Zoology. so far, Neopagetopsis ionah lived away from the public square. Even the Anglo-Saxons, with their consummate art of finding an appealing name for every species, had not made “Jonah’s icefish” a star of zoology. Offense of dirty mouth, will say some. Blame the depths of Antarctica, not the most accessible, will argue others.
Its colorless blood – because it lacks hemoglobin, but is filled with antifreeze factors enabling it to resist the negative temperatures at the interface between water and sea ice – could have earned it the trumpets of fame. Or this habit of keeping watch over its nest. But about twenty other cousin species of the “crocodile fish” family (Channichthyidae) displayed as many. There remained a few anatomical peculiarities, dear to systematists, and a curved spine on the muzzle. Not enough to make a popular song.
The article published Thursday, January 13 in the journal Current Biology could make it change category. During an expedition in the Weddell Sea – an area covered with ice, at the edge of the pack ice, best known for its colonies of emperor penguins – a team from the Alfred Wegener Institute for Polar and Marine Research, whose headquarters in Bremerhaven (Germany), discovered the largest spawning ground ever unearthed. Photos fixed 16,000 nests, video image analysis listed more than 100,000, and sonar recordings spotted one million. And again: by extrapolating their sampling to the 240 square kilometers of the presumed spawning area, the scientists retain the astronomical figure of 60 million nests, placed on the bottom, at a depth of 435 to 520 meters.
The four discoverers did not expect such a party in February 2021. The expedition and its fifty crew members first had to study the transport of carbon from the frozen surface to the bottom of the seas. Then list the different living, animal and plant communities. With stops and access to limited instruments. In the area in question, Autun Purser and his three colleagues in charge of photographing the seabed had six hours to immortalize them. “We were amazed, admits the biologist. Until now, we had mainly described isolated nests for this species, and rare cases gathering up to a few dozen. »
Considerable biomass
The structures have a remarkable regularity: circular, with a diameter of about 70 centimeters and a depth of 15 centimeters. To make them, the fish, about 50 centimeters in length, swims in a circle, sweeps away the light sediments, leaving behind the pebbles deposited by the melting of the pack ice. “The currents are weak in this area, so the structures remain stable”, emphasizes Autun Purser.
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