The fjord is located in one of the largest estuarine areas of the world: the Chilean austral fjords, at a latitude of 45ºS. A century ago this was a region only for brave colonizers. Since then it has been used for different productive purposes such as salmon farming, mariculture, mollusc harvesting and (rather recently) industrial development. This fjord support a large salmon farming industry, it receives the liquid residues of Puerto Aisén (a town of 37000 people, located close to its head). Its also home of a large seaport (Puerto Chacabuco), and it has harmful algal bloom’s problems. Recently, a multinational company requested the Chilean government authorization to install a large industrial complex near the fjord (an aluminium processing plant), further requesting permission to evacuate its industrial residues in the fjord’s water, which has been generating a large discussion in the community. Although both the central and regional Chilean governments state that one of the main characteristics of its environmental policy is wide citizen’s participation, there is no stakeholder’s agreed model for this ecosystem.

The study area is the Aysen watershed, which includes Aysen and Coyaique municipality and has a total surface area of 11456 km². The pattern in annual precipitation show a strong meridional gradient between 4000 mm yr^-1 on the west side of the basin to less than 600 mm yr^-1 the east side, along the border with Argentina.

The Study area: Aysen watershed

Zonal subdivision of coast line and relative annual precipitation regime (AAVV, 2005)

The Aysén watershed contains the following ecoregions: cold steppe, intermedia humid temperate, humid boreal, humid temperate, glaciers-snow and tundra. The most important species within the forests of the watershed and their contribution (as percentages) are:

          • Nothofagus pumilio (lenga) 63.4%
          • Evergreen forests (mixture of species) 32.2 %
          • Nothofagus betuloides (coigue de Magallanes) 4.2%
          • Pilgerodendron uviferun (cipres de las Guaitecas) 0.2 %

Prairies, used mostly for cattle, comprise a 29.3% of the watershed surface followed by areas with snow and glaciers (14%) and areas with no vegetation (7.3%). A smaller fraction of the watershed corresponds to water bodies (1.6%), wetlands (1.2%), urban areas (0.1%) and agriculture land (0.1%).

Besides Aysén the most referenced watersheds around Aysén Fjord is Cuervo and Condor, which are also the ones with biggest watersheds after Aysén watershed. Though the sum of the area of the small watersheds is almost 10 times lower then Aysén watershed area, those areas are also subjected to annual values of precipitation of 4000 mm which is more than 10 times the lowest values of precipitation in Aysén watershed.

River Condor and River Cuervo are also relevant for Estuary dynamics. Cuervo and Cóndor Rivers, have areas smaller than Aysén and corresponding smaller average flows of 99 and 49 m³s^-1.

Watersheds around Aysén Fjord obtained with Mohid Gis and SRTM topography. Rivers obtained from SERPLAC.

Watersheds around Aysén Fjord (obtained in Mohid Gis using SRTM topography)

Small Watersheds around Aysén Fjord (Watersheds obtained with Mohid Gis and SRTM topography, Rivers obtained from SERPLAC)

Aerial photograph from Cuervo and Condor near to Aysén Fjord (source: CEA)

Urban and industrial sources
The Aysén river basin is divided into two main administrative units or counties: Aysén and Coyhaique.  Demographic and socio-economic variables tend to show notable differences between these two counties. The capital, Coyhaique, was founded in 1929. Puerto Aysén was established in 1914 as a small port. An area less than 1% is a part of Lago Verde administrative unit (in the upper part of the watershed) and an area smaller than 5% is a part of Argentina.

Aysén river watershed and the main administrative units. Rivers and watershed were generated by SWAT model and SRTM topography.

The commercial activities have been primarily based on the exploitation of the region’s natural resources and include: fishing and aquaculture, mining, livestock production and ranching, sawmills, and agriculture. Presently where the region of Aysén has a population of 86,697 (2002 census), which represents only 0.6% of the national total. The current population density is 0.7 habitants per square kilometer.

About 80% of the population in Aysén watershed is concentrated in the urban areas (Coyhaique, Puerto Aysén, Puerto Chacabuco). In the region of Aysén, 70% of the total habitants are connected to sewer system. 

Populations in Aysén watershed (source: SERPLAC)

 In 2002, the registered investment initiatives in aquaculture and fishing represented a potential investment of 466 million dollars; in 2003 the registered initiatives represented 153 million dollars. The majority of these initiatives correspond to the final ‘fattening’ phase of salmon production that would occur in the saline waters of Aysén Fjord. These investment initiatives indicate that aquaculture production in the XI region of Aysén is in a process of expansion: by 2010 it is projected that the XI region (and Aysén county in particular) will produce 42% of the national salmonid production (up from 20% today). This growth would be the result of an expected investment of 1400 million dollars in the region.

Spatial distribution of the locations where applications for salmon farming have been submitted. (Data:  SERPLAC, XI Región de Aysén, Regional Government, Chile – Cited in First report on the activities of ECOManage in Chile ).

The production of salmonid species for export occurs in several distinct phases, each requiring certain environmental conditions or ecosystem services. First, fish hatcheries involved in alevin (newly-hatched fish in the larval stage) production require contaminant-free fresh water with temperatures below 12ºC. The raising of salmon from smolt (juvenile fish) to adults require estuarine or protected coastal zones where the salmon can adapt to salt water conditions and achieve a size sufficient for harvesting. There are conditions in the Aysén watershed and Fjord to support the growth of both of these phases in salmon production. Finally, with an increase in production and a desire within the industry to improve the quality of its products, it will be necessary to increase the concentration and production of processing plants. This trend in salmon production is creating a very significant nucleus of salmon production and processing in the area in and around Puerto Aysén and Puerto Chacabuco.

Agriculture data
This sector has traditionally been small-scale and oriented toward local markets, although this is gradually changing. The cold climate restricts agriculture to certain areas of the watershed. Forestry activities include the production of firewood for the heating of homes in the winter. Harvested firewood consists of native southern beech species (Nothofagus spp.). The production of lumber is based on the introduction of non-native conifer species. Although this represents only 0.6% of the national lumber and pulp production, the number of hectares planted with pine is increasing. Cattle ranching have only recently been gaining access to markets outside of the region and country. Although about 1 million hectares (this represents around 10% of Aysen region which has about 10,6 million hectares) are currently used for this activity, the production has been limited by soil erosion and nutrient leaching. Several governmental agencies have programs to boost cattle production in the watershed.  

Historically, cattle and sheep ranching in Aysén has not contributed significantly to regional exports (<1% in 1999), but this is quickly changing. The SAG and other regional authorities are considering a doubling of the number of head of cattle in the watershed within the next few years with little increase in the land area dedicated to this activity. Thus a qualitative change in land use associated with ranching is likely to occur, shifting from extensive to intensive management practices. Primarily riparian areas, show that a cattle ranching has left a mark on the landscape. As there are no governmental restrictions on land-use in the riparian corridor per se, most property owners have not tried to exclude cattle from these areas. In general there are very few fence lines running along the banks of streams and rivers.   As a result, grass is grazed right up to the edge of the water, and there is often a low density of trees or shrubs within 100-300m of the main channel in areas of active cattle ranching.  Aside from direct effects on the vegetation, the presence of cattle leads to the creation of de-vegetated cow paths, the deposition of feces, and possible soil compaction.

Although the Aysén region is often seen as a pristine and undisturbed zone in southern Chile, it has had a history of devastating human impact.  Colonization during last century was accomplished using fire as a management tool.  Wildfires that burned throughout the 1940s have left a long-lasting mark on the watershed. The fires were started intentionally by settlers (and supported by government policies of the time) to clear areas for cattle and sheep. However, fires went out of control, burning freely in the summer months and smoldering underground during the winter. This long-term and subterranean burning has undoubtedly affected the soils of the region in terms of organic content as well as chemical and physical properties. A total of 31% of the watershed surface was affected by these fires. In the decade between 1991 and 2001, fires burned an average of 3366 hectares per year in the XI region, indicating that fire currently represents a relatively minor disturbance the watershed.

Spatial distribution of last century wildfires within Aysén watershed (Source: SERPLAC)