Deep dives are a thing of the past! Albatrosses can plunge up to 62ft underwater to pursue prey—more than twice as deep as previously thought, study reveals
- University of Oxford-led experts studied the dives of black-browed albatrosses
- They focussed on those populations that live on New Island, in the Falklands
- Past studies had shown that medium-sized albatrosses only dove to 20–30 feet
- The researchers found that over half of birds can dive to 33 feet.
- This information could be used to help protect birds from longline fishing
Black-browed albatrosses can plunge up to a whopping 62 feet (19 metres) into the sea in pursuit of their prey — more than twice the depth previously thought.
Experts from the University of Oxford came to this conclusion after using GPS and accelerometers to analyze the population of New Island in the Falklands.
They monitored the birds as they commuted to the South American coast.
Past studies had indicated that mollymawks — the name given to such medium-sized albatrosses — only dive shallowly, to a maximum of around 20–30 feet (6–9 m).
However, the team found that half of the black-browed albatrosses studied could dive deeper than 33 feet (10 m) — with some reaching nearly twice this depth.
Black-browed albatrosses (pictured) can plunge up to a whopping 62 feet (19 metres) into the sea in pursuit of their prey — more than twice the depth previously thought
The study was undertaken by zoologist Oliver Padget of the University of Oxford and his colleagues at the University of Lisbon and the British Geological Survey.
‘A better understanding of the unobserved behaviour of the albatross and other endangered seabirds is essential to conservation efforts,’ said Dr Padget.
The researchers found that fifteen of 22 species albatross were at imminent risk of extinction. Their populations have declined over the past decade.
The main reason for their decline was how these seabirds could end up being caught in hooked-baited fishing longlines that are used to catch large ocean-going fish, such as tuna.
With albatrosses having been considered as surface feeders only — sporting a powerful sense of smell and only a shallow diving ability — traditional approaches to protect the birds have focussed on protecting the birds as the lines are initially sunk.
For example, some fishers use weights to ensure their lines drop to the target depth faster — or use so-called hookpods that cover the barbs on the lines.
When considering mitigation strategies for the species that require them to stay at the surface, it will be important to remember the fact that the black-browed albatross is physically capable of deep diving.
The team also noted that the black-browed albatrosses did not dive at night — suggesting that the birds rely on their vision to pursue shoals of fish at depth.
Dr Padget added, “We discovered that deep diving is limited to daylight hours.”
“Hence, one possible mitigation would be for long pelagic lines to be laid at night when albatross is less likely to chase down baits or become captured.”
The team found that half of the black-browed albatrosses studied could dive deeper than 33 feet — with some reaching nearly twice this depth. Photographed are two birds from New Island
‘Diving in this population could be the result of previously unseen behavioural flexibility,’ said paper author and animal behaviour expert Tim Guilford of the University of Oxford.
He said that the results could have ‘important consequences for the way we think about threats to species and the ways they might respond to changes’
All findings were published in Current Biology.
University of Oxford-led experts used GPS sensors, accelerometers and depth recorders to study the population of black-browed albatrosses living on New Island, in the Falklands
Advertisement