Southern Patagonia Coastal Waters IMMA

Size in Square Kilometres

2 596 km2

Qualifying Species and Criteria

South American sea lion – Otaria byronia

Criterion B (2); C (1)

South American fur seal – Arctocephalus australis

Criterion B (2); C (1)

Marine Mammal Diversity 

Criterion D (2)

Otaria byronia, Arctocephalus australis, Cephalorhynchus commersonii, Lagenorhynchus obscurus, Lagenorhynchus australis, Orcinus orca, Mirounga leonina, Megaptera novaeangliae, Globicephala melas edwardii, Pseudorca crassidens, Grampus griseus

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The Southern Patagonia Coastal Waters IMMA includes a large coastal, marine and insular sector in the north of the San Jorge Gulf, from Cabo dos Bahías (44º55′, 60º32’W) to a few kilometers south of Quintano Island ( 45°13’S, 66°03’W), including the adjacent maritime zone up to 1.8 nm from the coast. The rocky reefs, 39 islands and 6 islets give this section of the coast distinctive features that differentiate it from the rest of the Chubut coastline. These features enable the presence of a distinctive assemblage of marine mammal species, some being only found in this area.  It includes important haul-out sites for South American fur seals and South American sea lions.

Description of Qualifying Criteria

Criterion B: Distribution and Abundance

Sub-criterion B2: Aggregations

The population of South American fur seals resident in the IMMA is small relative to the original population size which was severely hunted since the 18thcentury. More than 100,000 fur seals were taken in Argentine waters until complete protection in the 20th century. The species started to increase after the harvest stopped in Uruguay in 1991 (Crespo et al 2015). Isla Rasa within this IMMA contains around 60% of the total population of South American fur seals in Argentina, with counts documented by Crespo et al. (2015) as ranging between 2,700 animals in 2001 to almost 13,000 in 2013. Fur seal recovery in Patagonian rookeries was supplied by Uruguayan breeding colonies.

Large aggregations of South American sea lions occur on islands within the IMMA.  At least 43,000 sea lions haul out on 21 rookeries and feed in the surrounding waters (Reyes et al. 1999; Grandi et al. 2015; Romero et al. 2017).

Large numbers of small cetaceans have been recorded inside the IMMA and surrounding areas (Crespo et al. 1997 a,b, 2017; Durante et al. 2020 a,b; Loizaga de Castro et al. 2017; Schiavini et al. 1999).

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

Sea lions, fur seals and several species of small cetaceans give birth, nurse their young, and mate in the IMMA, including dusky, Peale´s and Commerson´s dolphins (Brownell et al 1998; Reyes et al. 1999; Coscarella, 2005; Grandi et al. 2015, 2016; Romero et al. 2017; Soto et al. 2017). The rookeries of fur seals reported an increase in the number of pups born, from 15 pups in 1995, to more than 800 in 2018 (Crespo un published information).  Counts of at least  11,000 South American sea lion pups have been recorded at haul-out sites within the IMMA (Reyes et al. 1999; Grandi et al. 2015; Romero et al. 2017).

Criterion D: Special Attributes

Sub-criterion D2: Diversity

The area includes habitat that supports an important diversity of marine mammal species, both pinnipeds and cetaceans (Crespo et al. 2007). The Parque Interjurisdiccional Marino Costero Patagonia Austral represents an important habitat supporting a wide diversity of marine mammal species of global significance. Eleven species of marine mammals have been reported, of which nine are resident and several more are occasional and use the park for transit (Reyes, 2006).

Supporting Information

Acha, E.M., Mianzan, H.W., Guerrero, R.A., Favero, M and Bava, J., 2004. Marine fronts at the continental shelves of austral South America. Physical and ecological processes. Journal of Marine Systems 44. 83– 105.

Brownell Jr. R.L., E.A. Crespo & M. Donahue. 1998. Peale’s Dolphin Lagenorhynchus australis. Handbook of Marine Mammals, Volume 6: The Second Book of Dolphins and the Porpoises, Ed. S.Ridgway and R.Harrison. pp 105-120.

Coscarella, M. A. (2005). Ecología, comportamiento y evaluación del impacto de embarcaciones sobre manadas de tonina overa Cephalorhynchus commersonii en Bahía Engaño, Chubut. (Ph.D.). Universidad de Buenos Aires, Buenos Aires. 

Coscarella, M.A., Cáceres-Saez, I., Loizaga de Castro, R. y García, N.A. (2019a). Orcinus orca. En: SAyDS– SAREM (eds.) Categorización 2019 de los mamíferos de Argentina según su riesgo de extinción. Lista Roja de los mamíferos de Argentina. Versión digital:

Coscarella, M.A., N. Sueyro, E.A. Crespo & M.G. Pennino. 2021. Small scale habitat modeling for Commerson’s dolphin (Cephalorhynchus commersonii) in northern Patagonia, Argentina. Marine Mammal Science, 10-2021; 1-13.

Chalcobsky, A., N.A. García M.A. Coscarella & E.A. Crespo. 2021. First study of feeding habits of pilot whales (Globicephala melas edwardii) stranded at Caleta Malaspina, Bahía Bustamante, Chubut, Argentina. Marine Mammal Science.

Crespo, E.A., G. Pagnoni and S.N. Pedraza. 1985. Structure of a long-finned pilot whale school stranded in Patagonia. Scientific Reports of the Whales Research Institute, 36:97-106.

Crespo, E.A., Pedraza, S.N., Coscarella, M., Garcia, N.A., Dans, S.L.,  Iñiguez,  M.,  Reyes, L.M., Koen  Alonso  M.,  Schiavini, A.C.M. & Gonzalez, R. 1997a. Distribution  Of Dusky Dolphins (Lagenorhynchus obscurus  Gray, 1828)),  In  The Southwestern Atlantic Ocean With Notes  On  The Size Of Herds. Report Of The International Whaling Commission 47:693-698.

Crespo, E.A., S.N. Pedraza, S.L. Dans, M. Koen  Alonso,  L.M. Reyes, N.A. Garcia, M. Coscarella & A.C.M. Schiavini. 1997b. Direct  and  Indirect Effects of the Highseas  Fisheries  on  the Marine Mammal Populations in the northern and central  Patagonian Coast. J. Northwest Atlantic Fish. Sci, 22:189-207. 

Crespo, E.A., M.N.Lewis & C. Campagna. 2007. Mamiferos marinos: pinnipedios y cetáceos. En: El Mar Argentino y sus recursos pesqueros, Tomo 5 El Ecosistema Marino. INIDEP. Pp 127-150.

Crespo,  E.A., A. Schiavini, N. García, V. Franco-Trecu, N. Goodall, D. Rodríguez, J. Morgante & L.R. Oliveira. 2015. Status, population trend and genetic structure of South American fur seals Arctocephalus australis in southwestern Atlantic waters. Marine Mammal Science, 31(3): 866–890.

Crespo, E. A., Oliveira, L. R. D., & Sepúlveda, M. (2021). South American sea lion (Otaria flavescens, Shaw 1800). In Ecology and conservation of pinnipeds in Latin America (pp. 93-118). Springer, Cham.

Crespo, E.A. & Oliveira, L.R. (2021). South American fur seal (Arctocephalus australis, Zimmermann 1783). Chapter 2. pp 13-27. In: Ecology and Conservation of Pinnipeds in Latin America. Heckel, G., Schramm, Y. (eds) Springer, Cham.

Crespo, E.A., C. Olavarria, N. Dellabianca, M. Iñíguez, V. Ridoux & R.R. Reeves. 2017. Commerson’s Dolphin Cephalorhynchus commersonii (Lacépède, 1804). Red List of Threatened Species.

Durante, C.A., R. Loizaga, H. Cunha & E.A. Crespo. 2020a. Coming back to light: first insight into the genetic diversity of Peale´s dolphins at a Patagonian MPA. Marine Mammal Science 1–9. https: DOI: 10.1111/mms.12671

Durante, C.A., E.A. Crespo & R. Loizaga. 2020b Isotopic niche partitioning between two small cetacean species. MEPS-2020-05-012. Vol 659: 247-259.

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 Journal: 11(3) 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.

Loizaga de Castro, R., F. Saporiti, D.G. Vales, N.A. García, L. Cardona, E. A. Crespo. 2016. What are you eating? A stable isotope insight into the trophic ecology of short-beaked common dolphins in the Southwestern Atlantic Ocean. Mammalian Biology, 81: 571-578.

Loizaga de Castro, R., F. Saporiti, D.G. Vales, L. Cardona, E.A. Crespo. 2017. Using stable isotopes to assess whether two sympatric dolphin species share trophic resources. Marine Mammal Science. DOI:10.1111/mms.12428

Loizaga, R., Vales, D.G., García, N.A. and Crespo, E.A. (2018). Isotopic evidence of structuring killer whale groups along the Southwestern South Atlantic Ocean. IsoEcol, Libro de Resúmenes.

Reyes, L. M. (2006). Cetaceans of central Patagonia, Argentina. Aquatic Mammals, 32(1), 20-30. 

Reyes, L.M., E.A. Crespo & V. Szapkievich. 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.

Rivas A.L. and Pisoni, J.P., 2010. Identification, characteristics and seasonal evolution of surface thermal fronts in the Argentinean Continental Shelf. Journal of Marine Systems 79, 134–143.

Romero M.A., Grandi M.F., Koen-Alonso M., Svendsen, G., Ocampo-Reinaldo M., García N.A., Dans S.L., González R. & Crespo E.A. 2017. Analysing the natural population growth of a large marine mammal after a depletive harvest. Scientific Reports. 7: 5271  | DOI:10.1038/s41598-017-05577-6

Saporiti, F., S. Bearhop, D.G. Vales, L. Silva, L. Zenteno, M. Tavares, E.A. Crespo, L. Cardona. 2015. Latitudinal changes in the structure of marine food webs in the south-western Atlantic Ocean. Estuarine, Coastal and Shelf Science. Marine Ecology Progress Series. 538: 23–34.

Schiavini, A.C.M., Pedraza, S.N., Crespo, E.A., Gonzalez, R. & Dans, S.L. 1999. The abundance of dusky dolphins (Lagenorhynchus obscurus) off north and central  Patagonia,  Argentina, in spring and a comparison with incidental catch in fisheries Results from a pilot  survey  in spring 1995. Marine Mammal Science 15(3):828-840. 

Soto, F.A., Grandi, M.F., García, N.A., Crespo, E.A. & Dans, S.L. 2017. Reproductive Parameters of Female Long-finned Pilot Whales (Globicephala melas edwardii) from the Southwestern Atlantic. Zoological Studies, 56:39-51. doi:10.6620/ZS.2017.56-39. 

Yorio, P. 1998. Zona costera patagónica. En: Canevari, P.; D.E. Blanco, E.H. Bucher, G. Castro y I. Davidson (eds.). Los Humedales de la Argentina. Clasificación, Situación Actual, Conservación y Legislación. Wetlands International Publ. 46, Buenos Aires, Argentina. Pp. 137-167.


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