea FMR was in part explained by season and trip duration, with values that ranged from 5.18 to 9.68 W kg−1 (n = 48). Fur seals experienced a 7.2% increase in at-sea FMR from summer to fall and a 1.9% decrease in at-sea FMR for each additional day spent at sea. There was no effect of foraging effort, dive depth or diet on at-sea FMR. Mass gains increased with trip duration and were greater in the fall compared with summer, but were unrelated to at-sea FMR, diving behaviour and diet. Seasonal increases in at-sea FMR may have been due to costs associated with the annual molt but did not appear to adversely impact the ability of females to gain mass on foraging trips. The overall high metabolic rates in conjunction with the lack of any diet-related effects on at-sea FMR suggests that northern fur seals may have reached a metabolic ceiling early in the population decline. This provides indirect evidence that food limitation may be contributing to the low pup growth rates observed in the Pribilof Islands, as a high metabolic overhead likely results in less available energy for lactation. The limited ability of female fur seals to cope with changes in prey availability through physiological mechanisms is particularly concerning given the recent and unprecedented environmental changes in the Bering Sea that are predicted to have ecosystem-level impacts.

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