|A global perspective on the trophic geography of sharks |
Auteur(s): Bird Christopher s., Verissimo Ana, Magozzi Sarah, Abrantes Katya g., Aguilar Alex, Al-reasi Hassan, Barnett Adam, Bethea Dana m., Biais Gerard, Borrell Asuncion, Bouchoucha Marc, Boyle Mariah, Brooks Edward j., Brunnschweiler Juerg, Bustamante Paco, Carlisle Aaron, Catarino Diana, Caut Stephane, Cherel Yves, Chouvelon Tiphaine, Churchill Diana, Ciancio Javier, Claes Julien, Colaco Ana, Courtney Dean l., Cresson P., Daly Ryan, De necker Leigh, Endo Tetsuya, Menard F.
(Article) Publié: -Nature Ecology Evolution, vol. 2 p.299-+ (2018)
Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30 degrees and 50 degrees of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.