Overview

Distribution

Southern river otters, Lontra provocax, are only found in central and southern Chile and parts of Argentina. This species has been exterminated from much of its range in Chile by hunting. In Argentina, it is found along the Andes from Tierra del Fuego all the way to the southern part of Neuquen province (Otternet, 1998).

Biogeographic Regions: neotropical (Native )

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Range Description

L. provocax occurs in Argentine and Chilean Patagonian region, between 36°S and 52°S latitude (Chehebar et al. 1986). In Chile, the southern river otter is found from Mahuidanche river (39°S) in the province of Colchagua to the Strait of Magallanes. L. provocax once had an extensive distribution from the Cauquenes and Cachapoal Rivers to the Magellan region in Chile. Currently, the distribution of L. provocax is limited by habitat degradation and human disturbance (Medina 1996). In Argentina, the southern river otter is present along the Andes from the southern part of the province of Neuquen down to Tierra del Fuego (Cabrera 1957; Redford and Eisenberg 1992).
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Historic Range:
Chile, Argentina

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Physical Description

Morphology

L. provocax is a medium sized otter. It ranges from 1000 mm to 1160 mm in total length. Its tail is 350 to 460 mm long. These otters possess webbed feet with strong claws. Their hair has a velvety texture. The guard hairs range in length from 15 to 17 mm, and the under fur is 7 to 8 mm long. The dorsum is a very dark brown, which strongly contrasts with the silvery whitish ventrum. Their nose is diamond-shape with the bottom corner squared off (Otternet, 1998).

Range length: 1000 to 1160 mm.

Other Physical Features: endothermic ; bilateral symmetry

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Ecology

Habitat

L. provocax inhabits both marine and fresh waters. It is found on rocky coasts and in protected canals in areas where there are few waves. It does not live in open coastal areas, but instead prefers coastal and freshwater environments with dense vegetation (Redford and Eisenberg, 1992).

Habitat Regions: terrestrial ; saltwater or marine ; freshwater

Aquatic Biomes: lakes and ponds; rivers and streams; coastal

Other Habitat Features: estuarine

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Habitat and Ecology

Habitat and Ecology
L. provocax is predominantly a freshwater species occurring in freshwater lakes and in rivers and streams. Rest and den sites are found in areas with dense vegetation and an abundance of above-ground roots, small rocks or broken stones, which provide suitable crevices from which the animal can view the adjacent water without being exposed. In the Nahuel Huapi National Park, there were significant heterogeneities in its distribution between river basins, between habitats, between lakes relative to dispersal routes and topography. Their distribution is governed by the distribution of crustacean prey, absence of human habitation, and the presence of introduced American mink Mustela vison, because although there was a positive relationship between the occurrence of mink and huillin in Lake Nahuel Huapi, there was a negative relationship in their occurrence between other lakes.

It also occurs in marine habitats along southern Chile (Sielfeld 1983). Habitat in the Patagonian archipelago consists mainly of rocky coasts and canals protected from waves, where coastal strips of vegetation such as Drimis winteri, Notofagus betuloides, and Maytenus magellanica are present; these features, as well as reduced human disturbance, are thought to be favorable for the establishment of dens (Chehebar et al. 1986; Medina 1996a, 1996b; Sielfeld 1983). In Argentina, L. provocax is associated with dense mature forest with thick undergrowth extending close to shore. Both the above-ground root systems of mature or fallen trees and the dense vegetation cover are important components of L. provocax habitat; absence of these key features may result in absence of otters, even if abundance of prey is not limiting (Chehebar et al. 1986).

The southern river otter diet consists mainly of fish including such species as Cheridon australe, Cyprinus carpio, Galaxias, Notothenia, Oncorhynchus mykiss, Percichthys trucha, Percillia gillissi, Salmo trutta, as well as some crustaceans including Aegla, Camilonotus, Lithodes antartica, Munida, Paralomis granulosa, Parastacus pugnax, and Sammastacus spinifrom. Opportunistic consumption of mollusks (Diplodon chilensis, Fissurela) and birds has also been reported (Chehebar 1982; Chehebar and Benoit 1988; Medina 1996a, 1996b, 1997; Sielfeld 1983).

Breeding is thought to occur in July and August, and young are born in September and October (Housse 1953). In parts of the species' southern range, young can be observed all year (Parera 1996). Litter size average one or two young, but may litters of up to four young have been observed (Sielfeld 1983).

Systems
  • Terrestrial
  • Freshwater
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Trophic Strategy

L. provocax diet varies within the separate habitat types. In a Chilean population, 75% of fecal samples analyzed had fish in them, and 63% had crustaceans. In Argentina the feces showed 99% of scats had crustaceans and only 2% contained fish (Medina, 1998). In addition to fish and crustaceans, southern river otters also eat mollusks and birds (Kruuk, 1995).

Animal Foods: birds; fish; terrestrial non-insect arthropods; mollusks

Primary Diet: carnivore (Piscivore , Eats non-insect arthropods)

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Associations

This species probably acts as an important control on mollusk, fish, and crustacean populations.

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Humans are known predators (Redford and Eisenberg, 1992). There are no reports of non-human predation on this species.

Known Predators:

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Known predators

Lontra provocax is prey of:
Homo sapiens

This list may not be complete but is based on published studies.
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Known prey organisms

Lontra provocax preys on:
non-insect arthropods
Actinopterygii
Mollusca
Arthropoda
Aves

This list may not be complete but is based on published studies.
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Life History and Behavior

Behavior

Perception Channels: tactile ; chemical

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Life Cycle

See Reproduction.

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Life Expectancy

A high proportion of the individuals die before they reach maturity. Only about 1% will survive to reach 10 years of age. Most L. provocax only live a few years (Chanin, 1985).

Range lifespan

Status: wild:
10 (high) years.

Typical lifespan

Status: wild:
3 (low) years.

Average lifespan

Status: wild:
>3 years.

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Reproduction

The mating system of this species has not been reported.

River otters typically breed in the winter and spring, with births taking place the following year. Because there is a delay between mating and implantation of the fertilized eggs, there can be a great variability in the length of pregnancy. Although gestation has been reported to be 10-12 months long, actual embryonic development is around two months (Nowak, 1999).

Females have four nipples and produce one to four young each season, but usually produce only one or two young. L. provocax young are born a helpless, blind and scarcely mobile. Young spend their time in the den either suckling or sleeping. The milk is an extremely rich energy source and the young have a high metabolic rate. They open their eyes at approximately one month and begin to eat solid foods at 7 weeks. They begin to swim at about 3 months of age. They are usually capable of catching their own food within 4 months. The young remain with the family group for the first year before they disperse (Chanin, 1985). Reproductive maturity is attained in the second or third year of life.

Breeding season: Breeding occurs in the winter and spring, with births occuring the following year.

Range number of offspring: 1 to 4.

Average number of offspring: 1-2.

Range gestation period: 10 to 12 months.

Range age at sexual or reproductive maturity (female): 2 to 3 minutes.

Range age at sexual or reproductive maturity (male): 2 to 3 minutes.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous ; delayed implantation

As in all mammals, the female provides milk for her offspring. Young are altricial and are cared for by the mother until they disperse. Other aspects of parental care in this species are not known.

Parental Investment: altricial ; female parental care

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Conservation

Conservation Status

Lontra provocax is listed as an endangered species. This is primarily due to illegal hunting, habitat loss and water pollution (Redford and Eisenberg, 1992).

CITES: appendix i

IUCN Red List of Threatened Species: endangered

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IUCN Red List Assessment


Red List Category
EN
Endangered

Red List Criteria
A3cd

Version
3.1

Year Assessed
2008

Assessor/s
Sepulveda, M., Franco, M., Medina, G., Fasola, L. & Alvarez, R.

Reviewer/s
Hussain, S.A. & Conroy, J. (Otter Red List Authority)

Contributor/s

Justification
This species is considered to be Endangered due to an inferred future population decline due to habitat loss and exploitation. Accelerating habitat destruction and degradation throughout the southern river otter's range is the greatest threat to the species, and is inferred (based on current trends) to lead to a future >50% reduction in population size over the next 30 years (3 generations) for those populations using rivers and lakes (freshwater habitats). Those populations using the southern fjords and islands (marine habitats) of Chile the population may reduce to 50% over the next 30 years due to the use of intensive fishery activities. The distribution of the southern river otter has declined drastically due to combined pressures from the destruction of habitat, removal of vegetation, river and stream canalisation, and extensive dredging. Poaching is still a problem especially south of 43° S latitude and in Tierra del Fuego where there is practically no control of hunting. Extirpation of the river otter began in local basins but has become widespread. The lack of re-establishment of the species probably is due to high mortality or reproductive failure following the dispersal of otters into unsuitable areas. This is resulting in a population that is becoming increasingly fragmented and more susceptible to local extinctions through hunting, habitat destruction, human disturbance, predation by domestic dogs, and demographic or environmental stochastic events. Therefore the present status of southern river otter must be considered precarious.

History
  • 2004
    Endangered
  • 2000
    Endangered
  • 1996
    Vulnerable
  • 1996
    Vulnerable
    (Baillie and Groombridge 1996)
  • 1996
    Vulnerable
  • 1994
    Vulnerable
    (Groombridge 1994)
  • 1990
    Vulnerable
    (IUCN 1990)
  • 1988
    Vulnerable
    (IUCN Conservation Monitoring Centre 1988)
  • 1986
    Indeterminate
    (IUCN Conservation Monitoring Centre 1986)
  • 1982
    Indeterminate
    (Thornback and Jenkins 1982)
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Current Listing Status Summary

Status: Endangered
Date Listed: 06/14/1976
Lead Region: Foreign (Region 10) 
Where Listed: Chile,Argentina


Population detail:

Population location: Chile,Argentina
Listing status: E

For most current information and documents related to the conservation status and management of Lontra provocax, see its USFWS Species Profile

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Population

Population
L. provocax is rare in Lanin, Puelo, and Los Alerces National Parks (Chehebar et al. 1986). Only three core populations remain in the species range: Nahuel Huapi National Park, the coast of Beagle Canal in the Tierra del Fuego National Park, and on Staten Island (Chehebar 1985; Porro and Chehebar 1995). Density of southern river otters averages 0.73 individuals (range 0.71-0.75) per km of coastline in southern Chile (Sielfeld 1992).

Population Trend
Decreasing
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Threats

Major Threats
The southern river otter population has been confirmed from seven isolated areas all of which are threatened by a variety of factors. It has been exterminated through much of its Chilean range by habitat destruction and disturbance through removal of riverbank vegetation, dam construction, river and stream canalization, drainage for agriculture and dredging, as well as excessive hunting practices (Chehebar et al. 1986; Housse 1953; Medina 1996a, 1996b; Porro and Chehebar 1995). Populations have been confirmed in only seven isolated areas all of which are threatened by the above-listed concerns, especially dredging impacts on coastal morphology and the large scale of forest destruction in southern Chile that may be affecting several of the freshwater habitats through severe flooding and deposition of soil on the river beds. While illegal, hunting continues to be prevalent in Chile, particularly south of the Chiloe region, as a single otter pelt may pay the equivalent of 2-3 months wages for an unskilled worker (Miller et al. 1983). Otters are also harvested illegally with shellfish-baited hooks, puyero nets, lances, shotguns, foothold traps, and dogs (Medina, 1996b). Introduction of salmonid species may have an impact on otter diet as they may out compete native fish species and salmonids may be too fast for L. provocax to catch (Chehebar 1985; Chehebar and Benoit 1988; Medina 1996a). Impacts of this shift in prey fish species require further research.

Concern about competition for food and space between Lontra provocax and the introduced American mink Mustela vison was raised when otter abundances were noted to be lower in areas where American mink were present (Chehebar 1985; Chehebar et al. 1986). It has been concluded, however, that competitive effects are unlikely to pose a major threat to the otter as the two species exhibit low overlap in diet (<26%) and habitats used (5-22%), suggesting that they may coexist with little competition (Chehebar and Benoit 1988; Chehebar et al. 1986; Medina 1997). Large scale destruction of forests in southern Chile may be affecting several of its freshwater habitats through severe flooding and deposition of soil on the river beds.
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Management

Conservation Actions

Conservation Actions
Lontra provocax is listed in Appendix I of the CITES. The Chilean Red Data Book of Vertebrates lists the species as being in danger of extinction. It is also listed as Threatened in the Argentine National Wildlife List (Consejo Asesor Regional Patagonico de la Fauna Silvestre) (Porro and Chehebar 1995). Recommended conservation measures include population monitoring, enforcement of anti-poaching legislation, habitat maintenance to conserve abundant mature plant cover along shorelines and establishment of water use restrictions for fishing and boating access (Chehebar 1985; Porro and Chehebar 1995, 1996).

Reintroduction of southern river otters into areas where they were previously exterminated due to excessive hunting could be successful in the above mentioned enforcement of legislation and monitoring programs are carried out (Porro and Chehebar 1995; Medina 1996a). Conservation of the southern river otter will require better education, time allowance for populations to recover, and re-establishment of populations in native habitat (Medina 1996a, 1996b).
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Relevance to Humans and Ecosystems

Benefits

No negastive effects of this species on human populations has been noted.

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L. provocax was harvested for its fur, but it is now illegal to harvest these animals. However, poachers are still a threat to this species (Redford and Eisenberg 1992).

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Wikipedia

Southern river otter

The southern river otter, Lontra provocax, is a species of otter that lives in Chile and Argentina. Although called a "river otter", it inhabits both marine and freshwater environments. It sometimes is considered a subspecies of Lontra canadensis. The southern river otter is listed as endangered, due to illegal hunting, water pollution, and habitat loss.

Physical characteristics[edit source | edit]

This medium-sized otter's body can grow up to 2.5 ft (70 cm) long, with a tail adding about 16 in (40 cm). Body weight averages about 5-10 kg (11-22 lbs). Its fur is dark-brown on the top and has a lighter cinnamon color on its underside.

Behavior[edit source | edit]

Although the female and her young will live in family groups, males are usually solitary. Litter sizes average one to two pups, but up to four can be born at a time. Their diets include fish, crustaceans, mollusks, and birds.

Habitat[edit source | edit]

The southern river otter can be found in marine, freshwater, and terrestrial habitats, but are mostly found in freshwater lakes and rivers having a significant amount of dense vegetation, especially along the shorelines, which must be present to use as cover. Their habitats also need the root systems of mature trees, as well as fallen tree debris.

Threats[edit source | edit]

Southern river otters were vigorously hunted for their pelts throughout the last 100 years. This is the major cause of their current low population numbers and endangered conservation status. Since then, they have not been able to recover due to a number of other threats. At this point, only seven known populations of this species are found throughout Chile and Argentina, and all of the populations are isolated from each other.

The riparian forests and rivers in which these otters are mostly found have been disturbed by human presence. Dam and road construction, as well as stream canalization and drainage for agriculture destroy many acres of what could be habitat for this species.[2] Though Argentina began passing legislation in 1960 to outlaw the hunting of the southern river otter, hunting still does occur because of the lack of enforcement. Hunting is legal and does occur in Chile.

The continual decrease in prey numbers also causes problems for the southern river otter.[3] Some invasive aquatic species that have been introduced into that area are limiting the mollusks and fish available for otter prey. This causes the otters to move to other freshwater systems to hunt for food.

Conservation[edit source | edit]

Several surveys and studies have been performed on the southern river otter to better understand its declining population numbers to be able to prevent the species from becoming extinct. Several of the known populations are found within national forests.

One survey in particular was performed to determine if any of this species live within these protected areas. The author surveyed three parks in Argentina: Lanin, Puelo, and Los Alerces National Parks.[4] The surveyors spoke with people who live and work near these areas, and looked for prints and droppings of the southern river otter, while also looking for signs of the American mink. The mink was introduced into this area and is thought to compete with the southern river otter for food resources and habitat space.[5] The results showed signs of the southern river otter were found in 32 of the 275 surveyed sites within the three parks. Of the 32 confirmed sites, 31 were of dense forest with thick undergrowth near the shorelines of freshwater systems. These results suggest having shoreline vegetation for cover is vital for their survival.

Future directions[edit source | edit]

Future directions for conserving this species include obtaining better information on the southern river otter’s population numbers and locations. If conservationists know where the individuals and families live, enforcement of antipoaching laws, as well as focusing on maintaining and protecting their habitats, will be easier. Captive breeding programs would also be beneficial for this species, to later reintroduce individuals into the areas where they were previously found.

References[edit source | edit]

  1. ^ M. Sepulveda, M. Franco, G. Medina, L. Fasola & R. Alvarez (2008). "Lontra provocax". IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature. Retrieved 10 May 2012. 
  2. ^ Marcelo H. Cassini, Laura Fasola, Claudio Chehébar & David W. Macdonald (2010). "Defining conservation status using limited information: the case of Patagonian otters Lontra provocax in Argentina". Hydrobiologia 652 (1): 389–394. doi:10.1007/s10750-010-0332-6. 
  3. ^ M. A. Sepúlveda, J. L. Bartheld, C. Meynard, M. Benavides, C. Astorga, D. Parra & G. Medina-Vogel (2009). "Landscape features and crustacean prey as predictors of the southern river otter distribution in Chile". Animal Conservation 12 (6): 522–530. doi:10.1111/j.1469-1795.2009.00304.x. 
  4. ^ Claudio E. Chehébar, Adriana Gallur, Guillermo Giannico, María D. Gottelli & Pablo Yorio (1986). "A survey of the southern river otter Lutra provocax in Lanin, Puelo and Los Alerces national parks, Argentina, and evaluation of its conservation status". Biological Conservation 38 (4): 293–304. doi:10.1016/0006-3207(86)90056-X. 
  5. ^ L. Fasola, C. Chehébar, D. W. Macdonald, G. Porro & M. H. Cassini (2009). "Do alien North American mink compete for resources with native South American river otter in Argentinean Patagonia?". Journal of Zoology 277 (3): 187–195. doi:10.1111/j.1469-7998.2008.00507.x. 
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