Jan 15, 2022 - Science

"Nothing but fish nests": Massive icefish colony found in Antarctica

Icefish in the Weddell Sea. Photo: Alfred Wegener Institute / PS124 AWI OFOBS team

Scientists have discovered a massive breeding colony of icefish in Antarctica's southern Weddell Sea.

The big picture: Groups of up to 60 icefish nests have been spotted before, but researchers have now found an estimated 60 million active nests, which is believed to be the largest ever seen.

Details: Scientists were towing a camera behind their research vessel early last year to survey the seafloor when they made the surprising discovery.

  • "We found fish nest after fish nest for four hours," says Autun Purser, a deep-sea ecologist at the Alfred Wegener Institute in Bremerhaven, Germany. "Nothing but fish nests."
  • The colony spans an estimated 240 square kilometers (about 93 square miles), the researchers reported in the journal Current Biology.
  • The majority of the nests had one male icefish guarding the eggs.

Why it matters: The researchers think the icefish (Neopagetopsis ionah) could be using the warmer waters in the area to navigate to the breeding colony.

  • Purser says it is likely the icefish are an important food source for Weddell seals that populate the sea ice and are known to dive in the area.

What's next: The scientists left cameras in the water to photograph the nests four times each day for the next three years.

  • They're interested in capturing more details about the nests — including whether the eggs hatch at the same time and if the location of the nests changes — to understand how the massive colony delivers nutrients to the unique ecosystem.
  • "The deep sea and under ice environment are not barren of life," Purser says. The colony is "a huge hidden ecosystem and it must support and influence neighboring ecosystems."

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