Over a hundred dolphins have been discovered dead in Lake Tefé in the Brazilian Amazon in the last week, which alarmed scientists.
This corresponds with a severe drought and record-breaking water temperatures, which have reached 39 degrees Celsius in certain locations.
Highly Unusual Deaths
This alarming occurrence of dolphin mortality was reported by the Mamirauá Institute, a research facility financed by the Brazilian Ministry of Science. A large number of deaths among these aquatic creatures is unusual and causes concern.
The predominant view is that these fatalities are linked to Lake Tefé's record-high temperatures and the Amazon's severe dryness.
Ayan Fleischmann, a geoscience researcher at the Mamirauá Institute, said there are numerous potential causes, including sickness and sewage contamination, that are also being explored.
He did, however, say that water depth and temperature were "certainly a main component" of the mass fatality.
Researchers and activists are attempting to save the remaining dolphins by relocating them from lagoons and ponds on the periphery to the main body of the river, where the water is cooler, but the operation is difficult due to the remoteness of the location.
"Transferring river dolphins to other rivers is not that safe because it's important to verify if toxins or viruses are present [before releasing the animals into the wild]," André Coelho, a researcher at the Mamiraua Institute said.
Residents of this little community in the state of Amazonas described the scene as apocalyptic.
"The past month in Tefé has seemed like a science-fiction climate-change scenario," said Daniel Tregidgo, a British researcher living in the area. "Regular sightings of pink river dolphins are one of the great privileges of living in the heart of the Amazon. Pretty much every time I go to the market to have breakfast, I see them come to the surface and it reminds me why I live here."
Brazil, like the rest of the world, has experienced abnormally severe weather in recent months as a result of human-caused climate disruption and an El Niño.
The south of the country has been flooded by heavy rainstorms, while the north has been parched by an abnormally harsh dry season.
Over the last two weeks, the Amazon, the world's largest river, has dropped by 30cm every day.
The average depth in Manaus at this time of year is 4.4 meters (14 feet) lower than it was during the rainy season. It has already dried up by 7.4 meters this year, which local biologists have termed "absurd."
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Dolphins as Indicator of River's Health
Dolphins are seen to be an indicator of a river's health, which is important for those who live along its banks.
Dolphins have been struggling elsewhere in the Amazon.
Fishermen in Marechal Thaumaturgo, Pará State, rescued two of the mammals that became caught when water levels in the Juruá River dipped to 2.3 meters, the lowest in five years, earlier this month.
Many other species are in distress. This month, social media videos showed a deceased newborn manatee being placed inside a canoe.
Daphne Willems of the conservation group WWF said that this extraordinary species is already endangered, meaning losing so many individuals in such a short space of time is disastrous.
She stated that this tragedy deserved an immediate response and emphasized the significance of the global river dolphin declaration, which is set to be signed on October 24.
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