The Southern River Otter is distributed in the southern temperate forest of South America. This species presents a distribution associated with inland waters in the northern parts of its range, and marine habitat in the southern part of its range. In freshwater habitats otters are associated with the presence of macro-crustaceans from the genus Aegla spp. and Sammastacus spp. (Aued et al. 2003, Cassini et al. 2009, Sepúlveda et al. 2009), which are the otter’s main prey (Medina 1997, Medina-Vogel and Gonzalez-Lagos 2008, Fasola et al. 2009, Rodríguez-Jorquera and Sepúlveda 2011, Franco et al. 2013). Other species of crustaceans, fish and amphibians are also in the otter’s diet but are of marginal occurrence. The species uses rivers with abundant vegetation (Chehebar et al. 1986, Medina-Vogel et al. 2003) and inhabit diverse types of wetlands including Andean lakes, rivers of different sizes, ponds and estuaries. A study using telemetry described an average home range of 11.3 km, with solitary behaviour and a low spatial overlap between individuals of same sex suggesting intrasexual territoriality (Sepúlveda et al. 2007). In the marine range the species uses the marine rocky coast with abundant vegetation cover and low exposure to wind and waves (Sielfeld 1992, Sielfeld and Castilla 1999). In this environment the Southern River Otter is sympatric with the Marine Otter (L. felina), but the latter is segregated by its use of more wave-exposed coastal areas (Sielfeld 1992, Ebensperger and Botto-Mahan 1997). The diet in the marine environment is composed of coastal fish of the genera Harpagifer, Patagonotothen, Eleginops, Cottoperca and crustaceans of the genera Munida, Taliepus, Cancridae, Galatheidae, Lithodidae, Lithodes, Paralomis and Campylonotus (Sielfeld and Castilla 1999, Valenzuela et al. 2013). In general, for both marine and inland waters the Southern River Otter seems to be a specialized aquatic bottom forager preying on slow benthic fish and crustaceans.

The Southern River Otter is listed on CITES Appendix I and listed on the Conservation of Migratory Species of Wild Animals (CMS) Appendix I.

In Chile, the conservation status is listed by the Reglamento de Clasificación de Especies as Endangered in VI, VII, VIII, IX, XIV and X Districts and as Data Deficient in XI and XII Districts (Chile 2011). In Chile, the Subsecretaria de Pesca is the governmental agency responsible of their conservation and management. In those populations inside official protected areas the Corporacion Nacional Forestal is responsible for their conservation. National Action plans in Chile are developed by the Minisiterio del MedioAmbiente, but despite its conservation status, no Action Plan exists for this species at present, which is the most urgent conservation action priority. Hunting is prohibited since 1929 in Chile (Iriarte and Jaksic 1986) and the governmental agency responsible for hunting permits and enforcement is the Servicio Agricola y Ganadero.

In Argentina, the conservation status is Endangered (EN A3cd) (Valenzuela et al. 2012). At national level, the governmental agency responsible of native wildlife conservation and management is the Secretaría de Ambiente y DesarrolloSustentable de la Nación through the Dirección de Fauna Silvestre. The Administración de Parques Nacionales (National Parks Administration) is responsible for conservation of those populations inside the national protected areas, where the species is classified as Special Value Species (APN 1994.). The two populations in Argentina from freshwater and marine habitats are mostly inside national protected areas.
Because of the several agencies involved in the management of the species a strong coordination with clear responsibilities and a work agenda is a major urgency in the short term. Actions recommended for both Chile and Argentina are:

• To develop a Conservation Bi-National Plan for the species;
• To develop specific National Conservation Plans for each country;
• To develop validated Monitoring Programmes in protected and unprotected lands; particularly in Chile where there is no such activity in any population; and
• To reinforce the importance of environmental impact assessment projects in relation to the species in order to adequately determine: a) presence of otter population in areas of projects, and b) in those projects requiring to implement adequate actions to incorporate: 1) measures of monitoring, 2) mitigation and 3) compensation activities.