The Amazon’s canary in the coalmine: what a tropical fish can tell us about climate upheaval

Scientist Adalberto Luis Val’s pioneering research on the tambaqui fish is revealing the effect of climate disruption in Brazil, with global implications for biodiversity and food security

As a boy in rural São Paulo, Adalberto Luis Val used to stare into the lake where his father took him fishing and wonder how all those creatures swimming below stayed alive. One day, he netted a few, put them in a jar, and brought them home to observe. The next morning, they were all dead. Val was devastated but intrigued.

“I needed to know how fish are able to live,” he says.