River of Voices: Dredging Threatens Amazon Turtle Communication

In the Tapajós River basin, Brazil, researchers are discovering the complex communication of Amazon river turtles, particularly the P. expansa species. These turtles coordinate hatching using vocalizations, enabling synchronized digging from nests nearly a meter deep. However, planned dredging for a major waterway project threatens this delicate system.

The proposed expansion of the Tapajós River’s navigable length—from 345 to 1,789 kilometers—would facilitate the transport of millions of tons of soy and corn annually via large barges. While the government has paused the project for consultation with affected Indigenous communities following protests, concerns remain. Dredging not only disrupts turtle communication but also alters beach composition, impacting egg incubation, and potentially displacing turtles due to increased boat traffic.

Beyond turtles, the project poses risks to other vulnerable species like Amazon river dolphins and manatees, as well as impacting Indigenous lands and protected areas. Conservation efforts, including a program monitoring nesting sites, have seen a 95% increase in hatchlings over four decades, with over a million turtles born at the Monte Cristo site in 2025 alone.

However, these gains are jeopardized by the potential for increased noise pollution and habitat alteration. The future of these “river voices” hangs in the balance as development plans progress.