Journal
JOURNAL OF THE ROYAL SOCIETY INTERFACE
Volume 10, Issue 78, Pages -Publisher
ROYAL SOC
DOI: 10.1098/rsif.2012.0477
Keywords
whale shark; thermal recovery; Rhincodon typus; vertical migration; diving behaviour
Categories
Ask authors/readers for more resources
Many fishes make frequent ascents to surface waters and often show prolonged surface swimming following descents to deep water. This affinity for the surface is thought to be related to the recovery of body heat lost at depth. We tested this hypothesis using data from time-depth recorders deployed on four whale sharks (Rhincodon typus). We summarized vertical movements into bouts of dives and classified these into three main types, using cluster analysis. In addition to day and night 'bounce' dives where sharks rapidly descended and ascended, we found a third type: single deep (mean: 340 m), long (mean: 169 min) dives, occurring in daytime with extremely long post-dive surface durations (mean: 146 min). Only sharks that were not constrained by shallow bathymetry performed these dives. We found a negative relationship between the mean surface duration of dives in the bout and the mean minimum temperature of dives in the bout that is consistent with the hypothesis that thermoregulation was a major factor driving use of the surface. The relationship broke down when sharks were diving in mean minimum temperatures around 25 degrees C, suggesting that warmer waters did not incur a large metabolic cost for diving and that other factors may also influence surface use.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available