A team of scientists has identified the world’s largest fish spawning habitat near the Filchner Ice Shelf in the south of the Antarctic Weddell Sea using a towed camera system. They photographed and videotaped many Neopagetopsis icefish nests.
The observations are made with an OFOBS, or Ocean Floor Observation and Bathymetry System, a camera system designed to examine the bottom of severe settings such as ice-covered oceans. The camera was towed by scientists on a customized fiber-optic and power line at a speed of roughly half a knot, around one and a half meters above the seafloor.
While monitoring the seafloor with this camera system in February 2021, the team aboard the research vessel Polarstern discovered the mind-bogglingly large icefish breeding colony.
The photographs revealed a plethora of fish nests. Further investigation reveals that the researchers found a maximum of one to two active nests per square meter, with an average of one breeding site every three square meters.
The researchers estimated the overall number of fish nests to be around 60 million. The nests are 75 centimeters in diameter and 15 centimeters deep.
“The concept that such a large breeding area of icefish in the Weddell Sea was previously undetected is exciting,” said Autun Purser, a deep-sea biologist at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) and lead author of the current study.
“After the stunning finding of the many fish nests, we discussed a strategy on board to determine the size of the breeding region – there was no end in sight.” The nests are three-quarters of a meter in diameter – far more significant than the structures and creatures, some of which are barely millimeters in size, that the OFOBS system routinely detects.”