Enfoque ecológico y comparativo en el monitoreo de pinnípedos (Mammalia: Pinnipedia) en los alrededores de la Estación Científica Pedro Vicente Maldonado, Antártida

Monitoring of pinnipeds around the Pedro Vicente Maldonado Scientific Station (South Shetland islands, Antarctica) was conducted between 2010 and 2014 and resumed in 2023–2024 during the austral summers, focusing on four pinniped species: Arctocephalus gazella, Leptonychotes weddellii, Hydrurga leptonyx, and Mirounga leonina. This study examined population dynamics, spatial distribution, and substrate preferences, particularly for A. gazella. The data analyzed in this study were collected through fixed-width transect surveys across 11 transects (46.8 km in 2023 and 27.0 km in 2024), using direct observation and statistical tests (Wilcoxon, Kruskal-Wallis). A total of 604 pinnipeds were recorded (340 in 2023 and 264 in 2024), with A. gazella (295 individuals) and M. leonina (250 individuals) being the most abundant. Despite interannual fluctuations, the analyses did not reveal significant differences in abundance between years (Wilcoxon, p > 0.05). However, A. gazella exhibited a notable increase (4.7 ind./km) in 2024. Substrate preferences varied among species, with A. gazella predominantly occupying soft substrates (χ² = 95.18, p < 0.05), while M. leonina preferred very soft substrates (χ² = 188.36, p < 0.001) compared to other species. Spatial segregation was observed among species (Kruskal-Wallis, H = 8.62, p = 0.03), with A. gazella concentrated on Barrientos and Robert Islands, and H. leptonyx on Torre Island. The results align with the need for continuous monitoring of these species and highlight the importance of considering potential factors, such as food availability and climatic conditions, that may influence different populations.