Publications des scientifiques de l'IRD

Ruzicka J. J., Steele J. H., Ballerini Tosca, Gaichas S. K., Ainley D. G. (2013). Dividing up the pie : whales, fish, and humans as competitors. Progress in Oceanography, 116, p. 207-219. ISSN 0079-6611.

Titre du document
Dividing up the pie : whales, fish, and humans as competitors
Année de publication
2013
Type de document
Article référencé dans le Web of Science WOS:000324455600014
Auteurs
Ruzicka J. J., Steele J. H., Ballerini Tosca, Gaichas S. K., Ainley D. G.
Source
Progress in Oceanography, 2013, 116, p. 207-219 ISSN 0079-6611
Similarly structured food web models of four coastal ecosystems (Northern California Current, Central Gulf of Alaska, Georges Bank, southwestern Antarctic Peninsula) were used to investigate competition among whales, fishes, pinnipeds, and humans. Two analysis strategies simulated the effects of historic baleen and odontocete whale abundances across all trophic levels: food web structure scenarios and time-dynamic scenarios. Direct competition between whales and commercial fisheries is small at current whale abundances; whales and fisheries each take similar proportions of annual pelagic fish production (4-7%). Scenarios show that as whale populations grow, indirect competition between whales and fish for zooplankton would more likely impact fishery production than would direct competition for fish between whales and commercial fisheries. Increased baleen whale abundance would have greater and broader indirect effects on upper trophic levels and fisheries than a similar increase in odontocete abundance. Time-dynamic scenarios, which allow for the evolution of compensatory mechanisms, showed more modest impacts than structural scenarios, which show the immediate impacts of altered energy pathways. Structural scenarios show that in terms of energy availability, there is potential for large increases in whale abundance without major changes to existing food web structures and without substantial reduction of fishery production. For each ecosystem, a five-fold increase in baleen whale abundance could be supported with minor disruptions to existing energy flow pathways. However, such an increase would remain below historical population levels for many cetaceans. A larger expansion (20X) could be accommodated only with large reductions in energy flow to competitor groups. The scope for odontocete expansion varies between ecosystems but may be more restricted than the scope for baleen expansion because they feed at higher, less productive trophic levels.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Ecologie, systèmes aquatiques [036] ; Ressources halieutiques [040]
Description Géographique
AMERIQUE DU NORD ; PACIFIQUE NORD ; ATLANTIQUE NORD ; ANTARCTIQUE
Localisation
Fonds IRD [F B010060670]
Identifiant IRD
fdi:010060670
Contact