Amazon turtles imperilled by dams, mercury pollution and illegal trade

For as long as people have lived in the Amazon, turtles have likely been on the menu. But what was once low-impact subsistence hunting escalated dramatically after the arrival of Europeans. From the 1700s onward, demand for turtle eggs and meat skyrocketed. And the eggs weren’t just for eating: estimates suggest that more than 200 million eggs were harvested for both consumption and oil, fuelling lamps across Europe for two centuries.

This overexploitation led to such dramatic population declines that the Brazilian government eventually stepped in, launching the ambitious Amazon Turtle Program in 1979 — an on-going initiative that has so far protected 70 million turtle hatchlings across the Brazilian Amazon, with the intent of conserving vulnerable species.

But while that program continues to work toward a sustainable future for turtle populations —and for the people who still see chelonians as an important source of protein — three more recent threats loom over Amazonian turtle species: the illegal wildlife trade, widespread hydropower dam construction, and mercury contamination.

Read the full article on Mongabay

The Giant Amazon River Turtle (Podocnemis expansa) is the largest species of neotropical freshwater turtle, and is found throughout the Amazon basin. Overexploited for centuries, the species is making a comeback thanks to conservation initiatives. Photo courtesy of Camila FerraraThe Giant Amazon River Turtle (Podocnemis expansa) is the largest species of neotropical freshwater turtle, and is found throughout the Amazon basin. Overexploited for centuries, the species is making a comeback thanks to conservation initiatives. Photo courtesy of Camila Ferrara

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Amazonian catfish’s 5,000-mile migration endangered by dams

singular Amazonian catfish is capable of an amazing feat: hidden from human eyes, the species travels vast distances over its lifetime, making a round trip covering more than 8,000 kilometers (nearly 5,000 miles), to return to its natal breeding grounds, a new study confirms.

But even as this record-setting feat — the longest freshwater migration in the world — is scientifically confirmed, the species is threatened by hundreds of planned Amazonian dams.

Brachyplatystoma rousseauxii is a commercially valuable catfish species and an apex predator, growing to 3 meters (more than 9 feet) long. Understanding the migratory patterns of the fish, whose range spans six Amazonian countries, “is paramount for designing adequate conservation and management strategies, especially in view of the current and proposed hydroelectric development throughout the Amazon basin,” the researchers write in the Journal of Applied Ecology.

Observations in the 1990s concerning the size distribution of catfish caught along the length of the Amazon River first led researchers to suggest that long-distance homing migration might be taking place, explained study lead author Fabrice Duponchelle of France’s Institute of Research for Development. Subsequent genetic analyses were consistent with that hypothesis, but still didn’t offer definitive proof.

Intrigued by the possibility that catfish might be homing over such vast distances, Duponchelle employed an innovative technique in the new study to get conclusive evidence: chemical analysis of the otolith, a type of ear bone.

As otoliths grow, their chemical composition changes to reflect the background levels of particular chemical elements found in the environment. Like tree rings, the layers of bone relate to their age: the center, innermost layer of otolith is the oldest, and reflects life as a hatchling; the outer edge is the most recent, and reflects the last stage of the fish’s life.

Read the full article, originally published on Mongabay, here

The giant Amazonian catfish is a valuable commercial species, an apex predator, and the world's long distance freshwater fish migration record holder. Photo courtesy of the USGS Columbia Environmental Research CenterThe giant Amazonian catfish is a valuable commercial species, an apex predator, and the world’s long distance freshwater fish migration record holder. Photo courtesy of the USGS Columbia Environmental Research Center.

Ethics, sustainability, and Amazon hydropower: mission impossible?

Latin America’s largest electrical company operates 45 hydroelectric dams, and is responsible for 34 percent of Brazil’s generating capacity. The company, Eletrobras, makes laudable claims about its corporate values, including a commitment to sustainability, and to “operating through a well-balanced environmental, social and ethical responsibility.”

But with grave concerns raised about the environmental and social impacts of hydroelectric dams in the Amazon, and with Eletrobras itself a key actor in the hugely controversial Belo Monte dam, how sustainable are dam-building companies really being? Are the business decisions they make driven by a genuine commitment to sustainability? And, perhaps more importantly, how can we pragmatically assess the true motivations behind those decisions?

Ethical analysis may hold the answers, according to a recent study published in Sustainability. An international team of researchers suggest it is possible to pinpoint what lies behind a company’s decision-making process through a rigorous ethical analysis.

Read the full article, published in May 2016 on Mongabay, here.

Forest loss increased annually for 25 years at oldest Amazon mega-dam

Researchers examining changes in forest cover encircling the Amazon’s oldest mega-dam have found that hundreds of square kilometers of forest have been lost each year of the dam’s 25-year history. The study, published in Applied Geography late in 2015, was undertaken by an international team from the US, Brazil, and the Netherlands. They describe the Tucuruí dam, constructed in the 1980s, as “an ideal case for understanding the long-term impact of mega-dams on rainforest loss.”

Great rivers across the Amazon region carry a mind-boggling amount of water: more than 6,500 cubic kilometers — a box 1,559 square miles on each side — flow from the Amazon River into the Atlantic each year, originating from the Andes, the Guiana Shield, and Central Brazil. That flow has extraordinary hydroelectric generating potential, and Amazonian rivers are today caught up in a frenzy to generate power. More than 400 Amazon dams are already in operation, under construction or proposed, with 256 in Brazil, 77 in Peru, 55 in Ecuador, 14 in Bolivia, six in Venezuela, two in Guyana, and one each in Colombia, French Guyana and Suriname.

My latest article for Mongabay, read more here.