Blenny fish are trading in water for land – and evolving right before our eyes in order to escape formidable aquatic predators.
More than thirty other species of fish have undergone this same transformation throughout the last 400 million years. Evolution occurs due to a multitude of factors including habitat pressure, lack of food, and commonly to escape predators.
Blenny fish are small inhabitants of the South Pacific Ocean, subject to a number of larger predators including flounder and lionfish. Ecologist Terry Ord and a team out of the University of South Wales have been studying blenny fish persisting around the area of Rarotonga within the Cook Islands in particular.
Researchers have discovered ‘blennies’ inhabiting shallow pools of water around the island during low tide and a fascinating transformation to terrestrial residence higher up on land amongst the rocks when the tide rolls in.
The team presumed the predatory influence was the driving factor and performed an unusual experiment to confirm their theory. They made models of blenny fish and dropped them into the water at high tide. When retrieved, the fake blennies were riddled in puncture marks and wounds, attributing to a proven increase of predatory danger.
The progression to land has additional perks for the blennies, including an endless supply of food provided by algae and bacteria-covered rocks as well as holes in the rocks to serve as safe havens for egg-laying purposes.
“If you never look over the fence, you’ll never know that the grass is greener,” Dr. Ord said in a statement. “However, if you’re forced to the other side to escape something, you may then realise it has additional benefits and want to stay there and adapt.”
The complete findings are published in the American Naturalist.
Watch these amazing fish leap about in a video narrated by Sir David Attenborough below:
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