An extraordinary number and diversity of fish inhabit the Amazon River basin. Many, if not all of them, are of great importance in maintaining the ecosystems found along the river and its tributaries (by the dispersal of tree seeds, for example) as well as supporting both commercial and subsistence fishing. While I was aware that there were migrations of catfish (also known as bagre), I didn’t know that during these migrations, some species cover distances similar to those observed in Atlantic or Pacific salmon migrations. The migrations of fish in the Amazon basin— an essential part of their life cycles—cover distances that fluctuate between 3,700 and 5,000 kilometers, and can take between 18 and 24 months to complete.
In recent years, the watershed has gained new importance as a potential energy center of Peru, with the planning of a large number of dams. The potential placement of these large infrastructure works on the Marañón River (one of the principal tributaries of the Amazon River) has led to several socio-environmental impact studies. The Marañón flows through areas with great terrestrial and aquatic diversity, including territory belonging to the Awajún and Wampis indigenous people, as well as many river settlements that depend on the river for transportation and fishing as both a source of food and income
The river passes through rugged and narrow gorges on its journey towards the Amazon plain. This topography has led to its being called “the Grand Canyon of the Andes”. For this reason, the Marañón River is also known as “Peru’s energy artery“, due to its importance in generating electricity. In April of 2011, the Peruvian government declared the hydroelectric development of the river and its tributaries to be of national and social interest, and made a list of twenty potential sites for infrastructure works for the generation of hydroelectric energy. Many of these places are found in natural mountain gorges called “pongos” in Peru.
According to HydroCoop, the building of hydroelectric dams produces a series of cumulative effects downstream, including alteration of the nutrient dynamics of the water (which in turn has an impact on the fish and fishing populations), and even reduces the amount of sediment that is normally transported by the river and deposited along the coast. This can eventually lead to a change in coastal morphology. One of the areas that seems to be particularly sensitive is the “Pongo de Manseriche“. Located in the Santiago-Comaina Reserved Zone, the 4.8km-long Pongo de Manseriche is the final gorge that the Marañón River flows through before reaching the low-lying Amazon basin. Groups from local villages (and others at several days’ journey) gather here during the bagres migration season to fish.
A recent study by the WWF, financed by the BIO program, established that during the bagres migration season—the dry season lasting from May to October—local populations (to the north and south of the Pongo) may consume up to a half-kilo of fish per person, per day. What’s more, on a good day, a fisherman can earn up to an average of 240 Peruvian Nuevos Soles (approximately $70), which is essential for covering family expenses during the rest of the year. On the other hand, during the rainy season, fishing is a subsistence activity, and per-person fish consumption drops to approximately 80 grams a day. The loss of this ecosystem service would result in people having to spend 12 Peruvian Nuevos Soles on food each day (without including transportation costs). Fish are a critical link between the environmental health of rivers and wetlands and the way of life of millions of people. Altering or interrupting the course of a river threatens the existence of many species and affects the livelihood and survival of many indigenous riverside communities who look to the river and its species as their main source of food.
Interrupting the flow of the river would provide much needed energy sources, but it would also disrupt important sources of income and subsistence for local populations. Therefore, it is important for us to think in terms of sustainable infrastructure, which is to say, infrastructure that causes the least possible damage to the environment, is socially responsible and economically viable, and thereby guarantees the well-being of all in the long run.
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