Yká Ulu IMMA

Size in Square Kilometres

70 106 km2

Qualifying Species and Criteria

Peale’s dolphin – Lagenorhynchus australis

Criterion B(2); C (2)

Dusky dolphin – Lagenorhynchus obscurus

Criterion B(1); C (1, 2)

South American sea lion – Otaria byronia

Criterion B (2); C (1,2)

South American Fur Seal – Arctocephalus australis

Criterion B(2); C (1,2)

Hourglass dolphin – Lagenorhynchus cruciger

Long-finned pilot whale – Globicephala melas edwardii

Criterion C (2)

Marine Mammal Diversity 

Criterion D (2)

Lagenorhynchus australis, Lagenorhynchus obscurus, Otaria byronia, Arctocephalus australis, Megaptera novaeangliae, Orcinus orca, Lagenorhynchus cruciger, Globicephala melas edwardii, Physeter macrocephalus, Balaenoptera borealis, Balaenoptera physalus, Balaenoptera bonaerensis, Balaenoptera acutorostrata, Mirounga leonina

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This IMMA includes the south-east part of the Tierra del Fuego archipelago, the Burdwood Bank and surrounding waters at the southern tip of the south American continent. In this area, water masses from the Pacific and Atlantic Oceans and from the Antarctic Circumpolar Current converge. The presence of more than 20 species of marine mammals have been reported in this region through records of sightings. Of these, two species of dolphins (the Peale’s dolphin Lagenorhynchus australis and the dusky dolphin L. obscurus) and two pinnipeds (the South American sea lion Otaria byronia and the South American fur seal Arctocephalus australis) have resident populations in the area. Additionally, different baleen whale species occur seasonally in the region (Humpback whale Megaptera novaeangliae, Sei whale Balaenoptera borealis and minke whale B. bonaerensis and B. acutorostrata) and the occurrence of at least another six marine mammal species have been frequently recorded.

Description of Qualifying Criteria

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

Dusky dolphin L. obscurus

Historically, the presence of dusky dolphins has been considered occasional in the Tierra del Fuego Archipelago; but during the last two decades, they have become very common in the southern Fuegian coast. From 2009 to 2017, the species was regularly sighted between November and May (Dellabianca et al. 2018). New vessel surveys during winter months confirmed the presence of the species year-round along the southern coast of Isla Grande de Tierra del Fuego (LECOVIS unpublished data). Presence of younger calves have been observed in the area during late spring and summer months.  It remains unclear if local individuals came originally from the Atlantic or Pacific Oceans populations, but groups sighted along the Tierra del Fuego Archipelago represent the southernmost resident population of the species worldwide.

Sub-criterion B2: Aggregations

Peale’s dolphin Lagenorhynchus australis            

The presence of Peale’s dolphins has been documented throughout the entire IMMA since the mid-70s (Goodall et al. 1997a), with the highest number of animals in the southern portion of the Tierra del Fuego Archipelago (Dellabianca et al. 2016). Systematic on-board surveys conducted from 2009 to date suggest that Peale’s dolphins are resident in nearshore waters throughout the year (Ordoñez 2019, unpublished data from the marine mammal group of the Laboratory of Wildlife Ecology and Conservation -LECOVIS- of CADIC-CONICET). The presence of calves has been reported from spring to autumn (Goodall et al. 1997b, Ordoñez 2019). Peale’s dolphins have been strongly associated with coastal giant kelp beds Macrocystis pyrifera which are largely extended along the southern coast of Tierra del Fuego (de Haro & Iñíguez 1997, Goodall et al. 1997a, Lescrauwaet 1997, Schiavini et al. 1997, Viddi & Lescrauwaet 2005).

South American sea lion Otaria byronia and South American fur seal Arctocephalus australis

Both species are resident in the IMMA and many rookeries and breeding colonies are found      along the southern and eastern coast of Isla Grande of Tierra del Fuego and Isla de los Estados (Crespo et al. 2015, Milano et al. 2020a, b). The last abundance estimate was 7684 and 9550 individuals for sea lion and fur seal respectively, and both species showed an increasing population trend (Milano et al. 2020b).

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

South American sea lion Otaria byronia

There are many South American sea lion colonies in this IMMA, and ten colonies were confirmed as breeding colonies in the last aerial survey conducted in 2012 (Milano et al. 2020a).

South American fur seal Arctocephalus australis

All breeding colonies (for pupping, nursing, courtship and mating) of this species within the IMMA are on or around Isla de los Estados (Crespo et al. 2015, Milano et al. 2020b).

Sub-criterion C2: Feeding Areas

Long-finned pilot whale Globicephala melas edwardii

Heatmaps created by combining sighting survey data from the IMMA region, showed that the southeast sector of Tierra del Fuego, eastern sector of the Staten Island and waters adjacent to the Burdwood Bank are the main areas with higher sighting density records for long-finned pilot whales (Becker et al. 2021). All these areas have water depths between 200 and more than 3400 m.  Studies based on the carbon and nitrogen stable isotope composition in bone collagen of stranded Long-finned pilot whale specimens from Tierra del Fuego reveal that the long-finned pilot whale is mainly a teutophagous species. Oceanic squids such as Martialia hyadesi, Kondakovia longimana and Histioteuthis spp. showed the greater isotopic contribution to its diet (Becker et al. 2021). In the same study, the southeast part of Tierra del Fuego, eastern part of the Isla de los Estados and the slope break around the Burdwood Bank offer suitable habitats and feeding areas for this species.

Peale’s dolphin Lagenorhynchus australis

Demersal and bottom fishes such as zoarcids and notothenioids, nearshore pelagic species such as Odonthestes spp. as well as octopus and squid species have been identified as important prey for this species in Tierra del Fuego and it is likely that the highly productive waters in this IMMA support important feeding areas for this species (Schiavini et al. 1997, Riccialdelli et al. 2010).

South American sea lion Otaria byronia and South American fur seal Arctocephalus australis

There are numerous haul out sites and pupping areas for both of these species in the IMMA, and the waters surrounding each haulout are heavily used for foraging trips.  Trophic studies identified the squat lobster Munida gregaria and the fuegian sprat Sprattus fuegensis are among the most important prey for both species although a trophic segregation has been suggested (Paso Viola & Raya Rey 2016).

Criterion D: Special Attributes

Sub-criterion D2: Diversity

These productive waters support at least 14 species of marine mammals, including both cetaceans and pinnipeds, including humpback whale Megaptera novaeangliae, sei whale Balaenoptera borealis, fin whale B. physalus, minke whales B. bonaerensis and B. acutorostrata, Hourglass dolphin Lagenorhynchus cruciger, killer whale Orcinus orca, Long-finned pilot whale Globicephala melas edwardii, dusky dolphin L. obscurus, Peale’s dolphin L. australis, south American sea lion Otaria byronia, southern elephant seal Mirounga leonina, south American fur seal Arctocephalus australis and sperm whale Physeter macrocephalus (Falabella et al. 2009, Dellabianca 2014, Dellabianca & Torres 2015, 2016, 2017; Torres et al. 2018; Dellabianca et al. 2023, Paso Viola unpublished data).

Supporting Information

Acha, E.M., Mianzan, H.W., Guerrero, R.A., Favero, M. & Bava, J. (2004). Marine fronts at the continental shelves of austral South America: physical and ecological processes. Journal of Marine Systems, 44, 83-105. https://doi.org/10.1016/j.jmarsys.2003.09.005

Becker, Y.A., Fioramonti, N.E., Dellabianca, N.A. & Riccialdelli, L. (2021). Feeding ecology of the long-finned pilot whale, Globicephala melas edwardii, in the southwestern Atlantic Ocean, determined by stable isotopes analysis. Polar Biology, 44(8), 1655-1667. https://doi.org/10.1007/s00300-021-02908-2

Campagna, C., Verona, C. & Falabella, V. (2006). Situación ambiental en la ecorregión del Mar Argentino. In: A. Brown, U. Martínez Ortiz, M. Acerbi, J. Corcuera (Eds.) La situación ambiental argentina 2005. Fundación Vida Silvestre Argentina, Buenos Aires, pp. 323-336

Cousseau, M.B. & Perrotta, R.G. (1998) Peces marinos de Argentina: biología, distribución, pesca. INIDEP, Mar del Plata

Crespo, E. A., Schiavini, A. C., García, N. A., Franco‐Trecu, V., Goodall, R. N. P., Rodríguez, D., … & de Oliveira, L. R. (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.

Croxall, J.P. & Woods, A.G. (2002). The importance of the Patagonian Shelf for top predator species breeding at South Georgia. Aquatic conservation: marine and freshwater ecosystems, 12, 101-118. https://doi.org/10.1002/aqc.480

de Haro JC & Iñíguez MA (1997). Ecology and behaviour of the Peale’s dolphin, Lagenorhynchus australis (Peale, 1848), at Cabo Vírgenes (52°309S, 68°289W), in Patagonia, Argentina. Reports of the International Whaling Commission 47:723-727

Dellabianca NA (2014) Ecología y Conservación de Aves y Mamíferos Marinos. En D. Fernández. Campaña “Área Protegida Namuncurá – Banco Burdwood”. Informe de campaña. BO Puerto Deseado 2014, pp. 88-97.

Dellabianca NA & Torres MA (2015). Ecología y Conservación de Aves y Mamíferos Marinos. En N.A. Dellabianca. Campaña “Namuncurá – Banco Burdwood”. Informe de campaña. SB-15 Tango 2015, pp. 28-36. 

Dellabianca NA & Torres MA (2016). Ecología espacial de Aves y Mamíferos Marinos del AMP Namuncurá-Banco Burdwood. En J. Martin y G. Kreps. Campaña “AMP Namuncurá – Banco Burdwood: Primavera 2016”. Informe de campaña. BO Puerto Deseado 2016, pp 34-43.

Dellabianca NA, Pierce GJ, Raya Rey A, Scioscia G, Miller DL, Torres MA, Paso Viola MN, Goodall RNP, Schiavini AC (2016) Spatial models of abundance and habitat preferences of Commerson’s and Peale’s Dolphin in Southern Patagonian Waters. PLoS ONE11:e0163441 

Dellabianca NA & Torres MA (2017). Ecología espacial de Aves y Mamíferos Marinos del AMP Namuncurá-Banco Burdwood. En L. Schejter. Campaña “Banco Burdwood” Buque Oceanográfico ARA Puerto Deseado –PD BB abril 2017, pp 133-145. 

Dellabianca NA, Torres MA, Raya Rey AR (2018) Occurrence of dusky dolphin Lagenorhynchus obscurus in Tierra Del Fuego archipelago over five decades. Polar Biol 41:1895–1900.

Dellabianca NA, Torres MA, Ordoñez C, Fioramonti N, Raya Rey A (2023) Marine protected areas in the Southwest Atlantic: insights from marine top predator communities. Aquatic Conservation: Marine and Freshwater Ecosystems. doi: 10.1002/aqc.3935.

Falabella, V., Campagna, C. & Croxall, J. (2009). Atlas of the Patagonian Sea. Species and spaces. Buenos Aires, Argentina: Wildlife Conservation Society and BirdLife International.

Guerrero RA, Baldoni AG & Benavides HR. (1999). Oceanographic conditions at the southern end of the Argentine continental slope. INIDEP Scientific Document, 5,7-22.

Goodall RNP, de Haro JC, Fraga F, Iñiguez MA, Norris KS. Sightings and behaviour of Peale’s dolphins, Lagenorhynchus australis, with notes on dusky dolphins, L. obscurus, off southernmost South America. Rep int Whal Commn. 1997; 47: 757-775.

Haimovici, M., Brunetti, N.E., Rodhouse, P.G, Csirke, J. & Leta, R.H. (1998) Illex argentinus. In: P.G. Rodhouse, E.G. Dawe, R.K. O’Dor (Eds.) Squid recruitment dynamics. The genus Illex as a model. The commercial Illex species and influences on variability. FAO Fish Tech Pap No 376, Rome, pp 27–58.

Lescrauwaet A (1997) Notes on the behaviour and ecology of the Peale’s dolphin, Lagenorhynchus australis, in the Strait of Magellan, Chile. Reports of the International Whaling Commission 47:747-755

Milano, V. N., Grandi, M. F., Schiavini, A., & Crespo, E. (2020) a. Sea lions (Otaria flavescens) from the end of the world: insights of a recovery. Polar Biology, 43(6), 695-706.

Milano, V. N., Grandi, M. F., Schiavini, A. C. M., & Crespo, E. A. (2020) b. Recovery of South American fur seals fromFuegian Archipelago (Argentina). Marine Mammal Science 1268(6). DOI: 10.1111/mms.12686

Paso Viola MN, Raya Rey A (2016) Primer registro de la dieta del león marino sudamericano de un pelo y del lobo marino sudamericano de dos pelos en el canal Beagle, Tierra del Fuego, Argentina. XI Congreso de la SOLAMAC y 17 Reunión de Especialistas en Mamíferos Acuáticos” del 28 de noviembre al 1 de diciembre de 2016 en Valparaíso, Chile. Presentación poster.

Piola AR & Rivas A (1997). Corrientes en la plataforma continental. El Mar Argentino y sus Recursos Pesqueros 1, 119-132.

Ordoñez C (2019) Abundancia y uso de hábitat del delfín austral Lagenorhynchus australis en la costa sur de Tierra del Fuego, Argentina. Tesis de grado. Universidad de Buenos Aires, Buenos Aires, Argentina.

Riccialdelli L, Newsome SD, Fogel ML, Goodall RNP (2010) Isotopic assessment of prey and habitat preferences of a cetacean community in the southwestern South Atlantic Ocean. Mar Ecol Prog Ser 418:235–248.

Riccialdelli, L., Becker, Y. A., Fioramonti, N. E., Torres, M., Bruno, D. O., Rey, A. R., & Fernández, D. A. (2020). Trophic structure of southern marine ecosystems: a comparative isotopic analysis from the Beagle Channel to the oceanic Burdwood Bank area under a wasp-waist assumption. Marine Ecology Progress Series, 655, 1-27.

Schiavini ACM, Goodall RNP, Lescrauwaet A, Koen Alonso M (1997) Food habits of the Peale’s dolphin, Lagenorhynchus australis; review and new information. Reports of the International Whaling Commission 47:827–833

Torres MA, Ordoñez C, Dellabianca NA (2019). Ecología espacial de Aves y Mamíferos Marinos (2018). En NA Dellabianca, IR Schloss y GA Lovrich. Informe de Campaña “AMP Namuncurá – Banco Burdwood: Comprendiendo la bomba biológica de carbono”. Informe de campaña, BO Austral noviembre 18, pp 66-73.

Viddi FA & Lescrauwaet A (2005) Insights on habitat selection and behavioural patterns of Peale’s dolphins (Lagenorhynchus australis) in the Strait of Magellan, Southern Chile. Aquatic Mammals 31(2):176


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