Story at a glance
- A new study estimates about 60 million icefish nests are grouped together in the Antarctic Weddell Sea.
- The colony covers some 92 square miles.
- Researchers have deployed camera systems to monitor the colony until a research vessel returns to the region later this year to study the vast breeding ground.
A massive fish colony found below the ice covering Antarctica’s Weddell Sea is the largest known breeding ground of fish ever discovered, according to new research published in the journal Current Biology.
In February 2021, the German research vessel Polarstern was surveying the seafloor using a towed camera system that reaches more than 1,000 feet below the sea’s surface, and transmits images up to the deck to be viewed by researchers onboard.
What scientists viewed on the ship’s monitors was an unexpected find: a huge number of icefish nests that appeared to go on forever in all directions.
“The idea that such a huge breeding area of icefish in the Weddell Sea was previously undiscovered is totally fascinating,” Autun Purser, a deep-sea biologist at the Wegener Institute, Helholtz Center for Polar and Marine Research and lead author of the study, said in a statement.
“After the spectacular discovery of the many fish nests, we thought about a strategy on board to find out how large the breeding area was — there was literally no end in sight,” Purser added.
The camera recorded more than 16,000 nests during a four-hour dive. Researchers said mapping of the area suggests the total number of fish nests is about 60 million stretched across 92 square miles of seabed, which would make it the largest such breeding colony ever discovered.
Researchers viewed round fish nests on the seafloor about every 10 inches that measured about 6 inches deep and 29 inches in diameter. Several types of nests were observed, including active nests that contained 1,500 to 2,500 eggs guarded by adult icefish, nests that contained only eggs and empty nests. The nests were carved into the mud by notothenioid icefish.
Camera systems have been deployed to monitor the colony until a research vessel returns to the region later this year to study the vast breeding ground.
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