On the food of northern krill Meganyctiphanes norvegica in relation to its vertical distribution

Lass, Sandra; Tarling, Geraint A.; Virtue, Patti; Matthews, J. B. L.; Mayzaud, Patrick; Búchholz, Friedrich

doi:10.3354/meps214177

Cited by 48 publications

(65 citation statements)

References 44 publications

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“…Accordingly, a low content of 16:1(n À 7) and high contents of 20:1(n À 9) and 22:1(n À 11) as found in krill from Ullsfjorden may reflect a carnivorous or omnivorous diet with copepods as the major food component (Saether et al 1986). Similarly, high levels of 20:1(n À 9) and 22:1(n À 11) are indicative of heavy predation on copepods by, for example, krill from the Kattegat , as confirmed by stomach analysis (Lass et al, 2001). Virtue et al (2000) distinguished the predominant diet of krill from the Ligurian Sea, the Kattegat, and the Clyde Sea by means of their fatty acid composition.…”

Section: Fatty Acids As Trophic Markersmentioning

confidence: 60%

“…Fatty alcohols derived from WE have been found in the stomachs of krill (Lass et al, 2001) but only trace amounts of WE occur in the rest of the body. Apparently, M. norvegica catabolizes WE and fatty alcohols from prey both quickly and efficiently.…”

Section: Fatty Acids As Trophic Markersmentioning

confidence: 99%

“…Apparently, dietary PUFA were selectively metabolised by krill. Lass et al (2001) analysed the FA composition of the stomach contents and found high amounts of still undigested fatty alcohols from copepods and phytol from microalgae. Unfortunately, this approach is tedious due to the small amount of sample available for analysis.…”

Section: Fatty Acids As Trophic Markersmentioning

confidence: 99%

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Physiology and Metabolism of Northern Krill (Meganyctiphanes norvegica Sars)

Spicer

Saborowski

2010

Advances in Marine Biology

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Section: Fatty Acids As Trophic Markersmentioning

confidence: 60%

Section: Fatty Acids As Trophic Markersmentioning

confidence: 99%

Section: Fatty Acids As Trophic Markersmentioning

confidence: 99%

See 1 more Smart Citation

Physiology and Metabolism of Northern Krill (Meganyctiphanes norvegica Sars)

Spicer

Saborowski

2010

Advances in Marine Biology

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“…Recent results underline that M. norvegica is an opportunistic feeder and feeds on both phyto-and zooplankton (Bamstedt and Karlson 1998;Onsrud and Kaartvedt 1998). A thorough comparison of food sources in the water columns of the Clyde Sea and Kattegat and food selection by stomach contents analysis is given in Lass et al (2000) and by lipid analysis in Virtue et al (2000).…”

Section: Trophic Conditionsmentioning

confidence: 99%

Metabolic and enzymatic adaptations in northern krill,Meganyctiphanes norvegica, and Antarctic krill,Euphausia superba

Búchholz¹,

Saborowski²

2000

Can. J. Fish. Aquat. Sci.

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Abstract:The Antarctic krill, Euphausia superba, is restricted to the Antarctic Ocean. The northern krill, Meganyctiphanes norvegica, is extremely widely distributed from the arctic North Atlantic to the warm Mediterranean. Respiration measurements showed no seasonal differences in rates determined in krill from the thermally stable Clyde Sea (Scotland) and the cooler but variable Danish Kattegat. In the warm Ligurian Sea, where temperatures are stable, krill showed higher rates in April than in September, indicating reactions to the short but intensive productive season. Krill can passively benefit from enhancements of overall metabolism when ascending into upper, warmer water strata during their pronounced diel vertical migration. Michaelis-Menten constants (K m ) of citrate synthase (CS) were compared. In terms of respiration and enzyme regulation, krill from the Ligurian Sea stand apart: temperature and nutrition appear to be of different influence, relatable to genetic differentiation in the species. In contrast, K m of CS in E. superba is temperature independent, highlighting the species' stenothermal physiology. A basal level of activity of digestive enzymes ensures immediate utilization of patchy food sources. Specific induction, including that of chitinases, indicating omnivory in both species, underlines krill's exceptional capacity to adapt to highly variable trophic environments. Processes of moult, growth, and reproduction are locally and seasonally adjusted.Résumé : Le krill antarctique, Euphausia superba, n'habite que l'Océan antarctique, alors que le krill nordique, Meganyctiphanes norvegica, possède une répartition géographique très étendue qui va de la région arctique de l'Atlantique Nord aux eaux chaudes de la Méditerranée. Les taux respiratoires n'accusent pas de variation saisonnière chez le krill de la mer de Clyde en Écosse, un milieu à forte stabilité thermique, ni chez celui du Cattégat danois, une mer plus froide et plus changeante. Dans la mer Ligurienne, où les températures sont chaudes et stables, le krill a des taux respiratoires plus élevés en avril qu'en septembre, en réaction à la courte mais intense saison de production. Le krill peut bénéficier passivement d'un accroissement général de son métabolisme lorsqu'il se déplace vers les couches d'eau supérieures plus chaudes durant sa migration verticale quotidienne marquée. Nous avons comparé les constantes de Michaelis-Menten (K m ) de la citrate synthase (CS). En ce qui a trait à la respiration et la régulation enzymatique, le krill de la mer Ligurienne fait bande à part: la température et la nutrition semblent y avoir une influence particulière, à cause d'une différentiation génétique chez l'espèce. En revanche, la K m de la citrate synthase est indépendante de la température chez E. superba, une caractéristique physiologique d'une espèce sténotherme. Le maintien d'un niveau d'activité de base chez les enzymes digestives permet l'utilisation immédiate de ressources alimentaires à répartition contagieuse. L'induction spécifique, e...

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“…A subsequent pulse of productivity may induce synchrony again. Linked to a flexible omnivorous diet (Lass et al, 2001), such synchronisation may be a plastic physiological reaction to temporal oscillations in the trophic environment. Synchronisation was also found in Antarctic krill (Buchholz, 1985) and a recent study in Euphausi hanseni indicated that moult and spawning may be closely controlled by up-welling events which induce sudden changes in trophic conditions (Buchholz, unpublished).…”

Section: Growth In the Field Along A Climatic Gradientmentioning

confidence: 99%