Thanks to the high re-sighting rate we can apply robust models and find out if the population is recovering or if more strict protection is needed to save the species. We use Mafia Island as a best-case scenario example for a population size analysis to determine their trend over the last 8 years. Kinship analysis may reveal close relatives, such as siblings. We collected tissue samples of most whale sharks at Mafia Island and use them to examine the genetic connectivity between individuals here and elsewhere around the world. Next, we plan to assess their diet in more detail with fatty acid analyses of bulk tissue and of particular compounds. We take small tissue biopsies and use stable isotope analysis to investigate the sharks’ position in the food web and where they have been feeding (geographically), and we use fatty acid analysis to examine potential prey sources other than surface zooplankton.We already compared stable isotope values of whale sharks at Mafia Island with those from elsewhere in the Western Indian Ocean to show that each group feeds in their own latitudinal range without overlapping. We can also examine their feeding ecology over long periods, rather than merely observing what they eat during the day in the high season, by using biochemical analyses. We collected plankton samples from whale shark feeding events and compared them to background samples to show the large biomass of zooplankton that is required for whale sharks to gain energy when feeding. Their short– and long-term feeding ecology. This information is now used to lobby for protection measures, such as a go-slow zone for boats. We also mapped their activity hotspots and found out how these change over time. We found that many individuals stay off Mafia Island throughout the year, despite a seasonal bias in sightings. We have used passive acoustic telemetry to track their movements even when we are not there to monitor. The whale sharks’ fine-scale movements and habitat use.
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