Cephalopod diet of the southern elephant seal, Mirounga leonina, at King George Island, South Shetland Islands

2000 ◽  
Vol 12 (1) ◽  
pp. 16-19 ◽  
Author(s):  
G.A. Daneri ◽  
A.R. Carlini ◽  
P.G.K. Rodhouse

In the summer of 1995/96, 25 southern elephant seals, Mirounga leonina, were stomach lavaged at Stranger Point, King George Island, South Shetland Islands. Cephalopod remains were present in 72% of the individuals sampled (n = 18). Seven species of squid and three of octopus were identified. The squid Psychroteuthis glacialis was the most important prey in terms of numbers (77%), biomass (80.8%) and frequency of occurrence (94.4%). Next in importance in terms of mass was the squid Alluroteuthis antarcticus (7.8%) in the diet of females and the octopodid Pareledone ?charcoti in the diet of males (13.2%). Females preyed on a wider variety of squid taxa than males (7 vs 3) but octopodids occurred only in stomach contents from males. The predominance of P. glacialis in the prey of the South Shetland Islands elephant seals can be explained by the southerly location of the foraging areas of this population compared to South Georgia, Heard and Macquarie islands, where the diet of southern elephant seals has previously been analysed. Psychroteuthis glacialis is the predominant squid in waters close to the Antarctic continent.

2020 ◽  
Vol 12 (18) ◽  
pp. 2964
Author(s):  
Katarzyna Fudala ◽  
Robert Józef Bialik

During the 2019 breeding season (October-December), a battery-powered DIJ Inspire 2 drone was used to investigate a breeding southern elephant seal colony located at Patelnia Point (ASPA 128, King George Island, South Shetland Islands, maritime Antarctica). Twelve unmanned aerial vehicle (UAV) missions conducted 50–70 m above ground level (AGL) were completed to monitor the breeding ground with a maximum of 0.348 km2. The missions were planned in Pix4D Capture software. A drone, with the support of ground cameras and observations, was used to derive population counts, map harems, and track the phenology of the southern elephant seals. Based on data obtained from the UAV missions, orthophotomaps were created in PIX4D Mapper and then analyzed in QGIS. Calculated values of body size parameters such as body length and orthogonal body surface area were used to determine the age and sex of individuals. Analysis of the ranges of the harems on particular days, supported by an analysis of land conditions that generate physical barriers to the movement of animals, allowed zones in which the transformations of groups of harems took place to be determined. The hypothesized hermeticity of the designated zones was supported by statistical tests. The use of drones allows for comprehensive population analyses of the breeding colonies of elephant seals such as censuses of pups and adult individuals, determination of the sex ratio, and spatial analysis of the distribution of breeding formations. In addition, it allows for a more accurate result than ground counting.


Polar Biology ◽  
2014 ◽  
Vol 38 (5) ◽  
pp. 665-676 ◽  
Author(s):  
G. A. Daneri ◽  
A. R. Carlini ◽  
E. R. Marschoff ◽  
A. Harrington ◽  
J. Negrete ◽  
...  

1995 ◽  
Vol 73 (8) ◽  
pp. 1519-1528 ◽  
Author(s):  
David J. Slip

Stomach contents were lavaged from 76 southern elephant seals (Mirounga leonina) at Heard Island between July 1992 and March 1993. Eighty-six percent of stomachs contained cephalopods of 17 species. Numerically the most important was Psychroteuthis glacialis (21.1%), and from estimated biomass the most important was Kondakovia longimana (40.4%). Three other species were also common prey: Moroteuthis knipovitchi (19.4% by estimated biomass), Moroteuthis ingens (13.0%), and Alluroteuthis antarcticus (10.2%). Sixty-six percent of stomachs contained fish remains, and four species, Dissostichus eleginoides, Electrona carlsbergi, E. antarctica, and Gymnoscopelus nicholsi, were identified from otoliths. The diet of adults differed from that of juveniles, particularly pups in their first year. Martialia hyadesi was the most important prey of juveniles and represented 57.1% of estimated biomass consumed. Furthermore, smaller seals ate smaller squid. The species and size of cephalopods eaten by southern elephant seals are similar to those of other Southern Ocean predators, particularly some beaked whales.


1992 ◽  
Vol 70 (2) ◽  
pp. 370-379 ◽  
Author(s):  
Mark A. Hindell ◽  
David J. Slip ◽  
Harry R. Burton ◽  
Michael M. Bryden

The diving behaviour of 14 adult southern elephant seals was investigated using time depth recorders. Each of the seals performed some dives that were longer than its theoretical aerobic dive limit. Forty-four percent of all dives made by post-moult females exceeded the calculated limit compared with 7% of those made by postbreeding females and less than 1% of those made by adult males. The extended dives displayed characteristics that suggested that they were predominantly foraging dives, although some were apparently rest dives. Dives longer than the calculated aerobic limits often occurred in bouts; the longest consisted of 63 consecutive dives and lasted 2 days. Postmoult females performed longer bouts of extended dives than postbreeding females. Extended surface periods (longer than 30 min) were not related to the occurrence of extended dives or bouts of extended dives. The possible physiological mechanisms that permit such prolonged continuous dives are discussed. Southern elephant seals may increase the aerobic capacity of dives by lowering their metabolism to approximately 40% of the resting metabolic rate on long dives. There is substantial interseal variability in the methods used to cope with long dives. Some animals appear to use physiological strategies that allow them to prolong the time available to them at the bottom of a dive, while others use alternative strategies that may limit the time available at the bottom of their dives.


Polar Biology ◽  
2004 ◽  
Vol 27 (5) ◽  
pp. 266-276 ◽  
Author(s):  
A. R. Carlini ◽  
M. E. I. M�rquez ◽  
H. Panarello ◽  
S. Ramdohr ◽  
G. A. Daneri ◽  
...  

2000 ◽  
Vol 12 (1) ◽  
pp. 3-15 ◽  
Author(s):  
H. Bornemann ◽  
M. Kreyscher ◽  
S. Ramdohr ◽  
T. Martin ◽  
A. Carlini ◽  
...  

Weaned pups and post-moult female elephant seals (Mirounga leonina) were fitted with satellite transmitters at King George Island (South Shetland Islands) between December 1996 and February 1997. Of the nine adult females tracked for more than two months, three stayed in a localized area between the South Shetland Islands and the South Orkney Islands. The other six females travelled south-west along the coast of the Antarctic Peninsula up to the Bellingshausen Sea. Two of them then moved north-east and hauled out on South Georgia in October. One female was last located north of the South Shetland Islands in March 1998. In total, eight females were again sighted on King George Island and six of the transmitters removed. The tracks of the weaners contrasted with those of the adults. In January, five juveniles left King George Island for the Pacific sector spending about four weeks in the open sea west of the De Gerlache Seamounts. Three of them returned to the tip of the Antarctic Peninsula in June, of which one was last located on the Patagonian Shelf in November 1997. The juveniles avoided sea ice while the adults did not. The latter displayed behavioural differences in using the pack ice habitat during winter. Some females adjusted their movement patterns to the pulsating sea ice fringe in distant foraging areas while others ranged in closed pack ice of up to 100%. The feeding grounds of adult female elephant seals are more closely associated with the pack ice zone than previously assumed. The significance of the midwater fish Pleuragramma antarcticum as a potential food resource is discussed.


2018 ◽  
Author(s):  
I. D. Jonsen ◽  
C. R. McMahon ◽  
T. A. Patterson ◽  
M. Auger-Méthé ◽  
R. Harcourt ◽  
...  

AbstractLike many species, movement patterns of southern elephant seals (Mirounga leonina) are being influenced by long-term environmental change. These seals migrate up to 4000 km from their breeding colonies, foraging for months in a variety of Southern Ocean habitats. Understanding how movement patterns vary with environmental features and how these relationships differ among individuals employing different foraging strategies can provide insight into foraging performance at a population level. We apply new fast-estimation tools to fit mixed effects within a random walk movement model, rapidly inferring among-individual variability in southern elephant seal environment-movement relationships. We found that seals making foraging trips to the sea-ice on or near the Antarctic continental shelf consistently reduced speed and directionality (move persistence) with increasing sea ice coverage and had variable responses to chlorophyll a concentration, whereas seals that foraged pelagically reduced move persistence in regions where circumpolar deep water shoaled. Given future climate scenarios, pelagic foragers may encounter more productive habitat but sea-ice foragers may see reduced habitat availability. Our approach is scalable to large telemetry data sets and allows flexible combinations of mixed effects to be evaluated via model selection, thereby illuminating the ecological context of animal movements that underlie habitat use.


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