Abstract

Whale sharks, the world’s largest fish, are a focal species for marine tourism industries in all the tropical oceans. However, most whale shark ‘hotspots’ are linked to ephemeral biological phenomena such as fish spawning events, meaning the sharks are present for only a few days or weeks of the year. Sexual segregation is inherent within these coastal feeding aggregations, which are significantly dominated by juvenile male sharks. Once they disperse, their movements are largely a mystery. Basic questions about the biology and ecology of whale sharks still remain unanswered. Where are the females? Where are the adults? Satellite-tagging studies have proven that whale sharks routinely travel thousands of kilometres through the open ocean but, in an apparent contradiction, photo-matching comparisons between major aggregation sites have shown little evidence of connectivity. The advent of a global database for whale shark identification photographs (www.whaleshark.org) has helped to reinvent the way these ocean giants are researched through recruiting thousands of scientists and SCUBA divers from 45+ countries to one cooperative project. Coupled with use of the latest electronic tags and chemical techniques, this initiative may finally allow us to find these elusive ‘lost giants’.