In a recent study published in current biology, a collaboration between researchers from the University of Oxford, the University of Lisbon and the British Geological Survey found that the browed albatross is diving deeper than previously realized.
Mollymawks (small to medium-sized albatross such as the browed albatross) are known to dive shallowly, reaching a maximum diving depth of 6 to 9 meters. Data collected by the team revealed that 50% of the birds dived deeper than 10 meters and that dives could be as deep as 19 meters – more than twice the depth previously thought.
GPS devices, depth recorders and accelerometers documented the journeys of the New Island people in the Falklands, commuting to the South American coast and diving at unexpected depths to chase prey.
dr. Oliver Padget, Junior Research Fellow, Department of Zoology at the University of Oxford said:
“A better understanding of the unobserved behavior of the albatross and other endangered seabirds is essential to conservation efforts.
“That browed albatross is physically capable of making such deep dives should now be considered when considering the effectiveness of mitigation strategies that rely on confinement of the species to the surface.”
Diving activities recorded among the population occurred during the day, suggesting that the albatross rely on their vision to hunt deeper-diving prey.
“We found that deep diving was limited to daylight hours, so one potential solution could be to establish pelagic longlines at night, when the albatross is less likely or able to chase carrion and get caught.” dr. Padget continued.
The albatross, the carrier of sailors’ souls, faces a conservation crisis. The sharply declining populations of recent decades have kept albatross among the world’s most endangered species. 15 of the 22 species in the albatross family are in danger of extinction.
A major factor in the decline is modern commercial fishing methods. Seabirds are occasionally caught by vessels targeting large marine fish, such as tuna, with pelagic longlines.
Generally observed as surface feeders, with a powerful sense of smell and shallow diving ability, hungry albatrosses are at particular risk when lines are being set and the baited hooks are still close to the surface.
Measures to reduce bycatch can reduce potential hazards by limiting the availability of hooks to birds if lines sink from the surface (using weights to sink lines faster or Hookpods covering the barb).
These techniques focus on the danger of lines on the surface, because albatross is not [usually] documented diving at depths where the hooks are used for the target catch.
Tim Guilford, Professor of Animal Behaviour, Department of Zoology at the University of Oxford, said: “Diving in this population could be the result of previously unseen behavioral flexibility and have important implications for how we think about the risks to endangered species, and for how they might respond to change.”
Device can save seabirds from the dangers of fishing gear
Tim Guilford et al, Unexpectedly deep diving into an albatross, current biology (2022). DOI: 10.116/j.cub.2021.11.036
Provided by the University of Oxford
Quote: Researchers discover unexpected deep diving in albatross (2022, Jan 20) retrieved Jan 20, 2022 from https://phys.org/news/2022-01-unexpected-deep-albatross.html
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