Nemo and his fellow clownfish do not have the genetic capacity to adapt to changes in their environment, a disturbing finding as coral reefs are changing rapidly as a result of climate change and human activities.
The hero of the famous cartoon "Nemo", recognizable by its bright orange complexion and white stripes, lives "specifically" in coral reef anemones.
"That's why we are worried," says Benoit Pujol, CNRS researcher, co-author of a study published Tuesday in Ecology Letters.
Coral reefs are under threat (20% are already destroyed, 15% are likely to be destroyed in the next 10 years, 20% are threatened within 40 years) due to global warming, pollution, development of coast, overfishing or population growth.
After following individuals from the lagoons of Kimbe Island in Papua New Guinea for 10 years, an international research team discovered that "clown fish lacked the genetic capacity to adapt" to these species. environmental changes.
"Reproductive success in a population is the guarantor of its adaptation," says Pujol.
But the researchers discovered that "the clown fish did not have a genetic variant that would allow it to modify its reproduction". It will not be able to counterbalance, to compensate for the harmful effects on its fecundity of the modifications of its environment by a genetic adaptation.
On the other hand, its habitat strongly influences this reproductive success, add the researchers.
The clownfish remain all their life in the same anemone: they lay their eggs, protect themselves from predators by hiding in the tentacles ...
"It's not too much in the cartoon, but the clownfish has a rather special life cycle," says Pujol.
Each anemone hosts a female, a male and a number of male individuals, not sexually active. "When the female dies, the male becomes female and the largest of the non-sexually active individuals becomes reproductive," he adds.
Researchers now want to try to determine under which conditions and where clownfish breed best.
© 2019 AFP