Friday, January 14, 2022

Colony of 60 million fish discovered in Antarctica

 


The vast colony, believed to be the world's largest, is home to the remarkable icefish (Neopagetopsis ionah), which has a see-through skull and transparent blood. It's the only vertebrate to have no red blood cells.


To survive at such low temperatures, it has evolved an anti-freeze protein in its transparent blood that stops ice crystals from growing.


The breeding colony was discovered in February 2021 by the German polar research vessel Polarstern, which was surveying the seabed about half a kilometer below the ship. It used a car-sized camera system attached to the stern of the ship that transmits pictures up to the deck as it's being towed.


The expedition was focused on ocean currents and the discovery of the nests, made distinct from the muddy seabed by a circle of stones, was a surprise.


"We just saw fish nest after fish nest for the whole four hours, and during that time we covered maybe six kilometers (3.7 miles) of the sea floor," said Autun Purser, a postdoctoral reseacher at the Alfred Wegener Institute in Bremerhaven, Germany. He's the lead author of a study on the icefish colony that published in the journal Current Biology on Thursday.


The colony covers more than 240 square kilometers (93 square miles), the researchers said. With, on average, one nest for every three-square meter, they estimated that the colony includes about 60 million active nests.


Each of the evenly spaced nests was about 15 centimeters (6 inches) deep and 75 centimeters in diameter, contained on average 1,735 eggs. Most were guarded by one adult fish. Some nests only contained eggs, and some were unused.

No comments:

Post a Comment

Follow