The clown fish, popular for their leading role in the movie ‘Looking for Nemo’, shrink to survive thermal stress and also to avoid ‘social conflicts’,
A study led by the University of Newcastle measured the length of 134 clown fish monthly for five months and monitored the water temperature every 4-6 days during a marine heat wave increasingly common due to climate change. The field work was carried out at the Mahonia Na Dari Conservation and Research Center, in Kimbe Bay, Papua New Guinea.
Published in Science Advances magazine, they reveal the remarkable capacity of clown fish to shrink, that is, to shorten, in response to thermal stress.
This size decrease increased the survival possibilities of individuals by up to 78 %. In a moving discovery, they also demonstrate that coordination is important for clown fish, since they are more likely to survive heat waves when they shrink along with their reproductive partner.
This is the first time that a coral reef fish has been shown to reduce the length of your body in response to environmental and social conditions.
They do not lose weight, they shrink
Melissa Versteeg, a doctoral researcher at the Faculty of Natural and Environmental Sciences of the University of Newcastle, directed the study. “It is not just about thinning in stress conditions, but these fish are actually shrinking. We still do not know exactly how they do it, but we do know that some other animals can also do it. For example, sea iguanas can reabsorb part of their bone material to also shrink in times of environmental stress.
We were so surprised to observe the shrink in these fish that, to ensure, we measure each of them repeatedly for a period of five months. Finally, we discovered that it was very common in this population. During our study, 100 fish of the 134 we study shrunk.
It was surprising to see the speed with which clown fish adapt to a changing environment and we witness the flexibility with which they regulate their size, both individually and in reproductive pairs, in response to thermal stress, an effective technique to survive, “he explained in a statement.
