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Romero MA, Grandi MF, Koen-Alonso M, Svendsen G, Ocampo Reinaldo M, García NA, Dans SL, González R, Crespo EA. Analysing the natural population growth of a large marine mammal after a depletive harvest. Sci Rep 2017; 7:5271. [PMID: 28706228 PMCID: PMC5509669 DOI: 10.1038/s41598-017-05577-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/30/2017] [Indexed: 11/25/2022] Open
Abstract
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.
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Affiliation(s)
- M A Romero
- Instituto de Biología Marina y Pesquera Almirante Storni, Escuela Superior de Ciencias Marinas - Universidad Nacional del Comahue, San Martín 247, 8520, San Antonio, Oeste (RN), Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - M F Grandi
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de Sistemas Marinos (CESIMAR) CCT-CENPAT-CONICET, Bvd. Brown 2915, 9120, Puerto Madryn, Chubut, Argentina
| | - M Koen-Alonso
- Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, 80 East White Hills Road, St. John's, A1C 5X1, Newfoundland and Labrador, Canada
| | - G Svendsen
- Instituto de Biología Marina y Pesquera Almirante Storni, Escuela Superior de Ciencias Marinas - Universidad Nacional del Comahue, San Martín 247, 8520, San Antonio, Oeste (RN), Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - M Ocampo Reinaldo
- Instituto de Biología Marina y Pesquera Almirante Storni, Escuela Superior de Ciencias Marinas - Universidad Nacional del Comahue, San Martín 247, 8520, San Antonio, Oeste (RN), Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - N A García
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de Sistemas Marinos (CESIMAR) CCT-CENPAT-CONICET, Bvd. Brown 2915, 9120, Puerto Madryn, Chubut, Argentina
| | - S L Dans
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de Sistemas Marinos (CESIMAR) CCT-CENPAT-CONICET, Bvd. Brown 2915, 9120, Puerto Madryn, Chubut, Argentina
- Universidad Nacional de la Patagonia San Juan Bosco, Bvd. Brown 3051, 9120, Puerto Madryn, Chubut, Argentina
| | - R González
- Instituto de Biología Marina y Pesquera Almirante Storni, Escuela Superior de Ciencias Marinas - Universidad Nacional del Comahue, San Martín 247, 8520, San Antonio, Oeste (RN), Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - E A Crespo
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de Sistemas Marinos (CESIMAR) CCT-CENPAT-CONICET, Bvd. Brown 2915, 9120, Puerto Madryn, Chubut, Argentina
- Universidad Nacional de la Patagonia San Juan Bosco, Bvd. Brown 3051, 9120, Puerto Madryn, Chubut, Argentina
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Grandi MF, Crespo EA, Dans SL. Anembryonic Gestation in Wild South American Sea Lion, Otaria flavescens. Anat Histol Embryol 2015; 45:405-8. [PMID: 26497953 DOI: 10.1111/ahe.12215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 09/22/2015] [Indexed: 11/28/2022]
Abstract
We present the first record and description of an anembryonic gestation in a wild South America sea lion, Otaria flavescens (Carnivora, Pinniped). This is the first report of an anembryonic gestation in a wild marine mammal species. This description furthers the knowledge of general aspects of the reproduction of an otariid species, which presents the particularities of delayed implantation and polygynic breeding system, and adds information on a reproductive abnormality in marine mammals.
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Affiliation(s)
- M F Grandi
- Laboratorio de Mamíferos Marinos, Centro Nacional Patagónico-CONICET, Bvd. Brown 2915, 9120, Puerto Madryn, Chubut, Argentina.
| | - E A Crespo
- Laboratorio de Mamíferos Marinos, Centro Nacional Patagónico-CONICET, Bvd. Brown 2915, 9120, Puerto Madryn, Chubut, Argentina.,Universidad Nacional de la Patagonia San Juan Bosco, Bvd. Brown 3051, 9120, Puerto Madryn, Chubut, Argentina
| | - S L Dans
- Laboratorio de Mamíferos Marinos, Centro Nacional Patagónico-CONICET, Bvd. Brown 2915, 9120, Puerto Madryn, Chubut, Argentina.,Universidad Nacional de la Patagonia San Juan Bosco, Bvd. Brown 3051, 9120, Puerto Madryn, Chubut, Argentina
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