A gross and microscopic study of the respiratory anatomy of the antarctic weddell seal,Leptonychotes weddelli

1975 ◽  
Vol 147 (3) ◽  
pp. 309-335 ◽  
Author(s):  
Robert B. Boyd
Keyword(s):  
Microscopic Study ◽  
Weddell Seal ◽  
The Antarctic

Analysis of ZP1 gene reveals differences in zona pellucida composition in carnivores

2018 ◽  
Vol 30 (2) ◽  
pp. 272 ◽  
Author(s):  
C. Moros-Nicolás ◽  
A. Leza ◽  
P. Chevret ◽  
A. Guillén-Martínez ◽  
L. González-Brusi ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
In Silico ◽  
Polar Bear ◽  
Acrosome Reaction ◽  
Stop Codon ◽  
In Silico Analysis ◽  
Weddell Seal ◽  
Fur Seal ◽  
The Antarctic ◽  
Silico Analysis

The zona pellucida (ZP) is an extracellular envelope that surrounds mammalian oocytes. This coat participates in the interaction between gametes, induction of the acrosome reaction, block of polyspermy and protection of the oviductal embryo. Previous studies suggested that carnivore ZP was formed by three glycoproteins (ZP2, ZP3 and ZP4), with ZP1 being a pseudogene. However, a recent study in the cat found that all four proteins were expressed. In the present study, in silico and molecular analyses were performed in several carnivores to clarify the ZP composition in this order of mammals. The in silico analysis demonstrated the presence of the ZP1 gene in five carnivores: cheetah, panda, polar bear, tiger and walrus, whereas in the Antarctic fur seal and the Weddell seal there was evidence of pseudogenisation. Molecular analysis showed the presence of four ZP transcripts in ferret ovaries (ZP1, ZP2, ZP3 and ZP4) and three in fox ovaries (ZP2, ZP3 and ZP4). Analysis of the fox ZP1 gene showed the presence of a stop codon. The results strongly suggest that all four ZP genes are expressed in most carnivores, whereas ZP1 pseudogenisation seems to have independently affected three families (Canidae, Otariidae and Phocidae) of the carnivore tree.

scholarly journals Social Sensors for Wildlife: Ecological Opportunities in the Era of Camera Ubiquity

2021 ◽  
Vol 8 ◽  
Author(s):  
Alex Borowicz ◽  
Heather J. Lynch ◽  
Tyler Estro ◽  
Catherine Foley ◽  
Bento Gonçalves ◽  
...  
Keyword(s):  
Ad Hoc ◽  
Individual Recognition ◽  
Image Data ◽  
Weddell Seal ◽  
Science Data ◽  
Photo Identification ◽  
Mobile Species ◽  
Community Science ◽  
The Antarctic ◽  
Social Sensors

Expansive study areas, such as those used by highly-mobile species, provide numerous logistical challenges for researchers. Community science initiatives have been proposed as a means of overcoming some of these challenges but often suffer from low uptake or limited long-term participation rates. Nevertheless, there are many places where the public has a much higher visitation rate than do field researchers. Here we demonstrate a passive means of collecting community science data by sourcing ecological image data from the digital public, who act as “eco-social sensors,” via a public photo-sharing platform—Flickr. To achieve this, we use freely-available Python packages and simple applications of convolutional neural networks. Using the Weddell seal (Leptonychotes weddellii) on the Antarctic Peninsula as an example, we use these data with field survey data to demonstrate the viability of photo-identification for this species, supplement traditional field studies to better understand patterns of habitat use, describe spatial and sex-specific signals in molt phenology, and examine behavioral differences between the Antarctic Peninsula’s Weddell seal population and better-studied populations in the species’ more southerly fast-ice habitat. While our analyses are unavoidably limited by the relatively small volume of imagery currently available, this pilot study demonstrates the utility an eco-social sensors approach, the value of ad hoc wildlife photography, the role of geographic metadata for the incorporation of such imagery into ecological analyses, the remaining challenges of computer vision for ecological applications, and the viability of pelage patterns for use in individual recognition for this species.

scholarly journals The cephalopod prey of the Weddell seal, Leptonychotes weddellii, a biological sampler of the Antarctic marine ecosystem

Polar Biology ◽  
2015 ◽  
Vol 39 (3) ◽  
pp. 561-564 ◽  
Author(s):  
A. Negri ◽  
G. A. Daneri ◽  
F. Ceia ◽  
R. Vieira ◽  
Y. Cherel ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Weddell Seal ◽  
Leptonychotes Weddellii ◽  
Antarctic Marine ◽  
The Antarctic

Chlordane residues in krill, fish and Weddell seal from the Antarctic

1986 ◽  
Vol 11 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Masahide Kawano ◽  
Tsuyoshi Inoue ◽  
Hideo Hidaka ◽  
Ryo Tatsukawa
Keyword(s):  
Weddell Seal ◽  
The Antarctic

Ecology of the ringed seal, Phoca hispida, in its fast ice breeding habitat

1981 ◽  
Vol 59 (6) ◽  
pp. 966-981 ◽  
Author(s):  
Thomas G. Smith ◽  
Michael O. Hammill
Keyword(s):  
Behavioral Ecology ◽  
Population Regulation ◽  
Weddell Seal ◽  
Breeding Habitat ◽  
Baffin Island ◽  
Phoca Hispida ◽  
Fast Ice ◽  
Site Tenacity ◽  
Males And Females ◽  
The Antarctic

Studies of the behavioral ecology of seals hauled out on the sea ice at Popham Bay (64°17′ N, 65°30′ W) southeastern Baffin Island were conducted from 8 May to 6 June 1978 and 1 May to 20 June 1979. Similar densities and seasonal changes in numbers of hauled out seals were seen in both years. Seal numbers were positively correlated with date and negatively correlated with wind speed. While lying on the ice seals were vigilant and aggressive towards other seals, and females suckled their pups. Individuals were recognized by their different pelage marks. Both males and females showed site tenacity. One male, seen in 1978, was resighted in the study area in 1979. Our observations indicate that ringed seals are territorial and similar to the polygynous Weddell seal of the antarctic in their social organization. Population regulation appears to be affected by availability of suitable fast ice in which to maintain feeding and breeding habitat, with some adjustment of annual recruitment possibly in response to depleted food resources.

Decadal-scale changes in the climate and biota of the Pacific sector of the Southern Ocean, 1950s to the 1990s

2005 ◽  
Vol 17 (2) ◽  
pp. 171-182 ◽  
Author(s):  
DAVID G. AINLEY ◽  
ELIZABETH D. CLARKE ◽  
KEVIN ARRIGO ◽  
WILLIAM R. FRASER ◽  
AKIKO KATO ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Weddell Seal ◽  
Pygoscelis Adeliae ◽  
Proximate Mechanisms ◽  
The Pacific ◽  
Decadal Scale ◽  
The Antarctic ◽  
Penguin Species

Simultaneous, but contrary, decadal-scale changes in population trajectories of two penguin species in the western Pacific and Ross Sea sectors of the Southern Ocean, during the early/mid-1970s and again during 1988–89, correspond to changes in weather and sea ice patterns. These in turn are related to shifts in the semi-annual and Antarctic oscillations. Populations of the two ecologically dissimilar penguin species - Adélie Pygoscelis adeliae and emperor Aptenodytes forsteri - have been tallied annually since the 1950s making these the longest biological datasets for the Antarctic. Both species are obligates of sea ice and, therefore, allowing for the demographic lags inherent in the response of long-lived species to habitat or environmental variation, the proximate mechanisms responsible for the shifts involved changes in coastal wind strength and air and sea temperatures, which in turn affected the seasonal formation and decay of sea ice and polynyas. The latter probably affected such rates as the proportion of adults breeding and ultimately the reproductive output of populations in ways consistent with the two species' opposing sea ice needs. Corresponding patterns for the mid-1970s shift were reflected also in ice-obligate Weddell seal Leptonychotes weddelli populations and the structure of shallow-water sponge communities in the Ross Sea. The 1988–89 shift, by which time many more datasets had become available, was reflected among several ice-frequenting vertebrate species from all Southern Ocean sectors. Therefore, the patterns most clearly identified in the Pacific Sector were apparently spread throughout the high latitudes of the Southern Ocean.

Population aspects of Weddell Seal harvesting at McMurdo Sound, Antarctica

Polar Record ◽  
1971 ◽  
Vol 15 (98) ◽  
pp. 653-667 ◽  
Author(s):  
Ian Stirling
Keyword(s):  
Weddell Seal ◽  
Alternative Food ◽  
Biological Research ◽  
Mcmurdo Sound ◽  
Annual Crop ◽  
Weddell Seals ◽  
Antarctic Treaty ◽  
The Antarctic

The preservation and conservation of living resources was one of the original stated objectives of the Antarctic Treaty, 1959. The harvesting of animals near bases for food, especially Weddell Seals Leptonychotes weddelli received particular attention at the Fourth Meeting of SCAR, 1960 (Polar Record,1961) and several regulations were suggested including: a permit required before killing, records to be kept of animals killed, and use of alternative food where possible. Annex D, Section (b)i states “… Without detailed biological research it is impossible to assess the permissible annual crop which the various [Weddell] seal colonies would stand, but it is certain that this figure is being seriously exceeded in many areas.”

Helminths from the Weddell seal, Leptonychotes weddelli (Lesson, 1826), in the Antarctic

1971 ◽  
Vol 49 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Mary Beverley-Burton
Keyword(s):  
Numerical Data ◽  
Weddell Seal ◽  
Helminth Parasites ◽  
Intensity Of Infection ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
The Antarctic

The alimentary tracts of seven Weddell seals taken at McMurdo Sound, Antarctica, were examined for helminth parasites. Two species of trematodes, three of cestodes, and one of nematodes were recovered. Numerical data on incidence and intensity of infection are given for each species. Heavy infections of diphyllobothriid plerocercoids were also recorded.

Short Note: The Antarctic toothfish: how common a prey for Weddell seals?

2007 ◽  
Vol 19 (4) ◽  
pp. 441-442 ◽  
Author(s):  
P.J. Ponganis ◽  
T.K. Stockard
Keyword(s):  
Short Note ◽  
Weddell Seal ◽  
Large Prey ◽  
Pleuragramma Antarcticum ◽  
Antarctic Toothfish ◽  
Weddell Seals ◽  
Dissostichus Mawsoni ◽  
Antarctic Silverfish ◽  
The Antarctic ◽  
Ice Fish

The Antarctic toothfish (Dissostichus mawsoni Norman) has been considered an occasional large prey item of the Weddell seal (Leptonychotes weddellii Lesson) (Kooyman 1967, Calhaem & Christoffel 1969, Testa et al. 1985, Castellini et al. 1992, Davis et al. 1999, Fuiman et al. 2002). The seal's most common prey is the Antarctic silverfish (Pleuragramma antarcticum Boulenger) as well as benthic and sub-ice fish, cephalopods, and crustaceans (Dearborn 1965, Green & Burton 1987, Plotz 1987, Plotz et al. 1991, Castellini et al. 1992, Burns et al. 1998).

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