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Scientists investigating the ocean floor in Antarctica have discovered a southern icefish colony with 60 million active nests.
The discovery, published this Thursday, estimates that the colony covers about 240 square kilometers and contains a fish biomass value of more than 60,000 tonnes, the press release points out.
Our most important finding is the sheer existence of such an extensive colony of southern icefish,” explained Autun Purser, one of the researchers responsible for the discovery. “A dozen nests had been observed elsewhere in the Arctic, but this finding is many orders of magnitude larger.”
Autun Purser, from the Alfred Wegener Institute, in Almenha, carried out, together with the rest of the team, the discovery using equipment that allows observing the ocean floor. “Basically it’s a large towing piece of equipment, which weighs a ton, that we tow behind the icebreaker RV Polarstern at a speed of one to four kilometers per hour”, explained the scientist.
Routine investigation focused on that part of the seafloor because in that region, the water is two degrees Celsius warmer. According to Autun Purser, however, the researchers did not expect to find “any species of fish ecosystem”.
Most of the analyzed nests were occupied by a single adult fish, which guarded more than 1700 eggs. In addition, scientists found several fish carcasses in the nesting area, which suggests that these animals are part of the region’s food chain. Purser and his colleagues suspect that the colony is a feeding place for various predators, such as seals.
The recorded data show that the seals do in fact dive to the depths where the fish nests are, so they could be feeding on them”, he concluded.
This new discovery, published in the journal Current Biology, has revealed a unique ecosystem that could help establish a regional Marine Protected Area in the southwestern Atlantic Ocean.