Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina

Population size and distribution of Otaria flavescens in central and southern Chubut, Patagonia were determined by aerial censuses conducted during the breeding season in 1989 and 1995 and outside the season. Pup numbers were corrected by means of a linear regression between pup and adult male (AM)...

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Autores principales: Reyes, L.M., Crespo, E.A., Szapkievich, V.
Formato: JOUR
Materias:
Abundance
Chubut
Otaria flavescens
Patagonia
Pup number estimation
Southern sea lion
pinniped
population size
spatial distribution
Argentina
Animalia
Otariidae
Panthera leo
Pinnipedia
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_08240469_v15_n2_p478_Reyes
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_08240469_v15_n2_p478_Reyes2023-10-03T15:39:59Z Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina Reyes, L.M. Crespo, E.A. Szapkievich, V. Abundance Chubut Otaria flavescens Patagonia Pup number estimation Southern sea lion pinniped population size spatial distribution Argentina Chubut Patagonia Animalia Otaria flavescens Otaria flavescens Otariidae Panthera leo Pinnipedia Population size and distribution of Otaria flavescens in central and southern Chubut, Patagonia were determined by aerial censuses conducted during the breeding season in 1989 and 1995 and outside the season. Pup numbers were corrected by means of a linear regression between pup and adult male (AM) numbers obtained from terrestrial censuses carried out in 1994 and 1996. During the 1989 breeding season, 10,557 sea lions occurred at 29 locations; 2,800 (26.3%) were pups. During the 1995 breeding season, 14,887 animals were censused at 32 sites; 3,311 (22.2%) were pups. The corrected pup number increased to 4,852, indicating that around 32% is lost when counting from photographs. The corrected total number increased to 16,483; this fell to less than one half between breeding seasons (November 1990 and 1995). The 1995 breeding season census represents the highest number since 1972 (8,800) and the widest historical dispersion (37 sites year round contrasting with 13 in the late 1940s and 1972). However, the present number is about one half of the 33,000 censused about 50 yr ago. Using a correction factor developed for the north Patagonian population (1.8 x censused number) the present population size in the area can be estimated at around 29,669 individuals. Fil:Crespo, E.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Szapkievich, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_08240469_v15_n2_p478_Reyes
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Abundance
Chubut
Otaria flavescens
Patagonia
Pup number estimation
Southern sea lion
pinniped
population size
spatial distribution
Argentina
Chubut
Patagonia
Animalia
Otaria flavescens
Otaria flavescens
Otariidae
Panthera leo
Pinnipedia
spellingShingle Abundance
Chubut
Otaria flavescens
Patagonia
Pup number estimation
Southern sea lion
pinniped
population size
spatial distribution
Argentina
Chubut
Patagonia
Animalia
Otaria flavescens
Otaria flavescens
Otariidae
Panthera leo
Pinnipedia
Reyes, L.M.
Crespo, E.A.
Szapkievich, V.
Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina
topic_facet Abundance
Chubut
Otaria flavescens
Patagonia
Pup number estimation
Southern sea lion
pinniped
population size
spatial distribution
Argentina
Chubut
Patagonia
Animalia
Otaria flavescens
Otaria flavescens
Otariidae
Panthera leo
Pinnipedia
description Population size and distribution of Otaria flavescens in central and southern Chubut, Patagonia were determined by aerial censuses conducted during the breeding season in 1989 and 1995 and outside the season. Pup numbers were corrected by means of a linear regression between pup and adult male (AM) numbers obtained from terrestrial censuses carried out in 1994 and 1996. During the 1989 breeding season, 10,557 sea lions occurred at 29 locations; 2,800 (26.3%) were pups. During the 1995 breeding season, 14,887 animals were censused at 32 sites; 3,311 (22.2%) were pups. The corrected pup number increased to 4,852, indicating that around 32% is lost when counting from photographs. The corrected total number increased to 16,483; this fell to less than one half between breeding seasons (November 1990 and 1995). The 1995 breeding season census represents the highest number since 1972 (8,800) and the widest historical dispersion (37 sites year round contrasting with 13 in the late 1940s and 1972). However, the present number is about one half of the 33,000 censused about 50 yr ago. Using a correction factor developed for the north Patagonian population (1.8 x censused number) the present population size in the area can be estimated at around 29,669 individuals.
format JOUR
author Reyes, L.M.
Crespo, E.A.
Szapkievich, V.
author_facet Reyes, L.M.
Crespo, E.A.
Szapkievich, V.
author_sort Reyes, L.M.
title Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina
title_short Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina
title_full Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina
title_fullStr Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina
title_full_unstemmed Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Patagonia, Argentina
title_sort distribution and population size of the southern sea lion (otaria flavescens) in central and southern chubut, patagonia, argentina
url http://hdl.handle.net/20.500.12110/paper_08240469_v15_n2_p478_Reyes
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AT crespoea distributionandpopulationsizeofthesouthernsealionotariaflavescensincentralandsouthernchubutpatagoniaargentina
AT szapkievichv distributionandpopulationsizeofthesouthernsealionotariaflavescensincentralandsouthernchubutpatagoniaargentina
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