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Trophic ecology of the pelagic fish P. antarcticum in East Antarticum

Abstract : The East Antarctic pelagic ecosystem is dominated by the pelagic fish Pleuragramma antarcticum which represents up to 90% of the fish biomass. P. antarcticum is the only species of the Nototheniidae family to have an entire pelagic life cycle. This species is characterized by a particularly long larval stage that lasts over a year and a vertical distribution with larvae in the surface layer and the older individuals in deeper ones. P. antarcticum is planktivorous at all stages of development and is the main prey of numbers of top predators. Thus, P. antarcticum appears as an important species in the ecosystem that links phytoplankton / zooplankton and the higher trophic levels. In this thesis we studied the trophic ecology of this species. In the first part of this study we studied fish larvae abundances and the vertical distribution of all developmental stages. We determined what parameters influenced the individual's larval condition and whether P. antarcticum can be considered as a good indicator of environmental changes. The second part of this thesis intended to clarify trophic relationships of P. antarcticum and its role in the ecosystem. We used different methods which allowed us to analyze the immediate diet (gut contents), the one from a period of few weeks (fatty acids) and finally the integration over a period of a month (stable isotopes). P. antarcticum emerges as a key species in a "wasp waist" ecosystem. As a result, changes in this species could have a significant impact on lower and upper trophic levels.
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Submitted on : Monday, June 3, 2013 - 1:37:37 PM
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  • HAL Id : tel-00829475, version 1

Citation

Carolina Giraldo. Trophic ecology of the pelagic fish P. antarcticum in East Antarticum. Biodiversity and Ecology. Université Pierre et Marie Curie - Paris VI, 2012. English. ⟨NNT : 2012PA066197⟩. ⟨tel-00829475⟩

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