Especies

SA_sea_lions_inglés.jpg

© Ilustration by Pieter Folkens in Encyclopedia of Marine Mammals 3ra Edition

South American sea lion

Scientific name: Otaria flavescens

      It is a sexually dimorphic species. Males typically have a mane, great development of neck muscles, blunt snout, and reach 2.6 m (8.5 ft) long and 350 kg (770 lb). Females lack a mane, they have a slender body, and are about 2 m (6.5 ft) long and 150 kg (330 lb). Fur color may be variable, from dark brown to yellowish light brown. Calves have a dark black fur since they are born until they are two months old. 

     It is typically colonial and polygynous, with an annual cycle divide in a short reproductive phase on land; and a phase in the ocean alternating foraging trips and times of rest on shore. Animals perform seasonal displacements among several haul-outs, in a cyclic manner from one year to the other. Breeding season is from December to February, and the peak of both reproductive individuals on land and births is found during mid-january. 

     

      Depending on the substrate features and density of the colonies, males exhibit various types of mating systems, including female defense, resources or territory defense, lek-like mating systems (or direct competition for dominant status or favorable position within male aggregations), and grouping of subadults males for stealing females. Mature females give birth to an only pup each season within 3-5 days after arriving to the colony after a year-long gestation period. Pup at birth may weigh between 12 and 15 kg (26 - 33 lb). Lactating may last up to 8 to 12 months, although females frequently breast feed a newly born and a one-year old pup (previous season pup). Females reach their sexual maturity at 4-5 years. Males are physiologically mature t 4-6 years, but it is not until they are 9 years old that they can defend a territory and protect a harem. Females live longer than males, with maximum life spans of 22 and 19 years, respectively. Survival rate is also higher in females, with females of each specific age surviving more than males of all ages.  
     Among its predators we find the Orca (Orcinus orca), several species of sharks, and possibly leopard seal (Hydrurga leptonix) and puma (Puma concolor).

_D1A1301web.jpg

Aerial photograph of a colony in Northern Patagonia, Argentina. (Photo: Dario Podestá)

distribucion otaria.jpg

Map showing the worldwide distribution of South American sea lion.

     It is widely distributed in South America. Colonies for this species are found from Zorritos, Peru (4°S) on the Pacific Ocean, to Torres, Brazil (29°S) on the Atlantic Ocean. World population is estimated in no less than 445,000 individuals. This species was intensively hunted for commercial exploitation during the late XIX and early XX century. Despite being an abundant species, current abundance in the Atlantic Ocean is far below the estimated numbers for times previous to exploitation. Tendencies after the end of commercial hunting vary depending on the geographic area. Stocks in Uruguay and Southern Chile continue to reduce; in center Chile they are stable; and stocks in Falklands (Malvinas) Islands, Perú, and northern Chile. Are recovering slowly. Groups inhabiting Patagonia in Argentina are currently in recovery but showing variable rates. The recovery process was accompanied by a spatial recolonization, changing colonies social structure and survival of certain social classes.


     Molecular studies revealed a significative genetic differentiation among colonies in the Atlantic and Pacific Oceans. In the Atlantic, females show distinct subpopulations geographically structured: Uruguay, Patagonia, and Malvinas Islands, whilst males maintain a genetic flow among regions. On the Patagonian coast, distinct females’ populations were detected among colonies in northern and center Patagonia, Santa Cruz, and Malvinas Islands. In a smaller scaler (colonies distributed within ~ 250 km in northern Patagonia) population genetic structure is weak.

     South American sea lions are opportunistic and generalist, with plasticity to adapt and modify their feeding behavior, taking advantage of a wide range of prey along its distribution including benthic and demersal-pelagic fish and invertebrates. Adult and subadult males have a larger action ratio than females and juveniles. Many prey species are of commercial importance in fisheries generating direct and indirect interactions. There is an overlap in resources and /or utilized areas between South American sea lions and artisanal and industrial fisheries. This generates bycatch in gill nets, seine nets and trawling fisheries in many areas. These direct interactions cause mortality. Although historical estimations indicate that mortality values are not high enough to affect population, there is not an updated evaluation of the real problem. Moreover, fisheries affect sea lions indirectly by competence for resources.
      On the other side, South American sea lions are exploited as touristic resource. Even though tourism activities offer a non-lethal alternative and result in an outreach tool, many of the new haul-out areas (arisen from population recovery) are outside a protected area system. Protection is only on land because marine protected areas are scarce. Recently snorkeling activities have been developed with sea lions in Patagonia, generating several behaviors depending on the time of the season. Thus, they require constant monitoring. 

Machinea explotacion lobos (1).jpg
Machinea explotacion lobos 2 (1).jpg

Photographs of commercial hunting in the late 19th and early 20th centuries.

Foto: Kily Durante
Foto: Dario Podestá
Foto: Kily Durante
Foto: Dario Podestá
Foto: Dario Podestá

 

 

 

References

Bartheld JL, Pavés H, Vera C, Manque C, Miranda D. (2008) Cuantificación poblacional de lobos marinos en el litoral de la I a IV Región, Chile. Informe técnico Fondo de Investigación Pesquera IP-IT/2006–50. https :// www.fip.cl/prog_x_year/2006/2006-50.htm. 
- BAYLIS, A.M.M., R.A. ORBEN, J.P.Y. ARNOULD, F. CHRISTIANSEN, G.C. HAYS & I.J. STANILAND. 2015a. Disentangling the cause of a catastrophic population decline in a large marine mammal. Ecology 96: 2834-2847.
- BAYLIS, A. M. M., ET AL. 2015b. Diving deeper into individual foraging specializations of a large marine predator, the southern sea lion. Oecologia 179: 1053-1065. 
- BAYLIS, A.M.M., R.A. ORBEN, D.P. COSTA, J.P.Y. ARNOULD & I. J. STANILAND. 2016. Sexual segregation in habitat use is smaller than expected in a highly dimorphic marine predator, the southern sea lion. Marine Ecology Progress Series 554: 201-211.
- BAYLIS, A.M., R.A. ORBEN, D.P. COSTA, M. TIERNEY, P. BRICKLE & I.J. STANILAND. 2017. Habitat use and spatial fidelity of male South American sea lions during the nonbreeding period. Ecology and Evolution 7: 3992-4002. 
- Campagna C., 1985. The breeding cycle of the southern sea lion, Otaria byronia. Marine Mammal Science, 1 (3), 210-218 
- Campagna C., Le Boeuf B. J., 1988. Reproductive behaviour of southern sea lions. Behaviour, 104 (3-4): 233-261. 
- Campagna. C., Le Boeuf B. J., Cappozzo H. L., 1988. Group raids: a mating strategy of male southern sea lions. Behaviour, 105 (3-4): 223249. 
- Campagna, C., Werner R., Karesh W., Marin M. R., Koontz F., Cook R., Koontz C., 2001. Movements and location at sea of South American sea lions (Otaria flavescens). Journal of Zoology, London, 257: 205220. 
- Cappozzo, H. L., Campagna, C., & Monserrat, J. (1991). Sexual dimorphism in newborn southern sea lions. Marine Mammal Science, 7(4), 385-394.

- Cárdenas-Alayza S. 2018. South American Sea Lion, Otaria byronia. In Encyclopedia of Marine Mammals Würsig, B., Thewissen, J. G. M., & Kovacs, K. M. (Eds.). Academic Press. pp 907-910.

- CÁRDENAS-ALAYZA, S., E.A. CRESPO & L. DE OLIVEIRA. 2016. Otaria byronia. The IUCN Red List of Threatened Species 2016: e.T41665A61948292. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T41665A61948292.en.
- Contreras F, Bartheld J, Montecinos M et al (2014) Cuantificación poblacional de lobo marino común (Otaria flavescens) en el litoral de la XV, I y II Regiones. https://www.researchgate.net/publication/279060858_CUANTIFICACION_POBLACIONAL_DE_LOBO_MARINO_COMUN _Otaria_flavescens_EN_EL_LITORAL_DE_LA_XV_I_y_II_REGIONES_LICITACION_N_4728-14-LP12_Proye cto_2012-6-FAP-1.
- Corcuera J., Monzón F., Crespo E. A., Aguilar A., Raga J. A., 1994. Interactions between marine mammals and coastal fisheries of Necochea and Claromecó (Buenos Aires Province, Argentina). International Whaling Commission, (Special Issue 15): 283-290. 
- Crespi Abril, A., García, N.A., Crespo, E.A., and Coscarella, M.A. (2004). Marine mammals’ consumption by broadnose sevengill shark Notorynchus cepedianus in the northern and central Patagonian shelf. Latin Am. J. Aquat. Mamm. 2(2), 101–107. 
- Crespo E. A., 1988. Dinámica poblacional del lobo marino de un pelo, Otaria flavescens (Shaw, 1800), en el Norte del litoral patagónico. Tesis Doctoral, Fac. Cs. Exactas y Naturales, Univ. de Buenos Aires. Buenos Aires, Argentina, 246 pp. 
- CRESPO, E.A. & M.A. HALL. 2001. Interactions between aquatic mammals and humans in the context of ecosystem management. Marine Mammals: Biology and Conservation (P.G.H. Evans & J.A. Raga, eds.). Kluwer Academic/Plenumm Publishers, New York, USA.
- Crespo E. A., Pedraza S. N., 1991. Estado Actual y tendencia de la población de lobos marinos de un pelo (Otaria flavescens) en el litoral patagónico. Ecología Austral, 1: 87-95. 
- Crespo E. A., Corcuera J., Lopez Cazorla A., 1994. Interactions between marine mammals and fisheries in some fishing areas of the coast of Argentina. International Whaling Commission, Special Issue, 15: 283290. 
- Crespo E. A., Pedraza S. N., Dans S. L., Koen Alonso M., Reyes L. M., Garcia N. A., Coscarella M., Schiavini A. C. M., 1997. Direct  and  indirect effects of the highseas  fisheries on the marine mammal populations in the northern and central patagonian coast. Journal of the Northwest Atlantic Fishery Science 22:189-207. 
- CRESPO, E.A., S.L. DANS, M. KOEN ALONSO & S.N. PEDRAZA. 2007. Interacciones entre mamíferos marinos y pesquerías en la costa argentina. El Mar Argentino y sus recursos pesqueros, Tomo 5, El ecosistema marino (J. I. Carreto & Bremec, eds.). INIDEP, Mar del Plata.
- CRESPO, E.A., D. OLIVA, S. DANS & M. SEPÚLVEDA (EDS.). 2012. Estado de situación del lobo marino común en su área de distribución. Editorial Universidad de Valparaíso, Valparaíso, Chile.
- Dans S. L., Koen Alonso M., Crespo E. A, Pedraza S. N., García N. A., 2003. Interactions between Marine Mammals and High Seas Fisheries in Patagonia Under an Integrated Approach. Pag. 100-115 En: Gales, N., M. - - Hindell y R. Kirkwood (Eds) Marine Mammals: Fisheries; Tourism and Management Issues CSIRO Publishing 

- Dans S. L., Crespo E. A., Pedraza S. N., Koen Alonso M., 2004. Recovery of the south american sea lion population in northern Patagonia. Canadian J. Fisheries and Aquatic Science. Vol. 61:16811690. 
- Dans, S. L., Crespo, E. A., & Coscarella, M. A. (2017). Wildlife tourism: Underwater behavioral responses of South American sea lions to swimmers. Applied Animal Behaviour Science, 188, 91-96.
- FEIJOO, M., E.P. LESSA, R. LOIZAGA DE CASTRO & E.A. CRESPO. 2011. Mitochondrial and microsatellite assessment of population structure of South American sea lion (Otaria flavescens) in the Southwestern Atlantic Ocean. Marine Biology 158: 1857-1867.
- Fernández-Juricic, E., & Cassini, M. H. (2007). Intra-sexual female agonistic behaviour of the South American sea lion (Otaria flavescens) in two colonies with different breeding substrates. acta ethologica, 10(1), 23-28.
- Foro para la Conservación del Mar Patagónico y Áreas de Influencia (2008) Síntesis del estado de conservación del Mar Patagónico y áreas de influencia, Puerto Madryn, Argentina, Edición del Foro.
- Franco‐Trecu, V., Drago, M., Baladán, C., García‐Olazábal, M. D., Crespo, E. A., Cardona, L., & Inchausti, P. (2015). Postharvesting population dynamics of the South American sea lion (Otaria byronia) in the southwestern Atlantic. Marine Mammal Science, 31(3), 963-978.
- Freilich S. Y., 2004. Genetic Diversity and Population Genetic Structure in the South American Sea Lion (Otaria flavescens) from Argentina and the Falkland Islands. Tesis doctoral. 
- Giardino, G. V., Mandiola, M. A., Bastida, J., Denuncio, P. E., Bastida, R. O., & Rodríguez, D. H. (2014). Travel for sex: Long-range breeding dispersal and winter haulout fidelity in southern sea lion males. Mammalian - -Biology, 81(1), 89-95.
- GODOY, J.C. 1963. Evaluación de los Recursos Naturales de la Argentina (Primera Etapa), volumen VIII. Fauna Silvestre, volumen 1. Argentina: Consejo Federal de Inversiones. 
- GRANDI, M.F., S.L. DANS & E.A. CRESPO. 2008. Social composition and spatial distribution of colonies in an expanding population of South American sea lions. Journal of Mammalogy 89: 1218-1228.
- GRANDI, M.F., S.L. DANS, N.A. GARCÍA & E.A. CRESPO. 2010. Growth and age at sexual maturity of South American sea lions. Mammalian Biology 75: 427-436.
- Grandi, M.F., Loizaga de Castro, R., and Crespo, E.A. (2012). Killer whale attacking on South American sea lion associated to a fishing vessel: Predator and prey tactics. Latin Am. J. Aqu. Res. 40(4), 1072–1076. 
- GRANDI, M.F., S.L. DANS & E.A. CRESPO. 2015. The recovery process of a population is not always the same: The case of Otaria flavescens. Marine Biology Research 11: 225-235.
- Grandi, M. F., Dans, S. L., & Crespo, E. A. (2016). Improvement in survivorship: The key for population recovery?. Zoological Studies 55: 9. DOI:10.6620/ZS.2016.55-09
- GRANDI, M.F., R. LOIZAGA DE CASTRO, E. TERÁN, M.R. SANTOS, G. BAILLIET & E.A. CRESPO. 2018. Is recolonization pattern related to female philopatry? An insight into a colonially breeding mammal. Mammalian Biology 89: 21-29.
- HOFFMAN, J.I., G.J. KOWALSKI, A. KLIMOVA, L.J. EBERHART-PHILLIPS, I.J. STANILAND & A.M.M. BAYLIS. 2016. Population structure and historical demography of South American sea lions provide insights into the catastrophic decline of a marine mammal population. Royal Society Open Science 3: 160291. 
- HÜCKSTÄDT, L.A. & M.C. KRAUTZ. 2004. Interaction between southern sea lions Otaria flavescens and jack mackerel Trachurus symmetricus commercial fishery off central Chile: a geostatistical approach. Marine Ecology Progress Series 282: 285-294.
- HÜCKSTÄDT, L.A., R.A. QUIÑONES, M. SEPÚLVEDA & D.P COSTA. 2014. Movement and diving patterns of juvenile male South American sea lions off the coast of central Chile. Marine Mammal Science 30: 1175–1183.
- Jarma, D., Romero, M. A., García, N. A., Svendsen, G., González, R., Dans, S. L., & Crespo, E. A. (2019). Small-scale variation in the diet of the South American Sea lion (Otaria flavescens) in northern Patagonia (Argentina). Regional Studies in Marine Science, 28, 100592.
- Koen Alonso M., Crespo E. A. Pedraza S. N. García N.A., Coscarella M. A., 2000. Food habits of the south american sea lion, Otaria flavescens, off Patagonia, Argentina. Fishery Bulletin, 98 (2): 250-263. 
- Lewis M. N., Ximenez I., 1983. Dinámica de la población de Otaria flavescens (Shaw) en el área de Península Valdés y zonas adyacentes (Segunda parte). Contribución No. 79. Centro Nacional Patagónico, 21 pp. 
- Machado, R., Oliveira, L. R., & Montealegre-Quijano, S. (2014). Incidental catch of South American sea lion in a pair trawl off southern Brazil. Neotropical Biology and Conservation, 10(1), 43-47.
- MANDIOLA, M.A., G. BLANCO & D. RODRÍGUEZ. 2017. Evaluación de interacciones con Mamíferos Marinos en la pesquería de anchoíta certificada bajo estándares del Marine Stewardship Council. Vinculación Tecnológica: de la Universidad Nacional de Mar del Plata al medio socio-productivo. Vol. IV. UNMdP, Mar del Plata, Argentina (ISBN: 978-987-544-494-2)
- Milano, V. N., Grandi, M. F., Schiavini, A. C. M., & Crespo, E. A. (2020). Recovery of South American fur seals from Fuegian Archipelago (Argentina). Marine Mammal Science.

- Muñoz, L., Pavéz, G., Inostroza, P., and Sepúlveda, M. (2011). Foraging trips of female South American sea lions (Otaria flavescens) from Isla Chañaral, Chile. Latin Am. J. Aqu. Mamm. 9(2), 140–144.
- Oliva D, Sepúlveda M, Durán LR, Urra A, Sielfeld W, Moraga R, Pavés G, Muñoz L (2012) Cuantificación poblacional de lobos marinos en las Regiones X –XI y propuesta de escenarios de manejo. Informe Final Proyecto FAP ID 4728–46LP11 
- Oliveira LR, Majluf P (2012) Recuperación de la población de lobos de un pelo después del más fuerte evento de El Niño en la historia. In: Crespo E, Oliva D. Dans, Sepulveda M (eds) Estado de situación del lobo marino común en su área de distribución, Universidad de Valparaíso, Valparaiso, pp 18-34
- OLIVEIRA, L.R. DE, ET AL. 2017.Ancient female philopatry, asymmetric male gene flow, and synchronous population expansion support the influence of climatic oscillations on the evolution of South American sea lion (Otaria flavescens). PLoSONE 12(6): e0179442.DOI:10.1371/journal.pone.0179442.
- Reyes L. M., Crespo E. A., Szapkievich V., 1999. Distribution and population size of the southern sea lion (Otaria flavescens) in central and southern Chubut, Argentina. Marine Mammal Science, 15 (2): 478-493. 
- Riet-Sapriza, F. G., Costa, D. P., Franco-Trecu, V., Marín, Y., Chocca, J., González, B., ... & Hückstadt, L. A. (2013). Foraging behavior of lactating South American sea lions (Otaria flavescens) and spatial–temporal resource overlap with the Uruguayan fisheries. Deep Sea Research Part II: Topical Studies in Oceanography, 88, 106-119.
- RODRÍGUEZ, D.H., ET AL. 2013. Foraging strategies of southern sea lion females in the La Plata River Estuary (Argentina–Uruguay). Deep Sea Research Part II: Topical Studies in Oceanography 88: 120-130.
- ROMERO, M.A. 2011. Rol de los mamíferos marinos en el contexto de la trama trófica del ecosistema del Golfo San Matías e interacciones con las pesquerías de especies demersales. Tesis Doctoral. Universidad Nacional del Comahue. 256 pp.
- ROMERO, M.A., S.L. DANS, R. GONZÁLEZ, G.M. SVENDSEN, N. GARCÍA & E.A. CRESPO. 2011. Solapamiento trófico entre el lobo marino de un pelo Otaria flavescens y la pesquería de arrastre demersal del Golfo San Matías – Patagonia, Argentina. Latin American Journal of Aquatic Research 39: 236-249. 
- ROMERO, M.A., ET AL. 2017. Analysing the natural population growth of a large marine mammal after a depletive harvest. Scientific Reports 7, article number: 5271.
- ROSAS, F. C., PINEDO, M. C., MARMONTEL, M., & HAIMOVICI, M. (1994). Seasonal movements of the South American sea lion (Otaria flavescens, Shaw) off the Rio Grande do Sul coast, Brazil. Mammalia, 58(1), 51-60.
- SCHIAVINI, A. & A. RAYA REY. 2001. Informe de Fauna. Aves y Mamíferos Marinos en Tierra del Fuego. Estado de situación, interacción con actividades humanas y recomendaciones para su manejo. Informe preparado bajo contrato con el Proyecto Consolidación e Implementación del Plan de Manejo de la Zona Costera Patagónica. 
- SECO PON, J.P., ET AL. 2013. Seabird and marine-mammal attendance and by-catch in semi-industrial trawl fisheries in near-shore waters of northern Argentina. Marine and Freshwater Research 64: 237-248.
- Sepúlveda, M., Pérez, M. J., Sielfeld, W., Oliva, D., Durán, L. R., Rodríguez, L., ... & Buscaglia, M. (2007). Operational interaction between South American sea lions Otaria flavescens and artisanal (small-scale) fishing in Chile: results from interview surveys and on-board observations. Fisheries Research, 83(2-3), 332-340.
 Sepúlveda M, Oliva D, Urra A et al (2011) Distribution and abundance of the South American sea lion Otaria flavescens (Carnivora: Otariidae) along the central coast off Chile. Rev Chil Hist Nat 84:97–106
- Sepúlveda, M., Newsome, S. D., Pavez, G., Oliva, D., Costa, D. P., & Hückstädt, L. A. (2015). Using satellite tracking and isotopic information to characterize the impact of South American sea lions on salmonid aquaculture in southern Chile. PloS one, 10(8).
- Sielfeld, W. (1999). Estado del conocimiento sobre conservación y preservación de Otaria flavescens (Shaw, 1800) y Arctocephalus australis (Zimmermann, 1783) en las costas de Chile. Estudios Oceanológicos, 18, 81-96.
- Soto, K. H., & Trites, A. W. (2011). South American sea lions in Peru have a lek‐like mating system. Marine Mammal Science, 27(2), 306-333.
- Szteren, D., Naya, D. E., & Arim, M. (2004). Overlap between pinniped summer diet and artisanal fishery catches in Uruguay. Latin American Journal of Aquatic Mammals, 3(2), 119-125.
- Thompson D., Duck, C.D., McConnell, B.J. and Garrett, J. (1998) Foraging behaviour and diet of lactating female southern sea lions (Otaria flavescens) in the Falkland Islands. Journal of Zoology, London 246: 135-146.
- TÚNEZ, J.I., D. CENTRÓN, H.L. CAPPOZZO & M.H. CASSINI. 2007. Geographic distribution and diversity of mitochondrial DNA haplotypes in South American sea lions (Otaria flavescens) and fur seals (Arctocephalus australis). Mammalian Biology 72: 193-203.
- TÚNEZ, J.I., M.L. CAPPOZZO, M. NARDELLI & M.H. CASSINI. 2010. Population genetic structure and historical population dynamics of the South American sea lion, Otaria flavescens, in North-Central Patagonia. Genetica 138: 831-841.
- Vaz-Ferreira R., 1976. Otaria flavescens (Shaw) South American sea lion. Advisory Committee on Marine Resources research: 1-20. 
- Vaz-Ferreira R., 1982. Otaria flavescens (Shaw), South American sea lion. Mammals in the Seas, FAO, Fisheries, Series IV (5): 477-495. 
- Venegas C, Gibbons J, Aguayo A et al (2002) Distribution and abundance of sea lions and fur seals (Pinnipedia: Otariidae) in the Magellan Region, Chile. An Inst Patagon/Nat 30:67–82
- Ximénez I., 1976. Dinámica de la Población de Otaria flavescens (Shaw) en el Área de Península Valdés y Zonas Adyacentes Provincia del Chubut, República Argentina,  Informe Técnico - Centro Nacional Patagónico.