scholarly journals Inferring Variation in Southern Elephant Seal At-Sea Mortality by Modelling Tag Failure

2020 ◽  
Vol 7 ◽  
Author(s):  
Angus F. Henderson ◽  
Clive R. McMahon ◽  
Rob Harcourt ◽  
Christophe Guinet ◽  
Baptiste Picard ◽  
...  
Keyword(s):  
Elephant Seal ◽  
Southern Elephant Seal

Interdependence of social structure and demography in the southern elephant seal colony of Península Valdés, Argentina

2009 ◽  
Vol 25 (3) ◽  
pp. 681-692 ◽  
Author(s):  
Mariano A. Ferrari ◽  
Mirtha N. Lewis ◽  
Miguel A. Pascual ◽  
Claudio Campagna
Keyword(s):  
Social Structure ◽  
Elephant Seal ◽  
Southern Elephant Seal

scholarly journals The northernmost haulout site of South American sea lions and fur seals in the western South Atlantic

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Natália Procksch ◽  
M. Florencia Grandi ◽  
Paulo Henrique Ott ◽  
Karina Groch ◽  
Paulo A. C. Flores ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Elephant Seal ◽  
Southern Elephant Seal ◽  
South American ◽  
Mirounga Leonina ◽  
Sea Lions ◽  
Significant Difference ◽  
Northern Portion ◽  
Kernel Density Analysis

AbstractWe present estimates of the seasonal and spatial occupation by pinnipeds of the Wildlife Refuge of Ilha dos Lobos (WRIL), based on aerial photographic censuses. Twenty aerial photographic censuses were analysed between July 2010 and November 2018. To assess monthly differences in the numbers of pinnipeds in the WRIL we used a Generalized Linear Mixed Model. Spatial analysis was carried out using Kernel density analysis of the pinnipeds on a grid plotted along the WRIL. Subadult male South American sea lions (Otaria flavescens) were the most abundant pinniped in the WRIL. Potential females of this species were also recorded during half of the census. The maximum number of pinnipeds observed in the WRIL was 304 in September 2018, including an unexpected individual southern elephant seal (Mirounga leonina), and a high number of South American fur seal yearlings (Arctocephalus australis). However, there was no statistically significant difference in counts between months. In all months analysed, pinnipeds were most often found concentrated in the northern portion of the island, with the highest abundances reported in September. This study confirms the importance of the WRIL as a haulout site for pinnipeds in Brazil, recommends that land research and recreational activities occur in months when no pinnipeds are present, and encourages a regulated marine mammal-based tourism during winter and spring months.

scholarly journals Breeding Colony Dynamics of Southern Elephant Seals at Patelnia Point, King George Island, Antarctica

2020 ◽  
Vol 12 (18) ◽  
pp. 2964
Author(s):  
Katarzyna Fudala ◽  
Robert Józef Bialik
Keyword(s):  
Statistical Tests ◽  
Ground Level ◽  
Elephant Seal ◽  
South Shetland Islands ◽  
Southern Elephant Seal ◽  
King George Island ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
Physical Barriers ◽  
Population Counts

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.

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