Sighting of a Southern elephant seal &lt;i&gt;Mirounga leonina&lt;/i&gt; in the Toltén River, southern Chile

Maritza Sepúlveda,Chris Harrod,Guido Pavez,Daniel Gomez-Uchida

doi:10.22370/rbmo.2018.53.3.1367

Abstract

The Southern elephant seal (SES) is a marine species that can be found at sea throughout the Southern Ocean on most sub-Antarctic islands. An unusual record of a solitary Southern elephant seal (Mirounga leonina) in freshwater habitat is reported. The seal was found 16 km upstream from the mouth of the Toltén River, in southern Chile (39°9’S; 73°10’W). The individual was classified as a sub-adult male approximately 3 m in length. Potential causes for the unusual presence of the seal in a river include feeding on native estuarine fishes and non-native Chinook salmon or resting. Long lasting resting (5 days) in the Toltén River by the seal may indicate suitable habitat and/or lack of disturbance.

Highlights

The Southern elephant seal (SES, Mirounga leonina Linnaeus, 1758) is the largest pinniped in the world and the most sexually dimorphic mammal (Hindell 2018)
Major breeding colonies are located in South Georgia Island, Kerguelen and Heard Islands, Macquarie Islands and Peninsula Valdés (Boyd et al 1996, Lewis et al 1998, Guinet et al 1999, Slip & Burton 1999, McMahon et al 2005)
The objective of this report was to provide evidence for the presence of a solitary SES found in the Toltén River, a major catchment area located in the Araucanía district in south-central Chile (39°S)

Summary

Introduction

The Southern elephant seal (SES, Mirounga leonina Linnaeus, 1758) is the largest pinniped in the world and the most sexually dimorphic mammal (Hindell 2018). SESs haul out to breed (between August and November) and to molt (between December and February). During the postbreeding (2-3 months) and post-molting (7 months) marine phases, SESs disperse in the sea for foraging (Campagna et al 1993). The SES has a circumpolar distribution in the Southern Hemisphere, with breeding colonies found mainly in the Sub-Antarctic islands near the Antarctic Convergence, with others found in the coastal zone of the southern continents (Hindell 2018). In the case of continental Chile, three breeding colonies are located south of 51°S in the Magallanes Region: Ainsworth Fjord (54°24′S), Jackson Bay (54°26′S) (both located in Seno Almirantazgo in Tierra del Fuego Island) and Poca Esperanza Fjord (52°14′S) (Gibbons & Miranda 2001, Cáceres 2013, Acevedo et al 2016). There are records of solitary individuals along the Chilean coast recorded swimming in waters on the continental shelf from several regions (Sepúlveda et al 2007, Pacheco et al 2011, Acevedo et al 2016, Cárcamo et al 2018), including the sighting of an individual on Easter Island (Aguayo et al 1995)

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