Antarctic icefish colony with 60 million nests discovered

Scientists have discovered what is believed to be the largest known breeding colony of fish on the planet, hidden beneath the ice of Antarctica's Weddell Sea. The colony, consisting of an estimated 60 million active nests of the Jonah's icefish (Neopagetopsis ionah), was found near the Filchner Ice Shelf at depths of 420 to 535 meters Source: Gizmodo. The discovery was made during a 2021 expedition aboard the German research vessel Polarstern, using a towed camera system called OFOBS Source: elconfidencial.

The discovery

The cameras captured images of circular nests, each about 75 centimeters in diameter and 15 centimeters deep, containing between 1,500 and 2,500 eggs. In three out of four active nests, an adult fish was guarding the eggs Source: Gizmodo. The surveyed area covered 45,600 square meters, directly counting 16,160 nests, while sonar detected over 100,000 additional structures. Extrapolating from the density, researchers estimate the colony spans approximately 240 square kilometers, comparable to the size of Malta Source: elconfidencial.

Ecological significance

The colony's biomass is estimated at 60,000 tons, making it a crucial part of the Antarctic ecosystem. The area coincides with an inflow of relatively warmer deep water, which may create favorable conditions for such a dense aggregation Source: Gizmodo. Notably, Weddell seals equipped with transmitters were found to dive within the breeding area 90% of the time, likely attracted by the abundant food source Source: elconfidencial.

Conservation implications

Researchers argue the discovery strengthens the case for establishing a marine protected area in the Weddell Sea, where fishing would be restricted and only non-invasive research allowed Source: elconfidencial. The study was published in the journal Current Biology Source: elconfidencial.