Aggregation Patterns of Pelagic Predators and their Principal Prey, Antarctic Krill, near South Georgia

Veit, Richard R.; Silverman, Emily; Everson, Inigo

doi:10.2307/5204

Cited by 79 publications

(56 citation statements)

References 24 publications

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“…Correlations with prey characteristics were apparent only when the relationship of murres to krill was considered at the scale of an individual krill patch regardless of its horizontal size. Similar results have been observed in examining correlations with other marine predators and their prey (Veit et al 1993, BenoitBird & Au 2003, Benoit-Bird et al 2004, indicating that alternative statistical approaches to gridded analyses or other spatially explicit approaches may be necessary in these systems to identify predator− prey relationships.…”

Section: Murres In Prey Patchessupporting

confidence: 63%

“…The large variety of prey that murres consumed during the study and their ability to switch between one diet for themselves and another for their chicks suggests that to accomplish this, a wide variety of prey types must be quantified, in contrast to most previous seabird− prey studies which have focused on a single prey group (e.g. fish or krill; sensu Ainley et al 1993, Veit et al 1993, Zamon et al 1996, Swartzman & Hunt 2000, Davoren et al 2003, Grünbaum & Veit 2003, but see Kokubun et al 2008). The diving capabilities of foraging murres indicate that the vertical overlap of murres and their prey must also be considered.…”

Section: Introductionmentioning

confidence: 99%

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Active acoustic examination of the diving behavior of murres foraging on patchy prey

Benoit‐Bird¹,

Kuletz²,

Heppell³

et al. 2011

Mar. Ecol. Prog. Ser.

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During the 2008 and 2009 breeding seasons of murres Uria spp., we combined visual observations of these predators with active acoustics (sonar), fish trawls, zooplankton net tows, and hydrographic measurements in the area surrounding breeding colonies in the southeastern Bering Sea. We acoustically detected thousands of bubble trails that were strongly correlated with the number of visually detected murres, providing a new tool for quantitatively studying the foraging ecology of diving birds. At the regional scale, the number of acoustically detected bubble trails, which served as a proxy for diving murre abundance, was related to the combined availability and vertical accessibility of squid, krill, and pollock. There were, however, no clear relationships at this scale between diving murres and any individual prey taxon, highlighting the importance of prey diversity to these animals. Individual krill patches targeted by murres had higher krill density and were located shallower than the mean depth of krill patches, but were similar in total krill abundance and overall size. The diving depth of murres within krill patches was highly correlated to the depth of the upper edge of these patches, whereas murres found outside of krill patches showed a depth distribution similar to that of juvenile pollock. Throughout the study area, murres showed strong diel patterns in their diving behavior in response to the diel migrations of their prey. These results suggest that murres select prey with specific patch characteristics implying effective information gathering about prey by murres. The high proportion of diving murres in aggregations and their consistent inter-individual spacing support the hypothesis that intraspecific local enhancement may facilitate foraging in these predators.

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Section: Murres In Prey Patchessupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Active acoustic examination of the diving behavior of murres foraging on patchy prey

Benoit‐Bird¹,

Kuletz²,

Heppell³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…The entire suite of land-based predator species monitored at Bird Island (macaroni and gentoo penguins, blackbrowed albatrosses and Antarctic fur seals) as part of CEMP are often described as 'krill-dependent predators' (Croxall & Prince 1987, Veit et al 1993, Reid et al 1999a). None of the Bird Island species is an obligate euphausiid feeder (Reid & Arnould 1996, Croxall et al 1997, 1999.…”

Section: Discussionmentioning

confidence: 99%

Diet variability and reproductive performance of macaroni penguins Eudyptes chrysolophus at Bird Island, South Georgia

Waluda¹,

Hill²,

Peat³

et al. 2012

Mar. Ecol. Prog. Ser.

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“…Croxall et al 1984, Croxall & Prince 1987, Trivelpiece et al 1987, or deduced from observations at sea of birds of unknown status and/or origin (e.g. Stahl et al 1985, Hunt et al 1992, Veit et al 1993, Trathan et al 1998. The relatively recent developments in miniaturisation and hydrodynamic design of instruments for satellite tracking has made the characterisation of penguin foraging ranges feasible.…”

Section: Introductionmentioning

confidence: 99%

Seasonal and interannual variation in foraging range and habitat of macaroni penguins Eudyptes chrysolophus at South Georgia

Barlow¹,

Croxall²

2002

Mar. Ecol. Prog. Ser.

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In marine ecosystems, characterisation of the foraging areas and habitats of predators is a key factor in interpreting their ecological role. We studied the foraging areas of the macaroni penguin Eudyptes chrysolophus at Bird Island, South Georgia, throughout the breeding seasons of 1999 to 2001 using satellite tracking. We investigated differences in foraging ranges and characteristics between different stages of the breeding season, between sexes, between years and between individuals. During incubation, on foraging trips of 10 to 26 d, both sexes travelled long distances from Bird Island (male average = 572 km; female average = 376 km) in a north-westerly direction towards the Maurice Ewing bank; some individuals, particularly males, travelled to forage in the Polar Frontal Zone. In contrast, during the chick-rearing period, both sexes mainly foraged relatively close (average 62 km) to South Georgia over the continental shelf. Foraging trip characteristics differed between males and females during chick rearing: females travelled further on average and on more direct trips. During chick rearing, males and females on longer foraging trips covered greater distances and travelled further from Bird Island. There were no interannual differences in characteristics of foraging trips, although sex differences in some parameters varied between years. The bearings of chick-rearing foraging trips were non-random and most were in a north-westerly direction. Variation, both intra-and inter-individual, in bearings of foraging trips was high. Travel speeds were slower during foraging trips in the chick-rearing period than during incubation, probably relating to the differences in distances travelled. The stage of the breeding season, associated constraints on the penguins at different stages, and sex were important in determining variation in foraging range and characteristics in macaroni penguins, but year and individual effects were relatively unimportant.

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Aggregation Patterns of Pelagic Predators and their Principal Prey, Antarctic Krill, near South Georgia

Cited by 79 publications

References 24 publications

Active acoustic examination of the diving behavior of murres foraging on patchy prey

Active acoustic examination of the diving behavior of murres foraging on patchy prey

Diet variability and reproductive performance of macaroni penguins Eudyptes chrysolophus at Bird Island, South Georgia

Seasonal and interannual variation in foraging range and habitat of macaroni penguins Eudyptes chrysolophus at South Georgia

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