Over 100 Amazon River Dolphins Found Dead Amid Record-High Temperatures

Over 100 Amazon river dolphins were found dead in Lake Tefé over the past week, the Mamirauá Institute for Sustainable Development, a social organization under Brazil’s Ministry of Science, Technology and Innovation, reported. Thousands of dead fish were also found, with experts concerned that the record-breaking high water temperatures and ongoing drought in the region could be connected to the deaths.

According to World Wildlife Fund, of the six species of river dolphins around today, all are considered endangered or critically endangered. River dolphins face many threats, including dams, water pollution, illegal fishing and bycatch.

While increasing water temperatures may also be threatening these vulnerable species, the exact cause of the deaths of more than 100 Amazon river dolphins is still under investigation.

“It’s still early to determine the cause of this extreme event but according to our experts, it is certainly connected to the drought period and high temperatures in Lake Tefé, in which some points are exceeding 39 degrees Celsius (102 degrees Fahrenheit),” Mamirauá Institute said, as reported by CNN.

In addition to high water temperatures, scientists are investigating other potential causes, including contamination from sewage or disease. But they can’t ignore the high water temperature, which has been described as feeling like hot bathwater, The Guardian reported.

While this time of year is typically drier for the Amazon river, the river’s water levels have dropped about 30 centimeters per day for the past two weeks, causing the part of the river in Manaus, Brazil to deplete by 7.4 meters lower than the level during the rainy season, far more than than the average 4.4 meters that the river drops by in the dry season.

“The past month in Tefé has seemed like a science-fiction climate-change scenario,” Daniel Tregidgo, a researcher from the UK who lives in the area, told The Guardian. “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. To know that one has died is sad, but to see piles of carcasses, knowing that this drought has killed over 100, is a tragedy.”

The drought is expected to continue for at least a couple of weeks, which could lead to more deaths of the Amazon river dolphins and other aquatic wildlife.

Researchers and volunteers are trying to rescue surviving river dolphins by transferring them to a cooler part of the river, CNN reported. But this can be challenging because of how remote the area is, and researchers need to first identify whether there is a disease at play that could impact other aquatic life after the transfer.

The prolonged drought has also made the levels of some local waterways too low for boats carrying food and fuel to pass. Further, the drought is impacting local communities’ abilities to fish. At least 15 municipalities have issued a state of emergency, USA Today reported.