Trophic implications of cross-shelf copepod distributions in the Southeastern Bering Sea

Cooney, Robert T.; Coyle, Kenneth O.

doi:10.1007/bf00397684

Cited by 123 publications

(57 citation statements)

References 10 publications

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“…Predation by juvenile pollock in that year may have limited the impact of copepod grazing more severely than usual. During a 15-yr study of the eastern Bering Sea, including the shelf, between 1956 and 1970, Ikeda andMotoda (1978, in Cooney andCoyle, 1982) obtained grazing rates approximately 30% higher than those of Cooney and Coyle, indicating that copepod populations may have been more closely coupled to phytoplankton than in 1979. It is possible that we have underestimated zooplankton grazing rates, but the presence of a strong annual spring bloom suggests that, at least during the bloom, copepods are not limited by food availability.…”

Section: Mechanisms For Change In Zooplankton Populationsmentioning

confidence: 96%

“…Dagg et al (1982) estimated that meso-zooplankton grazing in 1979 accounted for only 18% of daily phytoplankton production in the outer shelf and 25% in the middle shelf domain, and that temperature, rather than food availability, limited copepod growth rates by its effects on zooplankton metabolic processes. Cooney and Coyle (1982), also working in 1979, estimated that copepods consumed 20-30% of primary production in the outer domain, and rarely > 5% of primary production in the middle domain.…”

Section: Mechanisms For Change In Zooplankton Populationsmentioning

confidence: 99%

“…The estimates of meso-zooplankton grazing rates by Dagg et al (1982) and Cooney and Coyle (1982) were conducted in a year of unusually high abundance of age-1 pollock. Predation by juvenile pollock in that year may have limited the impact of copepod grazing more severely than usual.…”

Section: Mechanisms For Change In Zooplankton Populationsmentioning

confidence: 99%

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Climate change and control of the southeastern Bering Sea pelagic ecosystem

Hunt

Stabeno

Walters

et al. 2002

Deep Sea Research Part II: Topical Studies in Oceanography

501

385

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We propose a new hypothesis, the Oscillating Control Hypothesis (OCH), which predicts that pelagic ecosystem function in the southeastern Bering Sea will alternate between primarily bottom-up control in cold regimes and primarily top-down control in warm regimes. The timing of spring primary production is determined predominately by the timing of ice retreat. Late ice retreat (late March or later) leads to an early, ice-associated bloom in cold water (e.g., 1995, 1997, 1999), whereas no ice, or early ice retreat before mid-March, leads to an open-water bloom in May or June in warm water (e.g., 1996, 1998, 2000). Zooplankton populations are not closely coupled to the spring bloom, but are sensitive to water temperature. In years when the spring bloom occurs in cold water, low temperatures limit the production of zooplankton, the survival of larval/juvenile fish, and their recruitment into the populations of species of large piscivorous fish, such as walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus) and arrowtooth flounder (Atheresthes stomias). When continued over decadal scales, this will lead to bottom-up limitation and a decreased biomass of piscivorous fish. Alternatively, in periods when the bloom occurs in warm water, zooplankton populations should grow rapidly, providing plentiful prey for larval and juvenile fish. Abundant zooplankton will support strong recruitment of fish and will lead to abundant predatory fish that control forage fish, including, in the case of pollock, their own juveniles. Piscivorous marine birds and pinnipeds may achieve higher production of young and survival in cold regimes, when there is less competition from large piscivorous fish for coldwater forage fish such as capelin (Mallotus villosus). Piscivorous seabirds and pinnipeds also may be expected to have high productivity in periods of transition from cold regimes to warm regimes, when young of large predatory species of fish are numerous enough to provide forage. The OCH predicts that the ability of large predatory fish populations to sustain fishing pressure will vary between warm and cold regimes.The OCH points to the importance of the timing of ice retreat and water temperatures during the spring bloom for the productivity of zooplankton, and the degree and direction of coupling between zooplankton and forage fish. in the biomass of large piscivorous fish and a concurrent decline in the biomass of forage fish, including age-1 walleye pollock, particularly over the southern portion of the shelf. Populations of northern fur seals (Callorhinus ursinus) and seabirds such as kittiwakes (Rissa spp.) at the Pribilof Islands have declined, most probably in response to a diminished prey base. The available evidence suggests that these changes are unlikely the result of a decrease in total annual new primary production, though the possibility of reduced post-bloom production during summer remains. An ecosystem approach to management of the Bering Sea and its fisheries is of great importance if all o...

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Section: Mechanisms For Change In Zooplankton Populationsmentioning

confidence: 96%

Section: Mechanisms For Change In Zooplankton Populationsmentioning

confidence: 99%

See 1 more Smart Citation

Climate change and control of the southeastern Bering Sea pelagic ecosystem

Hunt

Stabeno

Walters

et al. 2002

Deep Sea Research Part II: Topical Studies in Oceanography

501

385

View full text Add to dashboard Cite

show abstract

“…It is unlikely to apply to the coastal domain, as the inner front appears to block age-0 pollock from that region (Kachel et al, 2002;Hunt et al, 2002). It is also unclear whether the OCH applies in the outer domain, as most of the copepod biomass there consists of large oceanic species with annual life cycles and the ability to graze the bloom very early in the spring (Cooney & Coyle, 1982). In addition, sea ice occurs rarely over the outer shelf south of the Pribilof Islands.…”

Section: The Oscillating Control Hypothesismentioning

confidence: 99%

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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“…Furthermore, nearly 70% of the resulting carbon fixed in the southeast Chukchi from water column primary production is believed to settle to the sea floor where it can be utilized by benthic fauna (Cooney and Coyle 1982, Walsh et al 1989, McTigue et al 2015.…”

Section: Introductionmentioning

confidence: 99%