Sharks swimming free in the oceans may soon become more valuable as tourist attractions than when caught, sliced up and served in soup, a global study showed on Friday.
It urged better protection for the fish, from Australia to the Caribbean, to reduce catches of an estimated 38 million a year to meet demand for shark fin soup, mainly in China.
"We are hoping that people will recognize that sharks are not only valuable on the plate," lead author Andres Cisneros-Montemayor of the University of British Columbia in Canada said.
Shark-watching tourism generates about $314 million a year and is projected to surge to $780 million in the next 20 years, according to the study in the journal Oryx - The International Journal of Conservation.
By contrast, the landed value of world shark fisheries is now $630 million a year and has been declining, according to the experts in Canada, the United States and Mexico.
In recent years Palau, the Maldives, Honduras, Tokelau, The Bahamas, the Marshall Islands, the Cook Islands, French Polynesia and New Caledonia have created sanctuaries by banning commercial shark fishing.
"Many countries have a significant financial incentive to conserve sharks and the places where they live," said Jill Hepp, director of global shark conservation at the Pew Charitable Trusts which took part in the study. Pew urged more sanctuaries.
The study is one of many about how to aid world fisheries, hit by pollution and over-fishing. Tourism draws almost 600,000 people annually to watch sharks from hammerheads to great whites, supporting 10,000 jobs in 29 countries, it said.
One problem is the separate sources of demand - Asian lovers of shark fin soup are unlikely to abandon the dish in favor of tourism, which has so far been mainly for Westerners.
Fishermen need to see a higher value from organizing tourism - such as running boat trips to view sharks or renting scuba gear - than from killing them for fins, said Carl Gustaf Lundin, director of the global marine program at the International Union for Conservation of Nature, which was not involved in the study.