In the ice-covered Weddell Sea off the coast of Antarctica, a remarkable discovery was made. It is a unique and previously unknown ecosystem – a breeding colony with up to 60 million fish. Such a spectacular phenomenon proves how little we know about the ocean depths.
Scientists at the Alfred Wegener Institute in Bremerhaven monitored the seabed about 500 meters below the vessel they were aboard. The scientists’ mission was to study ocean currents. Fish nests were discovered by accident. One night, while most of the Polarstern crew was asleep, the cameras caught something unexpected. Another fish nest appeared on the screen every 20 seconds. The longer the observation lasted, the more excited the scientists grew. No wonder. Checking the entire surface revealed that the nesting area is about 250 square kilometers. It’s about as much as Malta territory. Therefore, it has been estimated that the total number of fish nests is around 60 million. Each of them was about 15 centimeters deep and had an average of 1,735 eggs. Most of them were watched over by one adult fish. Some of the nests only contained eggs, some were empty.
Given the biomass of fish, this large breeding area is an extremely important part of the Weddell Sea ecosystem and is arguably the largest known area of this type in the world, the researchers wrote in Current Biology. According to the researchers, the discovery confirms the validity of the efforts to create a protected area in the South Atlantic Ocean.