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Vultures of the seas: hyperacidic stomachs in wandering albatrosses as an adaptation to dispersed food resources, including fishery wastes.

Grémillet D, Prudor A, le Maho Y, Weimerskirch H - PLoS ONE (2012)

Bottom Line: These revealed surprisingly low pH levels (average 1.50±0.13), markedly lower than in other seabirds, and comparable to those of vultures feeding on carrion.Such low stomach pH gives wandering albatrosses a strategic advantage since it allows them a rapid chemical breakdown of ingested food and therefore a rapid digestion.This is useful for feeding on patchy, natural prey, but also on fishery wastes, which might be an important additional food resource for wandering albatrosses.

View Article: PubMed Central - PubMed

Affiliation: CEFE-CNRS, UMR5175, Montpellier, France. david.gremillet@cefe.cnrs.fr

ABSTRACT
Animals are primarily limited by their capacity to acquire food, yet digestive performance also conditions energy acquisition, and ultimately fitness. Optimal foraging theory predicts that organisms feeding on patchy resources should maximize their food loads within each patch, and should digest these loads quickly to minimize travelling costs between food patches. We tested the prediction of high digestive performance in wandering albatrosses, which can ingest prey of up to 3 kg, and feed on highly dispersed food resources across the southern ocean. GPS-tracking of 40 wandering albatrosses from the Crozet archipelago during the incubation phase confirmed foraging movements of between 475-4705 km, which give birds access to a variety of prey, including fishery wastes. Moreover, using miniaturized, autonomous data recorders placed in the stomach of three birds, we performed the first-ever measurements of gastric pH and temperature in procellariformes. These revealed surprisingly low pH levels (average 1.50±0.13), markedly lower than in other seabirds, and comparable to those of vultures feeding on carrion. Such low stomach pH gives wandering albatrosses a strategic advantage since it allows them a rapid chemical breakdown of ingested food and therefore a rapid digestion. This is useful for feeding on patchy, natural prey, but also on fishery wastes, which might be an important additional food resource for wandering albatrosses.

Show MeSH
Parallel recordings of stomach temperature (upper trace, right scale) and stomach pH (lower trace, left scale) in a free-ranging wandering albatross during a seven-day foraging trip at sea.
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pone-0037834-g002: Parallel recordings of stomach temperature (upper trace, right scale) and stomach pH (lower trace, left scale) in a free-ranging wandering albatross during a seven-day foraging trip at sea.

Mentions: We therefore analyzed stomach pH and temperature recordings for three birds. In the bird that went out to sea (for a period of 7 days, Fig. 2), basal stomach pH was extremely low (pH 1.35±0.14), occasionally decreasing to pH 0.51. Parallel temperature recordings indicated ingestion of cold prey (Fig. 2), who’s estimated mass was on average 110±280 g. Prey items were occasionally large, up to an estimated 1160 g. After the intake of such large items, stomach pH rose sharply (up to pH 4.88), and re-acidification to baseline levels only occurred within several hours to one day (Fig. 2). The two birds that stayed on the nest and did not feed showed stable, very low stomach pH levels (average pH 1.50±0.13 and 1.65±0.10, respectively). These values are in line with the ground pH level recorded in the bird that went out to sea, and the average baseline pH was therefore pH 1.50±0.13 across all three birds.


Vultures of the seas: hyperacidic stomachs in wandering albatrosses as an adaptation to dispersed food resources, including fishery wastes.

Grémillet D, Prudor A, le Maho Y, Weimerskirch H - PLoS ONE (2012)

Parallel recordings of stomach temperature (upper trace, right scale) and stomach pH (lower trace, left scale) in a free-ranging wandering albatross during a seven-day foraging trip at sea.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368928&req=5

pone-0037834-g002: Parallel recordings of stomach temperature (upper trace, right scale) and stomach pH (lower trace, left scale) in a free-ranging wandering albatross during a seven-day foraging trip at sea.
Mentions: We therefore analyzed stomach pH and temperature recordings for three birds. In the bird that went out to sea (for a period of 7 days, Fig. 2), basal stomach pH was extremely low (pH 1.35±0.14), occasionally decreasing to pH 0.51. Parallel temperature recordings indicated ingestion of cold prey (Fig. 2), who’s estimated mass was on average 110±280 g. Prey items were occasionally large, up to an estimated 1160 g. After the intake of such large items, stomach pH rose sharply (up to pH 4.88), and re-acidification to baseline levels only occurred within several hours to one day (Fig. 2). The two birds that stayed on the nest and did not feed showed stable, very low stomach pH levels (average pH 1.50±0.13 and 1.65±0.10, respectively). These values are in line with the ground pH level recorded in the bird that went out to sea, and the average baseline pH was therefore pH 1.50±0.13 across all three birds.

Bottom Line: These revealed surprisingly low pH levels (average 1.50±0.13), markedly lower than in other seabirds, and comparable to those of vultures feeding on carrion.Such low stomach pH gives wandering albatrosses a strategic advantage since it allows them a rapid chemical breakdown of ingested food and therefore a rapid digestion.This is useful for feeding on patchy, natural prey, but also on fishery wastes, which might be an important additional food resource for wandering albatrosses.

View Article: PubMed Central - PubMed

Affiliation: CEFE-CNRS, UMR5175, Montpellier, France. david.gremillet@cefe.cnrs.fr

ABSTRACT
Animals are primarily limited by their capacity to acquire food, yet digestive performance also conditions energy acquisition, and ultimately fitness. Optimal foraging theory predicts that organisms feeding on patchy resources should maximize their food loads within each patch, and should digest these loads quickly to minimize travelling costs between food patches. We tested the prediction of high digestive performance in wandering albatrosses, which can ingest prey of up to 3 kg, and feed on highly dispersed food resources across the southern ocean. GPS-tracking of 40 wandering albatrosses from the Crozet archipelago during the incubation phase confirmed foraging movements of between 475-4705 km, which give birds access to a variety of prey, including fishery wastes. Moreover, using miniaturized, autonomous data recorders placed in the stomach of three birds, we performed the first-ever measurements of gastric pH and temperature in procellariformes. These revealed surprisingly low pH levels (average 1.50±0.13), markedly lower than in other seabirds, and comparable to those of vultures feeding on carrion. Such low stomach pH gives wandering albatrosses a strategic advantage since it allows them a rapid chemical breakdown of ingested food and therefore a rapid digestion. This is useful for feeding on patchy, natural prey, but also on fishery wastes, which might be an important additional food resource for wandering albatrosses.

Show MeSH