MEPS 173:149-162 (1998)  -  doi:10.3354/meps173149

Changes in lipid composition of the Antarctic krill Euphausia superba in the Indian sector of the Antarctic Ocean: influence of geographical location, sexual maturity stage and distribution among organs

P. Mayzaud*, E. Albessard, J. Cuzin-Roudy

Equipe d'Océanographie Biochimique et d'Ecologie, LOBEPM, URA-CNRS 2077, Observatoire Océanologique, BP 28, F-06230 Villefranche sur mer, France

ABSTRACT: Lipid content and lipid class composition of Euphausia superba were studied at different levels for populations and individuals sampled in the Indian sector of the Antarctic Ocean. Strong site-to-site variability was recorded which could only partially be related to sex or development stage differences. Three groups of stations could be differentiated. Northern stations were characterized by 'high lipid-high triglyceride' content, western and eastern locations by 'high lipid-high phosphatidyl choline' content and southern areas by 'low lipid-high phosphatidyl ethanolamine/glycolipid' content. Such variability was likely related to advected populations having spent variable lengths of time in the area studied. Lipid content and class among organs were studied in 5 body fractions: abdomen, stomach, digestive gland, gonad and fat body. In absolute terms, the highest concentrations were observed in the ovaries of mature females and the abdomens of the other stages. In relative terms (% dry weight), the digestive gland displayed the highest level, except in mature females. Distribution varied with stages, with low triglyceride levels in abdomen tissues of most stages and in the fat body and stomach fractions of subadults. High triglyceride levels were recorded in the other fractions for post spawning females and males, as well as in the fat body fraction for mature females and in subadult gonads. A reverse pattern was observed for the relative content of phosphatidyl choline. Phosphatidyl ethanolamine showed maximum values in the abdomen and the gonad. Glycolipid percentages were maximum in the abdomen, suggesting a structural role. The roles of the different lipid classes are discussed with respect to the function of the organ.

KEY WORDS: Krill · Lipids · Spatial heterogeneity · Maturity stage organs

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