New research has finally demonstrated what many marine biologists suspected, but had never before seen: fish migrating through the deep sea.
The study, published last month in the Journal of Animal Ecology, used analysis of deep-sea photographs to show a regular increase in the number of fish in particular months, suggesting seasonal migrations.
Tracking fish in the deep sea is challenging. They are sparsely distributed, the water is nearly devoid of sunlight and the monitoring equipment has to withstand enormous pressure.
The study used photographs taken by the Deep-ocean Environmental Long-term Observatory System (DELOS), two observatories on the sea bed, 1,400m below the surface, off the coast of Angola.
The researchers analyzed 12,703 photographs — only 502 of which had actually managed to capture a fish — taken over seven-and-a-half years, and found that each year, in late November and June, there was a spike in the number of fish.
“It is certainly not unprecedented, but it has never really been demonstrated,” said Rosanna Milligan, an assistant professor at Nova Southeastern University in Florida and the lead author on the paper. “That is what we were able to do with this study.”
“Even after all these years, one of my favorite parts of being a scientist is when you do those first graphs of your results and start to see something emerging from the data,” said David Bailey, a senior lecturer at the University of Glasgow and a coauthor on the paper.
“That’s one of the greatest thrills of the whole scientific endeavor. It was really, really amazing,” he said.
Even with this new discovery, Milligan and Bailey still say there is a lot they do not know.
“The natural thing to do is to find out where the fish are coming from and going to when they move around,” Bailey said. “What is going on? What does it mean and what are the fish doing?”
Little is known about the behavior of any of the fish photographed.
Grenadiers, a family of fish seen in more than 100 of the DELOS photos, have long tails that might allow them to move great distances at low speed — but despite being a relatively common deep-sea fish, little information exists on how far they can swim.
A 1992 paper, for instance, put acoustic tracking devices in bait and fed them to grenadiers, but the devices only tracked the fish up to 1km away.
Milligan said the fish might be migrating to follow dying organisms on the surface.
Plankton blooms off the coast of West Africa every year four months before the deep-sea fish migrate into the area.
Given that the deep sea is dependent on life at the surface that dies and sinks to the bottom, it is possible that other animals could be gathering to take advantage of the dying plankton, and the deep-sea fish migrate to eat those.
“We just have no idea how these things act,” said Tim O’Hara, a researcher and senior curator of marine zoology at Museums Victoria in Australia, who was not involved in the research. “We are literally groping in the dark. It’s kilometers down in the ocean and we get these tiny bits of information from one or two locations and we’re trying to put together a big picture.”
Milligan and Bailey said they hope this discovery encourages other researchers to look for similar patterns in the deep oceans.
“Maybe if we had more of this level of surveillance in other places, we would find fish migrations in all kinds of places,” Bailey said. “It’s just that [Angola] is where we happened to be observing in this level of detail for this amount of time? This could be happening all over the place.”
‘OBVIOUS DIFFERENCE’: The Wuhan Institute of Virology has been researching bat coronaviruses to trace the SARS pathogen, which is 80 percent similar to SARS-CoV-2 The Chinese virology institute in the city where COVID-19 first emerged has three live strains of bat coronavirus on-site, but none match the new contagion wreaking havoc around the world, its director has said. Scientists think COVID-19 — which first emerged in Wuhan and has killed more than 340,000 people worldwide — originated in bats and could have been transmitted to people via another mammal. However, the director of the Wuhan Institute of Virology told state broadcaster China Global Television Network that claims made by US President Donald Trump and others that the novel coronavirus could have escaped from the facility were
SPACE RACE: The China Aerospace Science and Technology Corp mission aims to land a robotic rover and put a probe into orbit around the planet China is targeting a July launch for its ambitious Mars mission, which includes landing a remote-controlled robot on the surface of the Red Planet, the company in charge of the project has said. Beijing has invested billions of dollars in its space program in an effort to catch up with its rival, the US, and affirm its status as a major world power. The Mars mission is among a number of new space projects China is pursuing, including putting Chinese astronauts on the moon and having a space station by 2022. Beijing had been planning the Mars mission for some time this year,
India has moved additional troops along its northern border as it prepares for an extended conflict with China, after several rounds of talks failed to ease tensions between the nuclear-armed rivals. China has already placed about 5,000 soldiers and armored vehicles within its side of the disputed border in the Ladakh region, an Indian government official said, asking not to be identified, citing rules. India is adding a similar number of troops as well as artillery guns along the border to fend off the continuing incursions by the Chinese army, the official said. The standoff began on May 5, when troops clashed
China is poised to enshrine individuals’ rights to privacy and personal data for the first time, a symbolic first step as more of the country of 1.4 billion people becomes digitized — and more vulnerable to leaks and hacks. The legislation is part of China’s first civil code, a sweeping package of laws that is being deliberated during the annual meeting of China’s National People’s Congress, which began on Friday after a delay of more than two months due to the COVID-19 pandemic. According to a recent draft, an individual has a right to privacy and to have their personal information protected. Data
RSS