Proportional underwater call type usage by Weddell seals (Leptonychotes weddellii) in breeding and nonbreeding situations

2012 ◽  
Vol 90 (2) ◽  
pp. 237-247 ◽  
Author(s):  
Elyse E. Doiron ◽  
Philippe A. Rouget ◽  
John M. Terhune
Keyword(s):  
Sea Ice ◽  
Breeding Season ◽  
Ice Formation ◽  
Leptonychotes Weddellii ◽  
Mating Period ◽  
Call Type ◽  
Weddell Seals ◽  
Breeding Behaviour ◽  
Dark Conditions

Proportional underwater call type usage by Weddell seals ( Leptonychotes weddellii (Lesson, 1826)) near Mawson, Antarctica, investigated the hypothesis that certain call types function specifically in breeding behaviour. Recordings were collected at various sites in 2000 and 2002 from June to December. Twenty-four hour recordings were collected in 2002 at two sites. One hundred consecutive calls from each of 248 recordings were classified into one of ten common call types. Time to 100 calls provided the calling rate. The study period was divided into four periods representing initial sea-ice formation, pre-pupping, pupping, and mating. Calling rate and light–dark differences were also examined. No presence–absence differences were observed for any of the call types with season. The largest difference between nonbreeding and breeding situations was an increase from 32.2% to 38.1% for descending whistles (F[3,244] = 4.483, p = 0.004). Trills gradually increased from 1.8% to 7.3% toward the mating period (F[3,244] = 30.932, p < 0.001). The proportion of trills, chugs, descending whistles, and other call types also varied with calling rate and light–dark conditions. Some pre-reproductive behaviours may occur in winter, but no call types of Weddell seals function solely in the breeding season.

The Weddell seals of Larsen Harbour, South Georgia: a unique but apparently declining colony

Polar Record ◽  
2015 ◽  
Vol 51 (6) ◽  
pp. 667-671 ◽  
Author(s):  
Robert Burton
Keyword(s):  
Sea Ice ◽  
Breeding Season ◽  
Small Population ◽  
Single Observation ◽  
South Georgia ◽  
Weddell Seals ◽  
Cruise Ships

ABSTRACTThe small population of Weddell seals at Larsen Harbour, South Georgia, is isolated from the rest of the species and is unique because nearly all pups are born on land rather than on sea-ice. Observations of seals in Larsen Harbour during the breeding season are summarised. These have been infrequent until cruise ships started to visit. With often only a single observation in a year, accurate estimates of pup production are impossible but it appears that the population has decreased over the last three decades.

Proportional Weekly Use of Underwater Call Types by Weddell Seals, Leptonychotes Weddellii (Pinnipedia: Phocidae), During the Breeding Season at the Vestfold Hills

1996 ◽  
Vol 44 (1) ◽  
pp. 75 ◽  
Author(s):  
BC Pahl ◽  
JM Terhune ◽  
HR Burton
Keyword(s):  
Breeding Season ◽  
Leptonychotes Weddellii ◽  
Weddell Seals ◽  
Behavioural Patterns ◽  
Vestfold Hills

Underwater vocalisations by Weddell seals, Leptonychotes weddellii, were recorded during the 1992 breeding season, at the Vestfold Hills, Antarctica. Only 3 of the 12 major call types recorded at all sites had statistically significant variations in utilisation throughout the season. No consistent trends were evident. The underwater calls of Weddell seals increased;in number during the breeding season, hut the proportional weekly usage of each of the major call types did not change. The absence of vocalisation changes suggests that the breeding behaviours of Weddell seals are not synchronous and that the underwater behavioural patterns either do not change during the breeding season or could not be detected because of the asynchrony.

Seasonal variations in the properties and structural composition of sea ice and snow cover in the Bellingshausen and Amundsen Seas, Antarctica

1997 ◽  
Vol 43 (143) ◽  
pp. 138-151 ◽  
Author(s):  
M. O. Jeffries ◽  
K. Morris ◽  
W.F. Weeks ◽  
A. P. Worby
Keyword(s):  
Sea Ice ◽  
Isotopic Composition ◽  
Snow Cover ◽  
Sea Water ◽  
Ice Cores ◽  
Ice Cover ◽  
Snow Accumulation ◽  
Ice Formation ◽  
Frazil Ice ◽  
Core Sets

AbstractSixty-three ice cores were collected in the Bellingshausen and Amundsen Seas in August and September 1993 during a cruise of the R.V. Nathaniel B. Palmer. The structure and stable-isotopic composition (18O/16O) of the cores were investigated in order to understand the growth conditions and to identify the key growth processes, particularly the contribution of snow to sea-ice formation. The structure and isotopic composition of a set of 12 cores that was collected for the same purpose in the Bellingshausen Sea in March 1992 are reassessed. Frazil ice and congelation ice contribute 44% and 26%, respectively, to the composition of both the winter and summer ice-core sets, evidence that the relatively calm conditions that favour congelation-ice formation are neither as common nor as prolonged as the more turbulent conditions that favour frazil-ice growth and pancake-ice formation. Both frazil- and congelation-ice layers have an av erage thickness of 0.12 m in winter, evidence that congelation ice and pancake ice thicken primarily by dynamic processes. The thermodynamic development of the ice cover relies heavily on the formation of snow ice at the surface of floes after sea water has flooded the snow cover. Snow-ice layers have a mean thickness of 0.20 and 0.28 m in the winter and summer cores, respectively, and the contribution of snow ice to the winter (24%) and summer (16%) core sets exceeds most quantities that have been reported previously in other Antarctic pack-ice zones. The thickness and quantity of snow ice may be due to a combination of high snow-accumulation rates and snow loads, environmental conditions that favour a warm ice cover in which brine convection between the bottom and top of the ice introduces sea water to the snow/ice interface, and bottom melting losses being compensated by snow-ice formation. Layers of superimposed ice at the top of each of the summer cores make up 4.6% of the ice that was examined and they increase by a factor of 3 the quantity of snow entrained in the ice. The accumulation of superimposed ice is evidence that melting in the snow cover on Antarctic sea-ice floes ran reach an advanced stage and contribute a significant amount of snow to the total ice mass.

scholarly journals First record of the occurrence of sea ice in the Cordillera Darwin fjords (54°S), Chile

2021 ◽  
pp. 1-11
Author(s):  
Charles Salame ◽  
Inti Gonzalez ◽  
Rodrigo Gomez-Fell ◽  
Ricardo Jaña ◽  
Jorge Arigony-Neto
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
First Record ◽  
Ice Formation ◽  
Future Research ◽  
Landsat 8 ◽  
Surface Salinity ◽  
Air Temperatures ◽  
Aerial Reconnaissance ◽  
High Precipitation

Abstract This paper provides the first evidence for sea-ice formation in the Cordillera Darwin (CD) fjords in southern Chile, which is farther north than sea ice has previously been reported for the Southern Hemisphere. Initially observed from a passenger plane in September 2015, the presence of sea ice was then confirmed by aerial reconnaissance and subsequently identified in satellite imagery. A time series of Sentinel-1 and Landsat-8 images during austral winter 2015 was used to examine the chronology of sea-ice formation in the Cuevas fjord. A longer time series of imagery across the CD was analyzed from 2000 to 2017 and revealed that sea ice had formed in each of the 13 fjords during at least one winter and was present in some fjords during a majority of the years. Sea ice is more common in the northern end of the CD, compared to the south where sea ice is not typically present. Is suggested that surface freshening from melting glaciers and high precipitation reduces surface salinity and promotes sea-ice formation within the semi-enclosed fjord system during prolonged periods of cold air temperatures. This is a unique set of initial observations that identify questions for future research in this remote area.

scholarly journals Increased summer food supply decreases non-breeding movement in black-legged kittiwakes

2020 ◽  
Vol 16 (1) ◽  
pp. 20190725 ◽  
Author(s):  
Shannon Whelan ◽  
Scott A. Hatch ◽  
David B. Irons ◽  
Alyson McKnight ◽  
Kyle H. Elliott
Keyword(s):  
Breeding Season ◽  
Food Supply ◽  
Light Level ◽  
Food Supplementation ◽  
Reproductive Phenology ◽  
Rissa Tridactyla ◽  
Breeding Behaviour ◽  
Unlimited Supply ◽  
Migration Phenology ◽  
Carry Over

Individual condition at one stage of the annual cycle is expected to influence behaviour during subsequent stages, yet experimental evidence of food-mediated carry-over effects is scarce. We used a food supplementation experiment to test the effects of food supply during the breeding season on migration phenology and non-breeding behaviour. We provided an unlimited supply of fish to black-legged kittiwakes ( Rissa tridactyla ) during their breeding season on Middleton Island, Alaska, monitored reproductive phenology and breeding success, and used light-level geolocation to observe non-breeding behaviour. Among successful breeders, fed kittiwakes departed the colony earlier than unfed controls. Fed kittiwakes travelled less than controls during the breeding season, contracting their non-breeding range. Our results demonstrate that food supply during the breeding season affects non-breeding phenology, movement and distribution, providing a potential behavioural mechanism underlying observed survival costs of reproduction.

scholarly journals Thermodynamics of slush and snow–ice formation in the Antarctic sea-ice zone

2016 ◽  
Vol 131 ◽  
pp. 75-83 ◽  
Author(s):  
Mathilde Jutras ◽  
Martin Vancoppenolle ◽  
Antonio Lourenço ◽  
Frédéric Vivier ◽  
Gauthier Carnat ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Formation ◽  
Antarctic Sea Ice ◽  
The Antarctic

Sea-ice and density-dependent factors affecting foraging habitat and behaviour of Adélie penguins throughout the breeding season

2021 ◽  
Vol 168 (7) ◽  
Author(s):  
Nobuo Kokubun ◽  
Louise Emmerson ◽  
Julie McInnes ◽  
Barbara Wienecke ◽  
Colin Southwell
Keyword(s):  
Sea Ice ◽  
Breeding Season ◽  
Foraging Habitat ◽  
Factors Affecting ◽  
Density Dependent ◽  
Adélie Penguins
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