Structure, fonctionnement, évolution des communautés benthiques ...

tel-00009359, version 1 - 1 Jun 2005
Chapitre 3 - Fonctionnement du réseau trophique benthique de la Grande Vasière
biomass on the most silty station of the ‘Grande Vasière’ (primary consumers were deposit feeders).
The benthic biomass in Stn. G was dominated by carnivores in late summer, which may be the
consequence of physical and biological disturbances induced by bottom trawling on the benthic
macrofauna. Indeed, the northern part of the study area is the one facing the highest fishing effort, due
to heavy exploitation of Nephrops norvegicus stocks. The overall impact of bottom trawling on the
benthic macrofauna in the study area remains to be determined. Within the central ‘Grande Vasière’
stations, Le Loc’h (2004) showed that the benthic epifauna ≥ 4mm and the demersal fish presented
lowest species richness and diversity in stations A and C, compared to B and D. A and C are the two
of four stations facing the highest fishing effort. Lower sessile-to-mobile abundance ratios and higher
carnivore-to-primary consumer biomass ratios in stations A and C are two other indices of the impact
of bottom-trawling on the benthic fauna of the central ‘Grande Vasière’ (Le Loc’h, 2004).
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