Río Gallegos is a river in the Argentinian province Santa Cruz in southern Patagonia. The river results from the meeting of Río Rubens and Río Penitentes nearby the Chilean border and empties after 180 km length into the Atlantic Ocean. On the estuary lies the city of the same name Río Gallegos, the capital of the province. The river Río Gallegos results from the ice age, 6,000 til 7,000 years ago.
The estuary extends over an area of 200 sq. km, the maximum depth in this area measures 20 metres, the salt content lies at 31.8 g/l. The biological richness makes the estuary a site of great international importance, on a par with other areas along the migration route critical for shorebird conservation.
The estuary gives shelter and sustenance to a significant proportion of the world’s population of species such as Magellanic Plover (Pluvianellus socialis), Hooded Grebe (Podiceps gallardoi), an endangered endemic found almost exclusively in Santa Cruz, and Magellanic Oystercatcher (Haematopus leucopodus), all of them endemic to southern Patagonia.
In addition, it is a site used by large numbers of three other shorebird species: White-rumped Sandpiper (Calidris fuscicollis), Red Knot (Calidris canutus), and Hudsonian Godwit (Limosa haemastica). These three arrive from the northern hemisphere and use the estuary as a migration stopover during the non-breeding season. The margins of the estuary are also the habitat of other equally important species such as Ruddy-headed Goose (Chloephaga rubidiceps), Austral Canastero (Asthenes anthoides) and White-bridled Finch (Melanodera melanodera).
The island situated in the mouth of the estuary (Deseada Island) is a breeding place for species such as Magellanic Penguin (Spheniscus magellanicus), Imperial Cormoran (Phalacrocorax atriceps) and Dolphin Gull (Leucophaeus scoresbii).
Part of the estuary is surrounded by extensive salt marsh vegetation, mainly Sarcocornia perennis, forming a dynamic system working as a buffer zone that becomes important for the ecosystem and for the people living nearby. It also accumulates and retains sediment, which generates an indispensable supply for thousands of birds.
As this ecosystem like others, responds to changing environmental conditions, it is extremely necessary to build a commitment with the citizens and government towards sustainable development and use of the area for settlement, tourism, agriculture and fishery.
Ambiente Sur Association is a non profit organization created to work in aspects related with conservation issues. Many of its staff members have been working since at least 10 years ago for the lake from different institutions such as the university, the municipality or individually. All these years of experiences and work with important achievements (creations of the Natural Urban Reserve, the Migratory Bird Reserve; their inclusions in the Western Hemisphere Shorebird Reserve Network, several scientific papers, dissemination of information, development of environmental education initiatives, etc.) give the organization know how, tools and contacts to approach problems related to the estuary and its environment.