New analysis by scientists from the University of Oxford, British Geological Survey, and Portugal’s Marine and Environmental Sciences Center exhibits that the black-browed albatross (Thalassarche melanophris) can dive to a lot higher depths (19 m, or 62 toes) and for for much longer (52 seconds) than beforehand thought — thrice the maxima beforehand recorded for this species (6 m, or 20 toes, and 15 seconds), and greater than twice the maxima reliably recorded beforehand for any albatross.
The black-browed albatross (Thalassarche melanophris). Image credit score: Uwe Kils / CC BY-SA 3.0.
“Albatrosses (family Diomedeidae) are the iconic aerial wanderers of the oceans, supremely adapted for long-distance dynamic soaring flight,” stated University of Oxford’s Professor Tim Guilford and his colleagues.
“Perhaps because of this they are considered poorly adapted for diving, in contrast to many smaller shearwater and petrel relatives, despite having amphibious eyes, and an a priori mass advantage for oxygen-storage tolerance.”
“Modern biologging studies have largely confirmed this view, casting doubt on earlier observations using capillary tube maximum depth gauges, which may exaggerate depths, and emphasizing albatrosses’ reliance on near-surface feeding.”
“Nevertheless, uncertainty about albatross diving remains an important knowledge gap since bycatch in human fisheries (e.g. birds becoming hooked when diving for longline bait fish) is thought to be driving many population declines in this most threatened group of birds.”
Using miniature digital depth loggers, the researchers documented the journeys of the black-browed albatross inhabitants within the Falklands commuting to the South American coast and diving at sudden depths to pursue prey.
“A better understanding of the unobserved behavior of the albatrosses and other endangered seabirds is essential to conservation efforts,” stated University of Oxford’s Dr. Oliver Padget.
“That black-browed albatrosses are physically capable of such deep dives will now need to be considered when thinking about the effectiveness of mitigation strategies that rely on the species being restricted to the surface.”
Diving actions recorded amongst the inhabitants happened through the day, suggesting that the albatrosses depend on their imaginative and prescient to pursue shoaling prey on deeper dives.
“We found that deep diving was restricted to daylight hours, and so one potential mitigation could be for pelagic long lines to be set at night when albatross might be less likely, or able, to chase baits and become caught,” Dr. Padget stated.
“Diving in this population could be the result of previously unseen behavioral flexibility, and have important consequences for how we think about the risks to threatened species, and for how they might respond to change,” Professor Guilford stated.
The findings seem within the journal Current Biology.
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Tim Guilford et al. 2022. Unexpectedly deep diving in an albatross. Current Biology 32 (1): R26-R28; doi: 10.1016/j.cub.2021.11.036