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A tiny fish, measured (Photo: Robin Baranowski/NPS Photo, CC BY-SA 2.0 via flickr.com)
Image: CC BY-SA 2.0/Robin Baranowski/NPS Photo

Tiny fish, big skills.

Klaus Esterluß
December 3, 2014

The killifish takes the lead as one of the animals that can most effectively adapt to a changing environment.

https://p.dw.com/p/1DyH4

It may look tiny and insignificant, and its funny name is certainly doing the fish no favours, but despite all that the killifish might have the potential to be one of the animal kingdom's key figures. The mummichog, a certain species of killifish found along the Atlantic coast of North America, puts other species to shame when it comes to adapting to a changing environment. What researchers have found is that the mummichog has has the ability to tolerate highly variable salinity - the amount of salt in the water - and also temperature fluctuations in its habitat.

The fish uses a phenomenon known as phenotypic plasticity. Put simply: The ability of a certain species to change characteristics in response to changes in the environment - and quickly, in the best-case scenario. To deal with different levels of salinity, the killifish activates or deactivates channels that secrete salt. This means the fish is able to change the mechanisms involved in salt balance and thereby live in both salt and freshwater environments.

A recent study - published in the journal of Molecular Biology and Evolution - described the fish's unusually accurate control of genes responsible for the ability to shift between the different water conditions. The small fish is able to change its gills - the part responsible for secreting salt - fast and effectively whenever it’s needed, Joe Shaw, one of the new study's authors explained to Nature World News: "They have to be able to make those changes very rapidly, and to do that it physically changes the structure of its gills."

It’s the scientist’s hope that the fish's abilities mean it might be able to handle other environmental changes as well, including those caused by climate change.
"The spin on climate change is the idea that we're understanding some basic mechanisms of how this ability to change phenotype on a dime has evolved," Nature World News quotes Shaw as saying. And there’s something else that fuels the hope - the mummichog can tolerate temperature fluctuations from 6-degrees Celsius to 35-degrees Celsius a hardiness that might become handy for the fish in the future.