Body shrinkage as a possible over-wintering mechanism of the Antarctic krill, Euphausia superba Dana

Ikeda, Tom; Dixon, Paul

doi:10.1016/0022-0981(82)90088-0

Cited by 186 publications

(143 citation statements)

References 11 publications

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“…Since reduction in body size in crustaceans is only possible through moulting, these values indicate that shrinkage must have occurred. A similar trend during starvation of 211 days has been observed by Ikeda and Dixon (1982) and in another 207-day starvation experiment by O'Brien et al (2011). Shrinkage at moult would contribute to preservation of body functions with fewer reserves available.…”

Section: Physical and Metabolic Changes During Starvationsupporting

confidence: 80%

Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

et al. 2015

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Adult Euphausia superba survive winter without or with little feeding. It is not exactly known whether the scarcity of food or an internal clock, set by the natural Antarctic light regime, are responsible for non-feeding. Our research questions were therefore the following: (1) How will physiological and biochemical conditions of krill change during long-term starvation at constant light regime? (2) If and how do enzyme activities change during such starvation? (3) What is the influence of food availability versus that of light regime? To answer these questions, adult krill were starved under laboratory conditions for 12 weeks with constant light regime (12:12; dark/light) and the impact on physiological functions was studied. Initial experimental condition of krill resembled the condition of late spring krill in the field with fully active metabolism and low lipid reserves. Metabolic activity and activities of enzymes catabolising lipids decreased after the onset of starvation and remained low throughout, whereas lipid reserves declined and lipid composition changed. Mass and size of krill decreased while the inter-moult period increased. Depletion of storage-and structural metabolites occurred in the order of depot lipids and glycogen reserves after onset of starvation until proteins were almost exclusively used after 6-7 weeks of starvation. Results confirmed various proposed overwintering mechanisms such as metabolic slowdown, slow growth or shrinkage and use of lipid reserves. However, these changes were set in motion by food shortage only, i.e. without the trigger of a changing light regime.

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Section: Physical and Metabolic Changes During Starvationsupporting

confidence: 80%

Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

et al. 2015

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“…Winter-over strategies documented for Euphausia superOO include shrinkage [Ikeda and Dixon , 1982; Quelin and Ross, 1991], metabolic reduction [Kawaguchi el al., 1986;Quelin and Ross, 1991;Torres el al ., 1994], and lipid storage and depletion [Quelin and Ross. 1991;Torres el al., 1994].…”

Section: 12mentioning

confidence: 99%

Factors affecting distribution and abundance of zooplankton, with an emphasis on Antarctic krill, Euphausia superba

Quetin

Ross

Frazer

et al. 1996

Antarctic Research Series

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Variation in the abundance and distribution ci zooplankton is an inherent characteristic ci pelagic marine ecosystems. In this chapter, we discuss how patterns of abundance and distribution &JC affected by the life cycle characteristics c:I some rl the predominant macrowoplankton west c::l the Antarctic Peninsula.Because ci the importance of Antarctic krill, EuphausitJ Sllptrba. within this region, some aspects ci its ecoiolY ~ given special .uentian. Of particular relevance to rum:nt hypotheses is the association of krill and sea icc , and new evidence is presented for winter habilal Icgreg_tion between adult and larval Slages. Subsequent discussion focuses 00 strategies for winter survival, and variation in recruilmenl. Finally, we discuss the effects of abiotic facton such as frontal shifts, and biotic factors such as food composition, as they ~late to abundance and distribution ci zooplankton .

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“…• The reduction in metabolic rates (Kawaguchi et al 1986;Quetin and Ross 1991;Torres et al 1994a) • The utilisation of stored body lipids Hagen et al 2001) • Shrinkage in size and utilisation of body protein (Ikeda and Dixon 1982;Quetin and Ross 1991) Utilisation of food sources other than phytoplankton in the water column:…”

Section: Introductionmentioning

confidence: 99%

“…The current discussions on a long-term decline of krill abundance in the SW Atlantic sector of the Southern Ocean due to environmental changes will be evaluated with regards to the energetic demands of larval and adult krill throughout the seasons. Ikeda and Dixon (1982) Feeding on ice algae Investigated the ability of krill to feed on ice algae and readdressed the question on how krill overwinter Hamner et al (1983) Benthic feeding Showed evidence for benthic feeding by krill in winter Kawaguchi et al (1986) Reduced feeding and metabolism, switching food sources, lipid utilisation and shrinkage…”

Section: Introductionmentioning

confidence: 99%

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

2011

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A major aim of this review is to determine which physiological functions are adopted by adults and larvae to survive the winter season with low food supply and their relative importance. A second aim is to clarify the extent to which seasonal variation in larval and adult krill physiology is mediated by environmental factors with a strong seasonality, such as food supply or day light. Experimental studies on adult krill have demonstrated that speciWc physiological adaptations during autumn and winter, such as reduced metabolic rates and feeding activity, are not caused simply by the scarcity of food, as was previously assumed. These adaptations appear to be inXuenced by the local light regime. The physiological functions that larval krill adopt during winter (reduced metabolism, delayed development, lipid utilisation, and variable growth rates) are, in contrast to the adults, under direct control by the available food supply. During winter, the adults often seem to have little association with sea ice (at least until early spring). The larvae, however, feed within sea ice but mainly on the grazers of the ice algal community rather than on the algae themselves. In this respect, a miss-match in timing of the occurrence of the last phytoplankton blooms in autumn and the start of the sea ice formation, as has been increasingly observed in the west Antarctic Peninsula (WAP) region, will impact larval krill development during winter in terms of food supply and consequently the krill stock in this region.

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Body shrinkage as a possible over-wintering mechanism of the Antarctic krill, Euphausia superba Dana

Cited by 186 publications

References 11 publications

Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

Factors affecting distribution and abundance of zooplankton, with an emphasis on Antarctic krill, Euphausia superba

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

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