A team of oceanographers from the University of Hawaii at Manoa (UH, USA), the Monterey Bay Aquarium Research Institute (MBARI, USA) and the National Center for Oceanography (NOC, UK ) has discovered the largest number of fish ever seen in the abyssal region of the deep sea that lies between 3,000-6,000 meters below the ocean surface.
When we are at high altitudes, where only the hardiest plants and animals can live, we see very few of them, precisely because temperatures are colder and life becomes increasingly scarce . The same thing happens at great depths. Or so we thought.
“Our observations really surprised us ,” said Astrid Leitner, lead author of the study, who conducted this work as a graduate researcher at UH Manoa’s School of Ocean and Land Science and Technology (SOEST). “We have never seen reports of such high numbers of fish in the sparsely populated and food-starved deep sea.”
This is the Clarion Clipperton Zone (CCZ), a large region that stretches almost from Hawaii to Mexico, where abyssal seamounts lie 3,000 meters below the surface, dotting the deep seascape. They are among the least explored areas on the planet due to their complexity to visit.
Well, at the top of one of those completely unexplored seamounts they found a swarm of 115 killer eels ( Synaphobranchidae Family) in a small bait pack that contained about 1 kg of mackerel. They caught some eels in a baited trap and were identified as Ilyophis arx , a little-known species with fewer than 10 specimens in fish collections around the world.
They found more eels on top of all the seamounts in the area.
“If this phenomenon is not limited to these two seamounts in the CCZ, the implications for deep sea ecology could be widespread, ” Leitner said. “Our findings highlight how much is yet to be discovered in the deep sea and how much we could all lose if we don’t manage mining properly.”
Referencia: Astrid B. Leitner, Jennifer M. Durden, Craig R. Smith, Eric D. Klingberg, Jeffrey C. Drazen. Synaphobranchid eel swarms on abyssal seamounts: Largest aggregation of fishes ever observed at abyssal depths. Deep Sea Research Part I: Oceanographic Research Papers, 2020; 103423 DOI: 10.1016/j.dsr.2020.103423
