Foraging by murres (Uria spp.) at tidal fronts surrounding the Pribilof Islands, Alaska, USA

Decker, Mary Beth; Hunt, George L.

doi:10.3354/meps139001

Cited by 93 publications

(67 citation statements)

References 16 publications

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“…This feature, which is evident along the entire southeastern shelf, limits the horizontal flux of salt, nutrients and heat between the middle and coastal domains (Coachman, 1986;Kachel et al, 2002). A similar feature occurs around the Pribilof Islands, where it enhances feeding opportunities for higher trophic level organisms (Kinder, Hunt, Schneider & Schumacher, 1983;Decker & Hunt, 1996;Hunt, Coyle, Hoffman, Decker & Flint, 1996a;Brodeur, Wilson & Ciannelli, 2000).…”

Section: The Eastern Bering Sea Regionmentioning

confidence: 93%

Climate change and the control of energy flow in the southeastern Bering Sea

Hunt

Stabeno

2002

Progress in Oceanography

144

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We examine how coupling between physical and biological processes influences the production and transfer of energy to upper trophic-level species in the southeastern Bering Sea. We review time series that illustrate changes in the marine climate of the southeastern Bering Sea since the mid-1970s, particularly variability in the persistence of sea ice and the timing of its retreat. Time series (1995 -2001) from a biophysical mooring in the middle domain of the southeastern shelf support the hypothesis that retreat of the winter sea ice before mid-March (or the failure of ice to be advected into a region) results in an open water bloom in May or June in relatively warm water (Ն3°C). Conversely, when ice retreat is delayed until mid-March or later, an ice-associated bloom occurs in cold (Յ0°C) water in early spring. These variations are important because the growth and production of zooplankton and the growth and survival of larval and juvenile fish are sensitive to water temperature. The Oscillating Control Hypothesis (OCH) recently proposed by Hunt et al. (2002), predicts that control of the abundance of forage fish, and in the case of walleye pollock (Theragra chalcogramma), recruitment of large piscivorous fish, will switch from bottom-up limitation in extended periods with late ice retreat to top-down in warmer periods when ice retreat occurs before mid-March. In support of this hypothesis, we review recent data from the southeastern Bering Sea that show 2-to 13-fold changes in copepod abundance with changes in spring water temperatures of 3 to 5°C. We also provide indirect evidence that the abundance of adult pollock on the eastern Bering Sea shelf negatively affects the abundance forage fishes (including juvenile pollock) available to top predators. Although there is evidence that pollock year-class strength is positively related to temperature, we lack the time series of pollock populations in extended periods (8 -10 years) of cold-water blooms necessary to test the OCH. 

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Section: The Eastern Bering Sea Regionmentioning

confidence: 93%

Climate change and the control of energy flow in the southeastern Bering Sea

Hunt

Stabeno

2002

Progress in Oceanography

144

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“…The waters surrounding these islands are very productive in terms of prey concentrations due to structural fronts which exist around the 50 m isobath (Kinder et al 1983, Coyle & Cooney 1993, Brodeur et al 1997. However, these fronts are not likely to be a haven from predation since they are the feeding grounds for a large number of land-based piscivorous birds (mainly mur- Springer 1992, Decker & Hunt 1996. Since these birds and mammals are primarily visual predators, the time of greatest juvenile pollock vulnerability is likely to be during the day.…”

Section: 40mentioning

confidence: 99%

In situ observations of the association between juvenile fishes and scyphomedusae in the Bering Sea

Brodeur¹

1998

Mar. Ecol. Prog. Ser.

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In September 1995, dense aggregations of large scyphomedusae (mainly Chrysaora melanaster) were observed in 27 midwater deployments of a remotely operated vehicle (ROV) near the Pribilof Islands in the Bering Sea. Age-0 walleye pollock Theragra chalcogramma appeared to be frequently associated with these gelatinous zooplankton. During daytime, up to 30 pollock were observed swimming within the tentacles of these medusae, but when approached by the ROV, the pollock generally left the vicinity of the jellyfish. At night, few such associations were observed and juvenile pollock moved closer to the surface, apparently feedng in loose aggregations, while the medusae remained close to the thermocline (35-40 m). Prowfish Zaprora silenus were also observed near large medusae, but tended to be found closer to the bell rather than within the tentacles. The lack of any gelatinous material in the stomachs of the pollock suggests that juvenile pollock associate to gain shelter from predation or possibly as a thigmotactic response to biotic structure. The implications of this cornmensal behavior with gelatinous zooplankton are discussed relative to pollock recruitment in the Eastern Bering Sea.

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“…Perhaps food availability on the shelf in 2009 was sufficient to outweigh the additional energetic and time costs associated of commuting to the continental shelf-break/basin, and/or chick provisioning requirements confined day-time foraging trips. Certainly, previous studies have shown that Pribilof murres sometimes forage on the shelf in frontal areas associated with tidal currents and bottom topography (Decker and Hunt, 1996;Kokubun et al, 2008), with foraging efforts often focused below the thermocline in stratified water (Kokubun et al, 2008;Takahashi et al, 2008).…”

Section: Foraging Behaviormentioning

confidence: 99%

Does location really matter? An inter-colony comparison of seabirds breeding at varying distances from productive oceanographic features in the Bering Sea

Harding

Paredes

Suryan

et al. 2013

Deep Sea Research Part II: Topical Studies in Oceanography

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a b s t r a c tCentral place foragers, such as breeding seabirds, need to commute between their nests and foraging grounds, thus close proximity of the breeding colony to productive oceanographic features might be beneficial for seabird reproduction. We tested this hypothesis by investigating the at-sea foraging and breeding behavior of thick-billed murres (Uria lomvia) nesting at three colonies (Bogoslof, St. Paul, and St. George Islands) in the Bering Sea located at different distances from the productive continental shelf-break. We found that distances to feeding areas differed only during night trips among colonies. St. Paul murres foraged entirely on the shelf, whereas St. George murres commuted to the continental shelf-break at night and foraged on the shelf during the day. Bogoslof murres foraged in oceanic waters in close proximity to the colony. Murres breeding at the both Pribilof colonies spent less time attending nests and had higher levels of stress hormone corticosterone compared to murres breeding at Bogoslof, although chick-provisioning rates and fledging success were similar among the three colonies. Lower nest attendance and higher corticosterone suggest lower food availability in the Pribilof domain compared to the Bogoslof region. Murres breeding at the Pribilofs used different foraging strategies to buffer effects of food shortages on their reproduction: flight costs associated with longer distance night trips at St. George were presumably balanced by benefits of higher density and/or more lipid rich prey in the continental shelf-break regions, whereas the additional distance of St. Paul from the continental shelf-break may have outweighed any energetic gain. Murres exhibited a remarkable degree of plasticity of foraging strategies in response to changes in their food availability, but the breeding success of murres did not reflect either food limitations or the colony proximity to productive oceanographic features.

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Foraging by murres (Uria spp.) at tidal fronts surrounding the Pribilof Islands, Alaska, USA

Cited by 93 publications

References 16 publications

Climate change and the control of energy flow in the southeastern Bering Sea

Climate change and the control of energy flow in the southeastern Bering Sea

In situ observations of the association between juvenile fishes and scyphomedusae in the Bering Sea

Does location really matter? An inter-colony comparison of seabirds breeding at varying distances from productive oceanographic features in the Bering Sea

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