Fine-scale vertical movements of oceanic whitetip sharks (Carcharhinus longimanus)
|Author(s)||Tolotti Mariana1, 2, Bauer Robert1, Forget Fabien1, Bach Pascal1, Dagorn Laurent1, Travassos Paulo3|
|Affiliation(s)||1 : Inst Rech Dev, UMR, Marine Biodivers Exploitat & Conservat MARBEC, Ave Jean Monnet CS 30171, F-34203 Sete, France.
2 : Univ Fed Pernambuco, Dept Oceanog, Ave Prof Moraes Rego,1235 Cidade Univ, BR-50670901 Recife, PE, Brazil.
3 : Univ Fed Rural Pernambuco, Dept Pesca & Aquicultura, Rua Dom Manoel de Medeiros S-N Dois Irmaos, BR-52171900 Recife, PE, Brazil.
|Source||Fishery Bulletin (0090-0656) (Natl Marine Fisheries Service Scientific Publ Office), 2017 , Vol. 115 , N. 3 , P. 380-395|
|WOS© Times Cited||3|
Time series of depth data, obtained for 6 oceanic whitetip sharks (Carcharhinus longimanus) tagged with pop-up satellite archival tags, were analyzed in detail. The aim was to improve our knowledge of the vertical behavior of this species. Individuals were tagged in the Atlantic Ocean (n=5) and Indian Ocean (n=1) between 2011 and 2012. Deployment periods for these tags varied from 100 to 178 d. The sharks spent most of their time in the mixed layer, displaying the typical behavior of an epipelagic species. However, analyses revealed complex vertical movement patterns, including marked diel changes that reflect 3 different types of behavior. Results of the generalized additive models indicate that vertical movements were strongly correlated with variations in the depth of the mixed layer. A correlation between vertical movements and sea-surface temperature (SST) was also observed. When SST was above average, oceanic whitetip sharks increased their vertical amplitude, disregarding the reduction of the mixed layer. Thermoregulation likely allows this type of vertical movement.