Dolphins dying again in Amazon lake made shallow by drought

TEFE — The carcass of a baby dolphin lay on the sand bank left exposed by the receding waters in an Amazon lake that has been drying up in the worst drought on record.

Researchers recovered the dead animal on Sept 18 and measured water temperatures that have been rising as the lake's level drops. In the 2023 drought, more than 200 of the endangered freshwater dolphins died in Lake Tefe from excessive water temperatures.

"We've found several dead animals. Last week, we found one a day on average," said Miriam Marmontel, head of the dolphin project at the Mamiraua Institute for Sustainable Development.

"We're not yet associating the deaths with changes in water temperatures, but with the exacerbation of the proximity between human populations, mainly fishermen, and the animals," she said.

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With branches of major rivers in the Amazon basin drying up in 2024’s critical drought, the lake connected to the Solimoes River has shrunk, leaving less room for the dolphins in their favourite habitat.

The lake's main channel is two metres deep and roughly 100 metres wide, and it is used by all the boat traffic, from canoes to heavy ferries, Marmontel said. Two dolphins were killed recently when boats ran into them in the shallow water.

"Nobody thought this drought would come so quickly or imagine that it would surpass last year's drought," fisherman Clodomar Lima said.

While the dolphin deaths are nowhere close to 2023's toll, the dry season has more than a month to go and water levels will continue to decline, the researcher said.

And it is not just the rare dolphin species that are suffering. Riverine communities across the Amazon are stranded by the lack of transport on waters too shallow for boats, and their floating houses are now on solid ground.

Even houses built on stilts over water are now high and dry a distance from the river shore.

Lake Tefe resident Francisco Alvaro Santos said it was the first time ever that his floating house was out of the water.

"Water is everything to us. It is part of our daily lives, the means of transportation for everyone who live(s) here. Without water we are nobody!" Santos said. 

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