Abstract
Whale shark (Rhincodon typus) tourism is increasingly popular at predictable aggregations around the world, but only a few use provisioning to ensure close interactions. Understanding the effects of provisioning on the behaviour of this endangered species is critical to manage this growing industry. We recorded the diving behaviour and habitat use of juvenile whale sharks (n = 4) for a mean of 49.5 provisioned and 33.8 non-provisioned days using temperature-depth-recorders. We found that time spent at the surface (< 2 m) between 6 am and 1 pm increased ~ sixfold, while timing of deep dives shifted from 4–10 am to 10 am–2 pm, i.e. near or at the end of the provisioning activities. The shift might be related to a need to thermoregulate following a prolonged period of time in warmer water. These changes could have fitness implications for individuals frequently visiting the provisioning site. Based on recorded amount of time spent in warm waters and published Q10 values for ectotherms, we estimate a 7.2 ± 3.7% (range 1.3–17.8%) higher metabolic rate when sharks frequent the provisioning site. The observed behavioural, habitat use, and potential fitness shifts should be considered when developing guidelines for sustainable tourism, particularly in light of new provisioning sites developing elsewhere.
Highlights
Whale shark (Rhincodon typus) tourism is increasingly popular at predictable aggregations around the world, but only a few use provisioning to ensure close interactions
Morning provisioning was followed by different shark depth-use patterns throughout the remainder of the day: the timing of deep dives shifted, with few dives exceeding 200 m occurring during the early morning and most occurring at the end of the provisioning period
Provisioning of elasmobranchs continues to be a debated topic, with the general understanding that a lack of baseline data on the biology, ecology, and physiology of these species complicates the interpretation of findings from provisioning s ites[6,64,65]
Summary
Whale shark (Rhincodon typus) tourism is increasingly popular at predictable aggregations around the world, but only a few use provisioning to ensure close interactions. The shift might be related to a need to thermoregulate following a prolonged period of time in warmer water These changes could have fitness implications for individuals frequently visiting the provisioning site. Tagging of juvenile whale sharks suggest that they are a primarily epipelagic, staying above 240 m most of their time, but known to reach depths of over 1900 m29,30 Such epipelagic fish are known to move frequently through the water column, which has been suggested to be driven by the need for prey detection, reduced energy expenditure, thermoregulation, or n avigation[31,32,33,34]. Sex Size (m) Date first tagged No of days sighted before deployment No of days tagged Provisioned days
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
