Analysing the natural population growth of a large marine mammal after a depletive harvest

• Published in: Scientific Reports
• Main Authors: Romero, Maria Alejandra, Grandi, Maria Florencia, Koen Alonso, Mariano, Svendsen, Guillermo, Ocampo Reinaldo, Matías, Garcia, Nestor Anibal, Dans, Silvana Laura, González, Raul Alberto Candido, Crespo, Enrique Alberto
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Nature
• Subjects: OTARIA FLAVESCENS; SOUTH AMERICA SEA LIONS; BAYESIAN STATE-SPACE MODELLING FRAMEWORK; POPULATION GROWTH; HARVEST-DRIVEN DEPLETION; https://purl.org/becyt/ford/1.6; https://purl.org/becyt/ford/1; Canada; Argentina; Grandi; Romero; Northwest Atlantic
• Online Access: http://hdl.handle.net/11336/40980

An understanding of the underlying processes and comprehensive history of population growth after a harvest-driven depletion is necessary when assessing the long-term effectiveness of management and conservation strategies. The South American sea lion (SASL), Otaria flavescens, is the most conspicuous marine mammal along the South American coasts, where it has been heavily exploited. As a consequence of this exploitation, many of its populations were decimated during the early 20th century but currently show a clear recovery. The aim of this study was to assess SASL population recovery by applying a Bayesian state-space modelling framework. We were particularly interested in understanding how the population responds at low densities, how human-induced mortality interplays with natural mechanisms, and how density-dependence may regulate population growth. The observed population trajectory of SASL shows a non-linear relationship with density, recovering with a maximum increase rate of 0.055. However, 50 years after hunting cessation, the population still represents only 40% of its pre-exploitation abundance. Considering that the SASL population in this region represents approximately 72% of the species abundance within the Atlantic Ocean, the present analysis provides insights into the potential mechanisms regulating the dynamics of SASL populations across the global distributional range of the species. Fil: Romero, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina Fil: Grandi, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Koen Alonso, Mariano. Fisheries And Ocean Canada. Northwest Atlantic Fisheries Centre; Canadá Fil: Svendsen, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. ...