The clownfish, made famous by the 2003 Pixar film Finding Nemo, will not be able to sustain itself as its home amongst sea anemones is threatened by climate warming. This is what researchers from France's National Centre for Scientific Research (CNRS) found when they studied the fish population’s genetic code and diversity. The international team was able to analyze clownfish populations’ DNA in Papua New Guinea for over a decade, giving them one of the largest samples to study in the history of marine biology, and unfortunately revealing this troubling news.
"The findings reported here were made possible by a huge sampling and DNA sequencing effort that had not been attempted for any marine species before," says WHOI biologist Simon Thorrold, a coauthor of the paper. "The biggest surprise to us was also the most troubling: conservation efforts cannot rely on genetic adaptation to protect clownfish from the effects of climate change. It seems that Nemo won't be able to save himself."
According to the researchers, the families of clownfish that survived and thrived the most during this time were also tied to the healthiest anemone habitats. The surprise came from how dependent on these healthy anemones the clownfish population was. Researchers believe that the anemone habitats of the clownfish contributes, on average, 50% to the fish’s ability to thrive and repopulate. Study co-author Professor Geoff Jones synthesized the team’s findings like this:
“For a clownfish, it's not 'who' you are, but 'where' you are that matters for your future reproductive success. In terms of their genes, clownfish are as good as they can be at finding a suitable habitat. The rest comes down to luck--of being in the right place at the right time. The success of big families that extend over many generations is linked to high-quality habitats, not their shared genes."
Coral and anemone habitats have been suffering dramatically from the affects of climate change, pollution, and our general greedy insensitivity as a species. The stresses on the clownfish have been the subject of research over the past few years because of their relationship to these environments. The team’s findings were published on Nov. 27, 2019, in Ecology Letters.