Marine researchers have, for the first time, documented seasonal migrations of fishes across the deep sea floor – revealing, they say, an important insight that will further scientific understanding of the nature of our planet.
“We’re extremely excited about our findings, which demonstrate a previously unobserved level of dynamism in fishes living on the deep sea floor – potentially mirroring the great migrations that are so well characterized in animal systems on land,” explains Rosanna Milligan, assistant professor at the Halmos College of Oceanography (HCO), part of Nova Southeastern University in Florida.
The study – published this week in the Journal of Animal Ecology – was carried out by HCO in conjunction with the University of Glasgow.
The teams analysed more than seven years of deep-sea photographic data from West Africa – linking seasonal patterns in surface-ocean productivity with observed behavioural patterns of fishes at 1,500m.
“The work really adds to our understanding of movement patterns in deep-sea fishes and suggests reasons for their behaviours,” says Milligan.
“Because we were able to link the abundances of fish observed at the sea floor to satellite-derived estimates of primary productivity, our results suggest that even top-level predators and scavengers in the deep oceans could be affected by changes filtering down from the surface of the ocean.”
Dr. David Bailey, senior lecturer in marine biology at the University of Glasgow adds: “Animal migrations are really important in nature, because when animals move from place to place, they transport energy, carbon and nutrients.
“Long-term projects like this, and the datasets they generate, are vital to understanding ongoing change in the oceans and how they may be impacted in the future.”
The work was underpinned by an international collaboration between industry, academia and government – involving 10 organizations from Angola, the UK and the USA.
It made use of the Deep-ocean Environmental Long-term Observatory System (DELOS), which is made up of observatories sited permanently on the sea floor at 1,400m housing instrumentation modules including oceanographic sensors and cameras.
The modules are periodically recovered for data download and servicing using a remotely operated vehicle (ROV).
To find out more about the DELOS project go to: https://www.delos-project.org