Publications des scientifiques de l'IRD

Alegre A., Ménard Frédéric, Tafur R., Espinoza P., Arguelles J., Maehara V., Flores O., Simier Monique, Bertrand Arnaud. (2014). Comprehensive model of jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt Current System. Plos One, 9 (1), e85919. ISSN 1932-6203.

Titre du document
Comprehensive model of jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt Current System
Année de publication
2014
Type de document
Article référencé dans le Web of Science WOS:000330240500089
Auteurs
Alegre A., Ménard Frédéric, Tafur R., Espinoza P., Arguelles J., Maehara V., Flores O., Simier Monique, Bertrand Arnaud
Source
Plos One, 2014, 9 (1), e85919 ISSN 1932-6203
The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Ecologie, systèmes aquatiques [036]
Description Géographique
PEROU
Localisation
Fonds IRD [F B010061744]
Identifiant IRD
fdi:010061744
Contact