Newswise — Research has revealed that Amazon river dolphins are in danger due to fishing activities and the proposed construction of new dams and dredging projects. To gain insights into the dolphins' behavior in relation to these threats, scientists utilized satellite tags to track eight dolphins in the Peruvian Amazon.
The study found that an overwhelming 89% of the dolphins' habitat was being utilized for fishing. Moreover, the dolphins were found to be an average of 252km away from the nearest proposed dam and 125km away from the closest proposed dredging site. Although these distances may appear significant, the dolphins' ranges spanned over 50km on average, making them susceptible to the potential impact of dams and dredging that can alter large stretches of river ecosystems.
Furthermore, it is worth noting that many Amazon river dolphins, already classified as an endangered species, reside closer to the proposed sites than the individuals tagged in this study, which consisted of seven males and one female.
The research, conducted by the University of Exeter and Peruvian conservation organization Pro Delphinus, sheds light on the escalating threats faced by the Amazon river dolphins. Dr. Elizabeth Campbell, from the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall, emphasized the growing risks posed by human activities, stating, "It's clear that the Amazon river dolphin is facing increasing threats from humans. Fishing can deplete the dolphins' prey populations, and intentional killing and accidental bycatch also put the dolphins at risk. While bycatch has been recognized as a threat for the past three decades, there is insufficient data on the number of dolphins caught each year."
The threat posed by the construction of dams, particularly in Brazil, is rapidly expanding. Currently, there are 175 dams either operational or under construction in the Amazon basin, and an additional 428 dams are planned within the next three decades.
Furthermore, the construction of the Amazon Waterway has been approved and is currently under contract. This ambitious project involves dredging activities in the four main rivers of the Amazon basin and the expansion of ports to facilitate ship navigation on the Amazon, Ucayali, and Marañón rivers.
However, researchers emphasize that the Peruvian government has a crucial opportunity to safeguard biodiversity. Dr. Campbell expresses the importance of preserving the free-flowing nature of rivers in Peru, creating a safe and healthy habitat not only for river dolphins but also for numerous other species.
Considering that many of these dam and dredging projects are still in the planning stage, the researchers urge the government to take into account the detrimental effects these activities have already had on river species in other regions.
Dr. Campbell also suggests expanding river dolphin tracking programs to cover multiple seasons, tracking more female dolphins in study areas, and increasing the number of dolphins tracked in various locations to enhance our understanding of their movement patterns.
The Amazon River dolphin, found in the basins of the Amazon and Orinoco Rivers, is listed as an endangered species on the IUCN Red List.
The study was funded by the South American River Dolphin Initiative and WWF Peru.
The paper, published in the journal Oryx, is entitled: “Satellite-monitored movements of the Amazon River dolphin and considerations for their conservation.”
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