Foraging ecology of Antarctic seabirds in the Scotia Sea.
Item
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Title
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Foraging ecology of Antarctic seabirds in the Scotia Sea.
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Identifier
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AAI3288749
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identifier
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3288749
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Creator
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Santora, Jarrod A.
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Contributor
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Adviser: Richard R. Veit
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Date
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2007
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Ecology | Biology, Oceanography | Biology, Zoology
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Abstract
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I studied the foraging behavior of seabirds near the western Antarctic Peninsula. The central questions in this study are: Where do seabirds forage? and How do they respond to prey distribution? I use a combination of field surveys and analytical techniques to examine the response of Cape Petrels (Daption capense) and Chinstrap Penguins (Pygoscelis antarctica) to changes in krill distribution (Euphausia superba). First, I present a study of satellite-tracking and ship-based survey for measuring the foraging distribution of penguins. I demonstrate that foraging distributions of penguins, measured by these two methods, are quite different. All satellite-tracked penguins foraged in a core area, whereas foraging penguins counted from ship were greater to the east and west of the core area. Penguins counted from ship were correlated with dense krill patches that were located 10-15 km from breeding colonies. Second, I investigate whether seabirds prefer to forage in locations on the basis of krill patchiness. Penguins prefer to forage in areas where krill are patchy at scales ranging from 1 to 5 km, whereas petrels preferred areas where krill was patchy at one particular scale (e.g. 1 or 5 km). Third, I establish a system for monitoring the association of foraging seabirds and krill near the Antarctic Peninsula. Over three years (2004-2006), I found that abundance of krill varied by more than 2 orders of magnitude, and there is a negative relationship between abundance and patchiness of krill. Penguins were only associated with krill when patchiness of krill was low (2004). Petrels were associated with krill when patchiness of krill was either high (2006) or low, but not at intermediate levels (2005). Fourth, I present a study on how changes in krill distribution, within a few days, affects seabird foraging distribution. After a gale, I found that krill abundance decreased by 50% and horizontal distribution of krill shifted between two hydrographic canyons. Foraging distribution of petrels were linked to changes in krill distribution, but penguins were not.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
