Difficulties in assessing population status of ice seals

1995 ◽  
Vol 22 (2) ◽  
pp. 193 ◽  
Author(s):  
RA McFarlane ◽  
AA Flaherty ◽  
BC Pahl ◽  
SA Haigh
Keyword(s):  
Prey Species ◽  
Weddell Seal ◽  
Population Status ◽  
Reproductive Condition ◽  
Elephant Seals ◽  
Weddell Seals ◽  
Southern Elephant Seals ◽  
Fast Ice ◽  
Crabeater Seals

The best method of monitoring ice seal populations in shifting packice is by aerial censuses. However, there are a number of problems with this method that are difficult to address in the packice and are best addressed on more accessible ice seals such as the Weddell seal. Counts made during the moult are affected by the fact that Weddell seals can leave the fast ice to forage. Seal numbers on the fast ice will therefore differ depending upon the proximity and availability of prey species, with lower numbers being recorded on the fast ice the further the seal has to travel from the ice to find food. In any census the subgroup of the population that is being counted must be known. Southern elephant seals and Weddell seals haul out to moult in sequences on the basis of age, sex and reproductive condition. This leads to periods of high and low counts through the moult. Examination of data on crabeater seals indicates that a putative 60% decline in numbers may have been due to counts being made at different times of the moult and therefore with different subgroups of the population being counted.

Distinct gut microbiotas between southern elephant seals and Weddell seals of Antarctica

2020 ◽  
Vol 58 (12) ◽  
pp. 1018-1026
Author(s):  
Mincheol Kim ◽  
Hyunjun Cho ◽  
Won Young Lee
Keyword(s):  
Elephant Seals ◽  
Weddell Seals ◽  
Southern Elephant Seals

The behavioural response of lactating Weddell seals (Leptonychotes weddellii) to over-snow vehicles: a case study

2007 ◽  
Vol 85 (4) ◽  
pp. 488-496 ◽  
Author(s):  
T.D. van Polanen Petel ◽  
M.A. Giese ◽  
S. Wotherspoon ◽  
M.A. Hindell
Keyword(s):  
Adult Female ◽  
Scientific Research ◽  
Weddell Seal ◽  
Behavioural Response ◽  
Leptonychotes Weddellii ◽  
Weddell Seals ◽  
Fast Ice ◽  
Vehicle Activity

Over-snow vehicles are used extensively at Antarctic scientific research stations. Adult female Weddell seals ( Leptonychotes weddellii (Lesson, 1826)) also utilise the fast-ice and are therefore often exposed to vehicular activity, with the potential of affecting their behaviour. Guidelines for vehicular travel have been developed to minimise disturbance to Antarctic wildlife; however, these guidelines have not yet been scientifically tested. To examine the efficiency and sensitivity of existing guidelines used within the Australian Antarctic Territory (AAT), we conducted drive-by experiments of two types of over-snow vehicles. The results of these experiments showed that the probability of a lactating Weddell seal looking at the vehicles and the duration of the seals’ looking at the vehicles were dependent on the distance between vehicles and seals, the position of the pups in relation to its mother, and the distance the adult female was from the water. Although the seals apparently perceived the vehicles to be a threat, no seals fled in response to vehicle activity. We propose that the existing guidelines used in the AAT could be amended to increase separation distances between vehicles and breeding Weddell seals if the goal of management is to ensure that Weddell seal behaviour is unaffected by vehicle travel.

scholarly journals Weddell seal observations on female and pup behavior and breeding status for four overwintering periods (2015 to 2018) at Barton Peninsula, King George Island, Antarctica

2020 ◽  
Vol 10 (1) ◽  
pp. 1-6
Author(s):  
Yejin Kim ◽  
In-Young Ahn ◽  
Ji Kang Park ◽  
Won Young Lee
Keyword(s):  
Weddell Seal ◽  
Breeding Cycle ◽  
King George Island ◽  
Weddell Seals ◽  
Barton Peninsula ◽  
Fast Ice ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Breeding Status

In animal ecology studies, it is a fundamental monitoring work to observe annual breeding cycle. In this study, we report the detailed observations on seven mother and pup pairs of Weddell seal (Leptonychotes weddellii) at Barton peninsula, King George Island, Antarctica. Two or three pairs had been observed along the coast on the fast ice in 2015, 2017, and 2018 and no breeding was recorded in 2016. Although it varied among individuals, pups were recorded to be born on 19−25 Sept., began swimming at day 18−19 after birth, and molted at day 21−25. Our observations may provide fundamental breeding information of Weddell seals in our study site and contribute to the future long-term monitoring research of seals.

Records of vagrant phocid seals (family Phocidae) in South Australia

2012 ◽  
Vol 34 (2) ◽  
pp. 155 ◽  
Author(s):  
Peter D. Shaughnessy ◽  
Catherine M. Kemper ◽  
John K. Ling
Keyword(s):  
South Australia ◽  
Breeding Site ◽  
Weddell Seal ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
Elephant Seals ◽  
Macquarie Island ◽  
The Public ◽  
Phocid Seals ◽  
Crabeater Seals

Five species of phocid seal of the Southern Ocean and Antarctica come ashore occasionally on the southern Australian coast but do not breed there. We document records (specimens and sightings) of visits to South Australia (SA) by southern phocids from 1883 until August 2011. We used records from the SA Museum, reports from coastal officers of SA Department of Environment and Natural Resources (DENR), the DENR fauna database, information from the public, the literature and newspapers. Thirty-six southern elephant seal records included two births, in November 1932 and October 1986. The latter pup suckled for 20 days and then stayed ashore for eight weeks; both are similar to average durations at Macquarie Island. Of 33 dated records, 31 were between August and April, when elephant seals at Macquarie Island (the closest breeding site) are ashore to breed or moult. A recognisable male on Kangaroo Island has been sighted often over 10 years to 2010. Of the ice-breeding species, there were 54 leopard seal records. All of 40 dated records were between June and December, with the maximum (12) in August, similar to the seasonal distribution in Tasmania. There were five records of crabeater seals, one of a Ross seal, and one of a Weddell seal.

Age-specific survival, abundance, and immigration rates of a Weddell seal (Leptonychotes weddellii) population in McMurdo Sound, Antarctica

2004 ◽  
Vol 82 (4) ◽  
pp. 601-615 ◽  
Author(s):  
Michael F Cameron ◽  
Donald B Siniff
Keyword(s):  
Information Criterion ◽  
Weddell Seal ◽  
Adult Survival ◽  
Sea Ice Extent ◽  
Leptonychotes Weddellii ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
Abundance Estimates ◽  
Fast Ice ◽  
The 1960S

Since the 1960s, Weddell seals (Leptonychotes weddellii (Lesson, 1826)) have been tagged and surveyed annually in McMurdo Sound, Antarctica. Mark–recapture analyses and model selection trials using Akaike's Information Criterion indicate that sex, cohort, and year affect juvenile (ages 1 and 2) survival. In contrast, year and perhaps sex and cohort are less important factors for adult survival. Average annual survival is higher among adults (0.93) than juveniles (0.55–0.59) and there is little evidence for senescence to at least age 17. The oldest known-aged female and male in the study were 27 and 24 years old, respectively. Data suggest that the abundance of a resident population of Weddell seals remains relatively stable over time despite annual fluctuations in Jolly–Seber abundance estimates for the entire population. We argue that this annual variability is likely the result of temporary immigration of animals born outside the study area; mean rates are estimated from a simulation model and tagging data to be between 16.8% and 39.7% for females and between –13.1% and 31.6% for males. Sea ice extent appears to affect immigration where, during times of reduced fast-ice, immigrants are forced, or allowed easier access, into the ice-covered areas of Erebus Bay from surrounding locations. Our findings contradict previous studies reporting lower survival and higher immigration. Model choice is shown to be the most likely cause of these discrepancies and we provide evidence that our models are more appropriate than those used elsewhere.

Antarctic pack ice seal observations during spring across the Lazarev Sea

Polar Record ◽  
2021 ◽  
Vol 57 ◽  
Author(s):  
Marthán N. Bester ◽  
Nico Lübcker ◽  
Wiam Haddad ◽  
Horst Bornemann ◽  
Mia Wege
Keyword(s):  
Distribution Density ◽  
Austral Spring ◽  
Weddell Seals ◽  
Fur Seals ◽  
Marginal Sea ◽  
Pack Ice ◽  
Fast Ice ◽  
Crabeater Seals ◽  
Early Late ◽  
Track Line

Abstract The distribution, density and percentage contribution of pack ice seals during ship-board censuses in the marginal sea ice zone beyond the Lazarev Sea in spring 2019 are presented. Adult/juvenile crabeater seals (n = 19), leopard seals (n = 3) and Ross seals (n = 10) were sighted during 582.2 nm of censuses along the ship’s track line in the area bounded by 00°00’–22°E and 56°–60°S. Antarctic fur seals (n = 21) were only encountered on the outer fringes of the pack ice, and Weddell seals were absent due to their primary use of fast ice and inner pack ice habitats close to the coast. Crabeater seal sightings included juveniles (n = 2) and another four groups of 2–3 unclassified crabeater seals, singletons (n = 5), single mothers with pups (n = 3) and a family group (n = 1 triad). Only one leopard seal attended a pup, while no Ross seal pups were located. The survey was likely of insufficient effort, in both extent (north of 60°S) and duration (18 days), to locate seals in considerable numbers this early (late October/early November) in their austral spring breeding season.

Serological screening for Brucella spp. and Leptospira spp. antibodies in southern elephant seals Mirounga leonina from Elephant Island, Antarctica, in 2003 and 2004

2020 ◽  
Vol 142 ◽  
pp. 161-170
Author(s):  
AM Sánchez-Sarmiento ◽  
V Ruoppolo ◽  
MMC Muelbert ◽  
JS Ferreira Neto ◽  
JL Catão-Dias
Keyword(s):  
Austral Summer ◽  
Agglutination Test ◽  
South Shetland Islands ◽  
Climate Change Scenarios ◽  
Mirounga Leonina ◽  
Serological Screening ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
Monitoring And Surveillance ◽  
Elephant Island

Brucella spp. and Leptospira spp. antibodies were surveyed in 35 southern elephant seals (SESs) Mirounga leonina at Elephant Island (South Shetland Islands), western Antarctic peninsula, in the Austral summer of 2003 and 2004. The rose Bengal test and a commercial competitive ELISA (c-ELISA) were used to detect Brucella spp. exposure, and the microscopic agglutination test (MAT) with 22 live serovars was used to determine anti-Leptospira spp. antibodies. We found evidence of Brucella spp. exposure in 3 of 35 (8.6%) SESs tested via the c-ELISA displaying high percentage inhibition (PI), similar to other studies in pinnipeds in which Brucella spp. antibodies have been determined. Two of the 3 positives were pups (PI = 70.4 and 86.6%), while the third was an adult female (PI = 48.8%). The 3 c-ELISA positive SESs were additionally tested via the serum agglutination test but were found to be negative. All individuals were negative for antibodies against 22 Leptospira spp. serovars by MAT. These results contribute to the knowledge and monitoring of zoonotic pathogens with epizootic potential in Southern Ocean pinnipeds. Given the potential impact that pathogens may have on the abundance of wild (sometimes threatened and endangered) populations, constant monitoring and surveillance are required to prevent pathogen spread, particularly under forecast climate change scenarios.

Animal-Borne Instrumentation Systems and the Animals that Bear Them: Then (1939) and Now (2007)

2007 ◽  
Vol 41 (4) ◽  
pp. 6-8 ◽  
Author(s):  
Gerald Kooyman
Keyword(s):  
Loggerhead Turtle ◽  
Video Camera ◽  
Weddell Seal ◽  
Gps Tracking ◽  
Major Step ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
History Of ◽  
Archival Systems ◽  
Microprocessor Technology

The history of animal-borne instrumentation is reviewed from the first basic depth gauge invented in the late 1800s, to the complex animal-borne imagery and archival systems of the present day. A major breakthrough occurred in 1964 when the first time-depth recorder was deployed on a Weddell Seal in McMurdo Sound, Antarctica. The next phase in the study of animals at sea was the use of microprocessors as archival recorders in the mid-1980s. These also were first attached to Weddell seals in McMurdo Sound. Microprocessor technology made possible the next major step of attaching a video camera housed in a submersible case (Crittercam) to a loggerhead turtle. Since the 1990s the field of “Biologging” has flourished, with new additions of satellite and GPS tracking, and resulted in three major international symposiums in the past four years (2003-2007).

Movements of southern elephant seals

1996 ◽  
Vol 74 (8) ◽  
pp. 1485-1496 ◽  
Author(s):  
B. J. McConnell ◽  
M. A. Fedak
Keyword(s):  
Southern Ocean ◽  
Continental Shelf ◽  
Antarctic Peninsula ◽  
Average Rate ◽  
Stationary Phases ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
South Georgia ◽  
Southern Elephant Seals ◽  
The Antarctic

Twelve southern elephant seals (Mirounga leonina) were tracked for an average of 119 days as they left their breeding or moulting beaches on the island of South Georgia between 1990 and 1994. Females travelled either eastward up to 3000 km away to the open Southern Ocean or to the continental shelf on or near the Antarctic Peninsula. Males either stayed close to South Georgia or used South Georgia as a base for shorter trips. The females all left South Georgia in a directed manner at an average rate of 79.4 km/day over at least the first 15 days. Thereafter travel was interrupted by bouts of slower travel or stationary phases. The latter were localized at sites on the continental shelf or along its edge. Three seals that were tracked over more than one season repeated their outward direction of travel and used some of the same sites in subsequent years. The magnitude of the movements makes most of the Southern Ocean potentially available to elephant seals.

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