CADIC   02618
CENTRO AUSTRAL DE INVESTIGACIONES CIENTIFICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Postweaning behaviour of southern elephant seal´s pups at Isla 25 de Mayo, King George Island: wean mass and activity patterns.
Autor/es:
NEGRETE JAVIER; ALEJANDRA TÁRTARA; SEBASTIÁN POLJAK; ESTEBAN SOIBELZON
Lugar:
Leuven
Reunión:
Simposio; XIIth SCAR Biology Symposium; 2017
Institución organizadora:
SCAR
Resumen:
After a suckling period of 23 days southern elephant seals weanlings usually stay on beaches fasting for a variable time of 5 to 8 weeks (Ling & Bryden 1981). This period may be crucial for a successful first foraging trip since pups gradually enter the sea in order to perfect their swimming and diving abilities (Ling & Bryden 1981, Arnbom et al 1993). Not all pups are weaned with same amount of fat reserves, thus in theory the animals should optimize the energy expenditure. The aim of this work was to determine if there are differences in weanling?s activities and/or ambient frequented in relation to their weight at wean. During 2003 breeding season at the Antarctic Specially Protected Area (ASPA) N132 ?Peninsula Potter? we weight 200 weaned pups. From those, we randomly select 15 pups weighting less and 15 weighting more than the average weight (154.5 kg) and we mark them. From December 10 to 27 we carried out daily census of the beach registering in which ambient there were the marked pups (sea vs. land) and the temperature of those places was measure in each period with a mercury thermometer (0.1°C precision). The censuses were carried out from 7 am, every three hours, until 10 pm. We used Spearman Rank Order Correlations to test for association between the number of animals of each group (heavier vs. lighters than the average) in each ambient and the temperature of that ambient. A positive correlation (Spearman?s rho = 0.58, P < 0.05) between both groups of pups and the ground temperature was observed, corresponding to day times when the temperature on the ground is higher (although always below the one in the sea). In contrast, a significant and negative correlation (Spearman?s rho =-0.36 P < 0.05) was registered between sea temperature and weight only for the group of the animals weighting more than the average. From our results it seems that the all weaned pups tend to remain resting on land during daylight hours even when ground temperatures are lower than those of sea. On the other hand, when sea temperature was lower than ground temperature, mostly heavier weanlings were swimming at sea. For this species, survival during the first year of life is low, nearly 45%, (McMahon et al 1999) thus having enough energy stores would appear to be advantageous to cope with the first foraging trips. Moreover, at ?Peninsula Potter? been heavier could improve diving capabilities during the post lactation fasting period since allows to spend more time practicing swim and dive capabilities even during periods of low se water temperatures. To understand the relationship between energy expenditure and experience acquired for foraging, it is necessary to carry out more behavioral studies of weaned pups at Peninsula Potter and examine the relation with survival in the first year of life.