World Images

Nahuel Huapi is a glacial lake located along the eastern slope of Southern Andean Range with a maximum length of 67 km and a maximum width of 10 km. The lake resembles in its shape "a gigantic amoeba with enormous tentacles extending in all directions to form " a number of arms or fjords. It is also encircled by many smaller lakes. Mountains fringe almost all its coastline; there is a succession of bays and coves, shingle and sandy beaches, perpendicular rocky cliffs, steep promontories, and wooded isthmuses and peninsulas.

The lake offers one of the nicest landscapes in South America, and has been included since 1909 in Nahuel Huapi National Park, the largest of Argentine national parks (785,000 ha). The international city of San Carlos de Bariloche, growing up very fast on the southeastern margin of the lake, attracts every year lots of tourists with pleasant summer weather and winter sports.

The report of a Swedish South-American expedition in 1953-1954 states that "the luxuriant forests of Austrocedrus and Nothofagus surrounding its solitary fjords contrast with the scanty aquatic macrophytes" and that "the scarcity of the latter is partly dependent on the very limited shallow water areas..." This situation, however, changed in the last years when a rapid cultural eutrophication was observed in some small and less deep inlets of the lake, particularly near the city of Bariloche, though the main body of Nahuel Huapi remains oligotrophic. Thus, a lot of macrophytes, especially Scirpus californicus, cover those inlets and are expanding in some arms. Those arms are also rich in nutrients and phytoplankton owing to the result of human activities. Protective measures should be taken before the eutrophication and other kinds of pollution spoil the value of the National Park, where the municipal authorities of Bariloche have jurisdiction of administration (Q).

PHYSICAL DIMENSIONS

Surface area [km2] 646

Maximum depth [m] <300

Water level Unregulated

Length of shoreline [km] 357

Catchment area [km2] 2,758

FLORA

* Emerged macrophytes:

Scirpus californicus, Isoetes savatieri (Q).

* Submerged macrophytes:

Ceratophyllum demersum, Miriophyllum elatinoides (Q).

* Phytoplankton

Winter-spring: Dictyosphaerium pulchellum, Melosira granulata

Summer-autumn: Rhizosolenia eriensis, Dinobryon divergens, D. cylindricum, Melosiragranulata.

FAUNA

* Zooplankton

Rotatoria (Keratella cochlearis, Polyarthra vulgaris, Pompholyx sulcata, Filina longiseta, Gastropus stylifer); Copepoda (Boeckella gracilipes); Cladocera (Bosmina chilensis).

* Benthos (Q)

Decapoda (Samastacus spinifrons, Aegla riolimayana); Amphipoda (Hyallela curvispina); Mollusca (Chilina puelcha, Ch. parchappei, Diplodon patagonicus); Oligochaeta (Chaetogaster limnaei, Stratiodrilus aeglophilus).

* Fish (Q)

Percichthys trutta, P. colhuapiensis, Salmo trutta (introduced), S. gaudneri* (introduced), Diplomistes sp., Hatcheria sp., Aplochiton sp., Galaxias maculatus.

* Economically important.

* Supplementary notes

The biota of all the Andean Patagonic area is characterized by a high degree of endemism, at a species or genus level in some cases but even at a family level in others.

At the beginning of the 20th century, and following an old aboriginal legend, the rumor of a giant creature living in the deep waters of the lake took up. The creature is known locally as Nahuelito. Reported sightings of it predate Nessie and The Lost World (Arthur Conan Doyle). Local aborigines (Mapuche) called another creature el Cuero (leather) for its smooth skin. The neighboring lake Lago Lacar, has also been the site for accounts of another creature, more consistent with a plesiosaur, with aborigines describing it as a sea-cow with teeth all around it.

Members of the Buenos Aires Zoo visited the lake in 1922 trying to corroborate the reports of sightings of the prehistoric animal, but found no evidence to support the theory of such a creature.