Thousands of fishermen holding cone-shaped nets stood side by side, cheering and chanting as they waited for the signal. Suddenly, they rushed to a large muddy pond and cast their nets, dropping to their knees in the mud. Soon, one proudly held up a fish the length of his arm.
For several hundred years, people have gathered in the southern Mali town of San for Sanké mon, a collective fishing rite in June that begins with animal sacrifices and offerings to the water spirits of Sanké Pond. The rite, with masked dancers and traditional costumes, is on UNESCO's list of intangible cultural heritage.
The marathon session of collective fishing celebrates the town's founding and marks the beginning of the rainy season. But climate change and heat waves are disturbing the tradition.
Sanké pond is starting to disappear, said a village chief, Mamadou Lamine Traoré.
Heat waves in Mali in recent years have caused the pond to start drying out. Temperatures in the town have reached a record this year at 48.5 degrees Celsius (119 degrees Fahrenheit), Emmanuel Doumbia, a local weather observer, told The Associated Press.
The unprecedented heat wave in Mali this year has also led to a surge in deaths. The heat wave began in March as many in the Muslim-majority country observed the Islamic holy month of Ramadan with dawn-to-dusk fasting.
The Red Cross Red Crescent Climate Center said that insufficient data in Mali makes it impossible to know the number of heat-related deaths, but estimated that the toll this year has likely been in the hundreds if not thousands.
An analysis published in April by the World Weather Attribution — an international team of scientists looking at how human-induced climate change impacts extreme weather — said the latest heat wave in the Sahel, a region south of the Sahara that suffers from periodic droughts, is more than just a record-breaker.
Climate change has made maximum temperatures in Burkina Faso and Mali hotter by 1.5 degrees Celsius (2.7 degrees Fahrenheit), the researchers said.
Experts have warned of more scorching weather ahead.
At the latest Sanké mon collective fishing rite, men sweated as they stripped skinny chickens bare and cooked them over reeds, and dancers in sporty knee socks or plastic sandals adjusted armbands adorned with cowrie shells. A national flag waved limply on a weathered pole along the trampled shore.
"This tradition was already established before I was born," said one participant, Amadou Coulibaly, who remains faithful to it despite the growing challenges.
When the rite was added to the UNESCO list in 2009, there were plans to dig deeper into the pond to prevent it from silting up, Traoré said. "But since then, nothing was done and the pond is starting to create problems." It wasn't clear why no action was taken.
The pond's disappearance would threaten not just the centuries-old rite but also the town's economic survival if attention fades, he said.