Whale sharks have been fished throughout their range, and their flesh is highly valued in some Asian markets. The recent increase in the demand for shark-fin soup threatens this species; in 1999, a large whale shark fin sold for around £11,000 (9). Although little is known about the ecology of this species, it is likely to be long-lived with a slow reproduction rate, making populations particularly vulnerable to exploitation. Where these shy creatures regularly come close to shore, they have become important tourist attractions, but the impact of shark-watching tours is at present poorly understood (5).