Where the whale sharks are: An innovative satellite tagging programme to track the movements of whale sharks from Ningaloo Reef, Western Australia

Abstract

Background Coastal aggregations of whale sharks, typically dominated by juvenile males and occurring seasonally, are now documented in many places around the world, including Ningaloo Reef, Western Australia (WA). This aggregation occurs during the Austral autumn and winter and supports a lucrative tourism industry which operates during the whale shark “season” (generally April – July). Despite being one of the most highly studied aggregations of whale sharks in the world, their location and movements outside this period remain poorly understood, but are critical for understanding long term population dynamics and for effective management and conservation. An earlier study by ECOCEAN, combining satellite tracking and citizen science sightings of whale sharks outside the “season” at Ningaloo Reef and elsewhere along the WA coast, indicates that whale sharks may move north and south along the coast throughout the year, and/or make relatively short migrations, rather than undertaking long, trans-oceanic migrations. To test this further, a novel satellite tagging programme, supported by The Western Australian Department of Education (The Department), aims to discover where the whale sharks are when they are not at Ningaloo Reef and determine whether there are other unidentified “hotspots” for foraging and/or migration, i.e. areas of habitat critical for whale sharks. This programme also aims to provide innovative learning opportunities for school children, to make them more aware of the biology and ecology of WA's marine emblem and the marine environment, as well as to encourage engagement with STEM (Science, Technology, Engineering and Maths) learning. Approach Satellite tags (Wildlife Computers SPOT tags) were deployed on 12 whale sharks (identified using photo-identification through the Wildbook for Whale Sharks) at Ningaloo Reef in July 2015 using a custom-made clamp attachment on the first dorsal fin, designed to have minimal impact on the animals. Tags were funded by 16 schools from around WA participating in a joint ECOCEAN - Western Australian Department of Education science learning programme. Tracks of the sharks are displayed publically on the ZoaTrack website (www.zoatrack.org/projects/243/ analysis) and were used by participating schools in an eight week teaching programme. Results Data from satellite tags deployed in 2015 are still being collected and will be analysed as part of an Honours project in 2016, however, the teaching programme proved highly successful: The Department developed a comprehensive suite of resources addressing science, technology, engineering, mathematics and arts subjects to support students to engage in authentic learning experiences, and classes from pre-primary through to senior high school were involved. Preliminary results from the tags show that all have successfully reported positional data, for periods ranging from 15 to 156 days (mean 93.4 ± 13.1 SE) (as at 31/12/15). Homing migrations, to the southern part of Ningaloo Reef, have been recorded for 50% of all the sharks tagged, within periods ranging from 44 to 93 days (mean 65.7 ± 7.8 SE). These data show sharks making short forays away from Ningaloo Reef, and reveal areas important for commuting and foraging. Conclusions This innovative approach to funding allowed the satellite tracking programme to proceed and not only provided new information on the movements of whale sharks from Ningaloo Reef that can be used for conservation planning and management, but also provided novel learning experiences for school children and raised awareness for whale shark conservation and the marine environment. The data gathered support the hypothesis that whale sharks from the Ningaloo Reef aggregation do not typically undertake ocean basin scale migrations, rather they make shorter forays, perhaps to exploit food resources that vary spatially and temporally, and could be used to benchmark conservation outcomes for WA whale sharks and to provide pathways for more effective protection.