When it comes to cool customers, it doesn’t get much cooler than this: variegated snailfish, small fish that live off the coast of Greenland, have the largest amount of antifreeze proteins in their bodies ever measured, researchers at the American Museum of Natural History and the City University of New York (CUNY) have found.
However, this specialist adaptation may put them at risk of survival as water temperatures rise due to climate change, the researchers say.
As fish are unable to survive any amount of freezing in their bodies – unlike several species of reptiles such as garter snakes – some species living in the Arctic have evolved the ability to produce antifreeze proteins in their livers that help to prevent ice crystals forming inside their cells and causing them harm.
When investigating the genome of snailfish, or Liparis gibbus, to study their unusual bioluminescent properties, the team noticed that the fish have two different types of gene families involved in the encoding of antifreeze proteins – the highest levels ever observed.
“Similar to how antifreeze in your car keeps the water in your radiator from freezing in cold temperatures, some animals have evolved amazing machinery that prevent them from freezing, such as antifreeze proteins, which prevent ice crystals from forming,” said Prof David Gruber, a research associate at the American Museum of Natural History.
“We already knew that this tiny snailfish, which lives in extremely cold waters, produced antifreeze proteins, but we didn’t realize just how chock-full of those proteins it is—and the amount of effort it was putting into making these proteins.”
However, this adaptation may prove to be the snailfish’s eventual undoing. Thanks to ocean temperatures around the world rising, some predictions estimate that the Arctic Ocean may be mostly ice-free within the next three decades. This could lead to the snailfish being outcompeted by other species moving into their patch, the researchers say.
“Arctic seas do not support a high diversity of fish species, and our study hypothesises that with increasingly warming oceanic temperatures, ice-dwelling specialists such as this snailfish may encounter increased competition by more temperate species that were previously unable to survive at these higher northern latitudes,” said Prof John Sparks, a curator in the Museum’s Department of Ichthyology
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