Beagle Channel to Cape Horn IMMA

Size in Square Kilometres

26 572 km2

Qualifying Species and Criteria

Peale’s dolphin – Lagenorhynchus australis

Criterion B (2)

Dusky dolphin – Lagenorhynchus obscurus

Criterion B (2)

Burmeister’s porpoise – Phocoena spinipinnis

Criterion B (1)

South American sea lion – Otaria byronia

Criterion B (2)

South American Fur Seal – Arctocephalus australis

Criterion B (2)

Humpback whale – Megaptera novaeangliae

Criterion C (2)

Marine Mammal Diversity 

Criterion D (2)

Lagenorhynchus australis, Lagenorhynchus obscurus, Phocoena spinipinnis, Otaria byronia, Arctocephalus australis, Megaptera novaeangliae, Orcinus orca, Balaenoptera borealis, Balaenoptera bonaerensis, Balaenoptera acutorostrata, Hydrurga leptonyx

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The Beagle Channel and Cape Horn area represents a highly productive region off the southern tip of South America, where the Atlantic, Pacific and Southern Oceans meet. The area sustains at least eleven primary marine mammal species as well as eight supporting species. Among these, three species; Peale’s dolphins (Lagenorhynchus australis), dusky dolphins (L. obscurus) and Burmeister’s porpoises (Phocoena spinipinnis) and two pinnipeds; South American sea lions (Otaria byronia) and South American fur seals (Arctocephalus australis) are resident in the area year-round. Dusky dolphins in this area, represent the southernmost population of the species. Additionally, the area has been identified as a foraging ground for humpback whales (Megaptera novaeangliae).

Description of Qualifying Criteria

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

Burmeister’s porpoises (Phocoena spinipinnis) inhabit both the coast of Tierra del Fuego and the Beagle Channel, where the year-round presence of a small local population has been recorded since 1995 (Goodall et al. 1995, Reyes Reyes et al. 2018). Most sightings been recorded in the inner part of the Beagle Channel, from Bahia Lapataia to Punta Remolino (marine mammal group of the laboratory of Wildlife Ecology and Conservation (MM-LECOVIS) from CADIC-CONICET, unpublished data). Since 2018 a systematic photo-id project has been carried out (Asplanato et al. 2019) and to date more than 50 animals had been identified (some of them were re-sighted in different months) by marks in their dorsal fin and scars on their bodies (Asplanato unpublished data).

Sub-criterion B2: Aggregations

Historically, few sightings of dusky dolphins (Lagenorhynchus obscurus) were reported in the area of the Beagle Channel and Cape Horn (Goodall et al. 1997, Gibbons et al. 2002). Dellabianca et al. (2018) summarized the records from the last 5 decades in the Argentinian Beagle Channel, and gathered information on only 11 sightings in the area between the early 70s and the late 90s. However, from 2002 onward they were more regularly observed in the Beagle Channel and Cape Horn area (Dellabianca et al. 2018, Hucke-Gaete et al. 2022). Surveys conducted from 2009 onwards confirmed the presence of dusky dolphins during summer and fall months (November to April) and more recently, surveys during southern hemisphere winter months in 2017, and 2022 confirmed the presence of dusky dolphins in the months of May, June and August as well, indicating that the species is present in the IMMA year-round (MM-LECOVIS).  Young calves have been observed in the area during late spring and summer months, suggesting that the dolphins are reproducing in the IMMA.

Peale’s dolphins (Lagenorhynchus australis) are distributed from Cape Horn (59° S) to Valparaíso (33° S) in the Pacific Ocean (Aguayo 1975; Goodall et al. al. 1997) and north along the coast of Argentina to Cabo dos Bahias (Brownell et al. 1999). Although the species seems to be very common in certain areas, the population estimate for Peale’s dolphins in the wider Magellan region (including the Beagle Channel) was estimated to be 2,400 individuals (Gibbons et al. 2002). Studies conducted in waters of the Beagle Channel and the Atlantic coast by Dellabianca et al. (2016) showed that 98.5% of sightings of Peale’s dolphin were recorded in waters < 200 m depth. Peale’s dolphins have been regularly recorded in the IMMA since the early 70s (Goodall et al 1997, Dellabianca et al. 2018). Ordoñez (2019) reported a population size of 132 dolphins along the east portion of the Beagle Channel and the southern Atlantic coast of Tierra del Fuego using density surface modelling of sighting data collected during eight scientific cruises on board research vessels between 2009 and 2018. A compilation of data obtained systematically from different surveys and from different sources showed a preference of the Beagle Channel and the Cape Horn areas (Hucke-Gaete et al. 2022) highlighting these areas as priority areas for the species in the Southwestern Atlantic ocean (Dellabianca et al. 2016). The presence of calves has been reported from spring to autumn (Goodall et al. 1997, Ordoñez 2019). Numerous studies have documented a strong association between Peale’s dolphins’ behavioral state and macroalgal forests (Macrocystis pyrifera) (Goodall et al. 1997; Lescrauwaet 1997; De Haro & Iñíguez 1997; Viddi & Lescrauwaet 2005; Heinrich 2006). Although limited, data suggest that their diet is composed of demersal fish and benthic invertebrates that live near or within these kelp forests (Schiavini et al. 1997). Ordoñez et al. 2020 demonstrated that these animals feed and search for prey (40.5% and 14.3% respectively of their total behavioral states) in a portion of the IMMA. The same study showed feeding and foraging activities to be strongly associated with kelp forest habitats.

South American fur seals (Arctocephalus australis) and south American sea lions (Otaria byronia) are resident species in the IMMA, with both rookeries and feeding habitat encompassed by the IMMA. There are many rookeries for both species located on small islands and islets along the Beagle Channel (Crespo et al. 2015, Milano et al. 2020a, b). South American fur seals are present in rocky islets in the Beagle Channel from late February to mid-September at haul-out sites. The number of animals in these sites is highly variable. The maximum recorded number of individuals was 895 in March 1992, within an area of less than 2,000 m2 (Crespo et al., 2015). More recently, the number of counted animals was less than 300 (unpublished data from Paso Viola, unpublished data). For south American sea lions, a total of 467 pups and non-pups were recorded for the islands and islets of the Argentine sector of the Beagle Channel in 2012 (Milano et al. 2020a).

Trophic studies identified the squat lobster Munida gregaria and the fuegian sprat Sprattus fuegensis among the most important prey for both species (Paso Viola & Raya Rey 2016). The IMMA hosts one South American sea lion rookery on Becasses Island in the Beagle Channel, classified as a breeding colony (with more than 20% of pups in the colony and the traditional structure of harems). In 2012, the estimated number of pups was 30, indicating a decrease in pup production compared to a previous aerial survey conducted in 1997 (Milano et al. 2020a).

Criterion C: Key Life Cycle Activities

Sub-criterion C2: Feeding Areas

Humpback Whale Megaptera novaeangliae – The Fuegian Archipelago is an important feeding ground for humpback whales, mainly in the southwestern part of the Strait of Magellan (Gibbons et al. 2003, Acevedo et al. 2011, Haro et al. 2016). During the last decade, more than 155 humpback whales were documented in the Beagle channel between the months of December and June and many of them returned in subsequent summer seasons. On many occasions, they were observed feeding on Fuegian sprat (Sprattus fuegensis) (Torres et al. 2019, Jorobadas del Beagle Photo-id Project, LECOVIS unpublished data).

Criterion D: Special Attributes

Sub-criterion D2: Diversity

The IMMA fulfills the sub-criterion D2 since at least 11 species of marine mammals are regularly found in the area. In addition to the species that have been documented as year-round residents, feeding and breeding in the area, sei whales (Balaenoptera borealis), Antarctic and common minke whales (Balaenoptera bonaerensis and B. acutorostrata) and killer whales (Orcinus orca) have marked seasonal occurrences during summer and autumn-winter months (Capella et al. 1999; Goodall et al. 2008; Dellabianca y Torres 2015, 2016, 2017; Torres et al. 2016; Dellabianca et al. 2023, LECOVIS unpublished data).  The leopard seal (Hydrurga leptonyx) has also been recorded in the area (Aguayo-Lobo et al. 2011, Ferrer 2018) and in the last ten years the number of sightings in the Beagle Channel has increased considerably (Paso Viola, unpublished data).

Supporting Information

Acevedo, J., Plana, J., Aguayo-Lobo, A., & Pastene, L. A. (2011). Surface feeding behavior of humpback whales in the Magellan Strait. Revista de biología marina y oceanografía, 46(3), 483-490

Adami ML, Gordillo S (1999) Structure and dynamics of the biota associated with Macrocystis pyrifera (Phaeophyta) from the Beagle Channel, Tierra del Fuego. Sci Mar 63:183–191

Aguayo-Lobo, A., D. Torres and J. Acevedo. 1998. Los mamíferos marinos de Chile: I. Cetacea [Marine mammals of Chile: I. Cetacea]. Serie Cientifica INACH 48:19–159.

Aguayo-Lobo, A., Acevedo, J., Brito, J. L., Acuña, G. P., Bassoi, M., Secchi, E. R., & Rosa, L. D. (2011). Presence of the leopard seal, Hydrurga leptonyx (de Blaincille, 1820), on the coast of Chile: an example of the Antarctica-south America connection in the marine environment. Oecologia Aust. 15, 69–85

Almandoz, G. O., Hernando, M. P., Ferreyra, G. A., Schloss, I. R., and Ferrario, M. E. (2011). Seasonal phytoplankton dynamics in extreme southern South America (Beagle Channel, Argentina). J. Sea Res. 66, 47–57. doi: 10.1016/j. seares.2011.03.005

Asplanato N, Wells RS, Torres MA, Fioramonti NE, Becker YA, Riccialdelli L, Dellabianca NA (2019). Foto identificación de marsopa espinosa, Phocoena spinipinnis, en el Canal Beagle, Tierra del Fuego, Argentina. XXXII Jornadas Argentinas de Mastozoología. Puerto Madryn, Argentina, 12 al 15 de noviembre.

Capella, J., Gibbons, J., & Vilina, Y. (1999). La orca, Orcinus orca (Delphinidae) en aguas chilenas entre Arica y el cabo de Hornos. An. Inst. Patagon. Serie Cs. Nat. 27, 63–72

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.

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.

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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.

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Fernández M, Jaramillo E, Marquet PA, Moreno CA, Navarrete SA, Ojeda FP, et al. 2000. Diversity, dynamics and biogeography of Chilean benthic nearshore ecosystems: an overview and guidelines for conservation. Rev Chil Hist Nat.  73(4):797–830.

Ferrer, D. G. 2018. Registro de foca leopardo (Hydrurga leptonyx) predando sobre pingüinos en isla Martillo, canal Beagle, provincia de Tierra del Fuego, Argentina. Historia Natural Tercera Serie 8, 63–69.

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Gibbons, J., Capella, J. J., & Valladares, C.  (2003). Rediscovery of a humpback whale, Megaptera novaeangliae, feeding ground in the Straits of Magellan, Chile. Journal of Cetacean Research and Management, 5(2), 203-208.

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Goodall RNP, Benegas LG, Boy CC, Dellabianca N, Pimper L, Riccialdelli L (2008) Review of small cetaceans stranded or incidentally captured on the coasts of Tierra del Fuego, Argentina, over 33 years. Sci Comm Doc SC/60/SM21, International Whaling Commission, June 2008, pp 14 (unpublished).

Goodall, R. N. P., Benegas, L. B., Boy, C. C. & Pimper, L. E. (2008). Baleen whales stranded on the coasts of the Strait of Magellan and Tierra del Fuego, 33 years. Sci Comm Doc SC/60/O11, International Whaling Commission, June 2008, pp 14 (unpublished).

Gordillo S, Rabassa J, Coronato A (2008) Paleoecology and paleobiogeographic patterns of mid-Holocene mollusks from the Beagle Channel (southern Tierra del Fuego, Argentina). Rev Geol Chile 35:321–333

Haro D, Riccialdelli L, Acevedo J, Aguayo-Lobo A, Montiel A (2016) Trophic ecology of humpback whales (Megaptera novaeangliae) in the magellan strait as indicated by carbon and nitrogen stable isotopes. Aquat Mamm 42:233-244.

Heinrich, S. 2006. Ecology of Chilean dolphins and Peale’s dolphins at Isla Chiloe, southern Chile. PhD thesis, University of St Andrews.

Hucke-Gaete, R., L. Bedriñana-Romano, J. Acevedo, F. Viddi, S. Buchan, W. Sielfeld, A. Aguayo-Lobo, P. Zárate, I. Cari, A. Zerbini & J. Redfern. 2022. Diseño para la estimación poblacional de cetáceos en aguas jurisdiccionales de Chile, FIPA 2021-18. Pre-Informe final. Fondo de Investigación Pesquera y de Acuicultura, Subsecretaría de Pesca y de Acuicultura. Unpublished report. 229 pp.

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Rosa, S., Milinkovitch, M.C., Van Waerebeek, K., Berck, J., Oporto, J., Alfaro-Shigueto, J., Van Bressem, M.F., Goodall, N., Cassens, I., 2005. Population structure of nuclear and mitochondrial DNA variation among South American Burmeister’s porpoises (Phocoena spinipinnis). Conservation Genetics 6, 431–443.

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