Under Antarctic ice, the largest group of nesting fish has been discovered

This surprising discovery is much larger than other known fish nest collections. Image of Jonah’s three ice fish surrounding two circular nests Channichthyidae (Neopagetopsis Yonah) lay more than 1,000 eggs…

This surprising discovery is much larger than other known fish nest collections.

Image of Jonah’s three ice fish surrounding two circular nests
Channichthyidae (Neopagetopsis Yonah) lay more than 1,000 eggs in a circular nest with a hard rock center – Alfred Wegner College, PS124 OFOBS Team

According to a new study, 500 meters below the ice that covers the Weddell Sea in Antarctica is a known population of the world’s largest breeding fish.

Channichthyidae is estimated to have 60 million active nests covering at least 240 square kilometers, about the same size as Orlando, Florida. Many species of the fish nest, from freshwater cichlids to artistically sloping pufferfish (SN: 10/13/20). But so far, researchers have encountered only a handful, or perhaps dozens, of channichthyidae nests at a time. Even the most interesting nesting fish are known to be hundreds of fish.

Researchers report in the January 13th issue of Current Biology.

Autumn Purser, a deep-sea biologist at the Alfred Wegener Institute in Bremerhaven, Germany, and his colleagues encountered a huge colony during a research voyage in the Weddell Sea in the middle of the South Peninsula in early 2021. ..
Researchers are studying the chemical relationship between surface water and the ocean floor. Part of the study involved investigating life on the ocean floor by slowly pulling on the equipment behind a scientist’s icebreaker research vessel. The device took a video as it glide across the ocean floor and used audio to map the features of the ocean floor.

At the Filchner Ice Shelf in the Weddell Sea, one of Parser’s colleagues noticed that he was operating a camera tractor and repeatedly encountered the circular channichthyidae (Neopagetopsisionah) below. Channichthyidae, found only in the Antarctic and Antarctic waters, show strange adaptations to extreme colds, such as clear blood filled with antifreeze (SN: 9/19/98).

“When we came down 30 minutes later and saw the nests one after another for the first four hours of our first dive, we thought we had encountered something strange,” Parser recalls.

Parser and his colleagues surveyed the area three more times and found nests of similar density every kilometer. Among the spawning fish, one of the closest comparisons to icefish could be bluegill (Lepomis macrochirus). However, researchers say the Weddell Sea colonies are orders of magnitude larger, based on measurements showing approximately one icefish nest per 4 square meters over an area of ​​hundreds of kilometers.

Recent audio and video research has revealed that Antarctic fish called channichthyidae gather to lay millions of eggs, forming a circular nesting site that stretches for miles. ..
Alfred Wegner College, PS124 OFOBS Team

Thomas Desvigne, an evolutionary biologist at the University of Oregon at Eugene, who was not involved in the study, said the colony was an “incredible discovery.” He was particularly impressed with the concentration of his hideout.

“It reminds me of a bird’s nest,” Desvines said. “When I see cormorants and other seabirds nesting like this, one by one-almost like that.”

It is unclear why so many channichthyidae gather in one place to lay eggs. This location seems to have easy access to plankton, an important food source for newly hatched fish. The team also found an area of ​​slightly warmer water in the area. This can help icefish find spawning grounds.

Researchers say icefish may be life-sustaining Weddell seals. Previous studies have shown that seals spend a lot of time diving in the ocean above the colony.

Parser suggested that there may be a small herd of channichthyidae near the coast where the ice cover is low. However, Jonah’s icefish relies on a huge spawning school and may effectively store all their eggs in one basket. If so, it would “make the species very vulnerable to extinction,” Desvines said. He said the discovery of this huge colony was yet another reason to provide environmental protection to the Weddell Sea, as it did in the nearby Ross Sea.

The parser currently has two undersea cameras in the colony, staying for several years and taking pictures four times a day to see if the nest will be reused in the long run.

“I think [mega colonies] are almost a new type of marine ecosystem,” Parser said. “Wow, I’ve never seen it before”

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