To Feed or Not to Feed? That is the Question

Shark feeding by divers is an emotive subject. Everyone has an opinion, usually based on nothing more than emotion. With all the debate engendered by the Federal proposal to make shark baiting to observe sharks (by divers) illegal in U.S. waters (apart from the purposes of their destruction), it could be time to look at research undertaken by scientists at the University of Miami regarding ecotourism and sharks.

Given that humans have put enormous pressure on the environment and the planet's natural resources, there's a growing impetus for their non-consumptive use, such as viewing sharks instead of killing them.

Sharks are normally elusive, so shark dive operators use bait to attract the sharks. Despite the conservation and economic benefits, people are worried that it could provide a safety threat to humans where sharks learn to associate people with food and that long-term changes in shark behavior could have ecological consequences.

The shark tourism industry is a highly lucrative and booming global market. Does it affect shark populations, such as concentrating them in one location and making them reliant on hand-outs of food from humans?

Until now evidence has been largely rhetorical due to lack of sufficient data to derive any conclusions -- good or bad. Five researchers from the Rosenstiel School of Marine and Atmospheric Science (University of Miami) conducted the first satellite tagging and telemetry study to examine the long-term and long-range movement pattern of tiger sharks (the largest apex predator in tropical waters) in response to shark diving tourism. They studied two separate populations of tiger sharks: One that originated in Florida, where shark feeding has been illegal for 15 years, and the other in the Bahamas, where sharks are regularly fed and observed by divers in an increasingly popular scuba activity.

The team hypothesized that the Bahamas' sharks would exhibit restricted movement around the dive site, especially when compared with those not regularly fed in Florida's waters. They were wrong. Instead, the Bahamas population occupied an area over 8,500 sq. km, almost five times greater than that of the unfed Florida sharks. The Bahamas sharks spent months at sea.

"Not only did we discover that ecotourism provisioning had surprisingly little effect on tiger shark behavior, we found that tiger sharks undergo previously unknown long-distance migrations up to 3,500 km into the open Atlantic," said Jerald S. Ault, professor of marine biology and fisheries. "These apparent feeding forays follow the Gulf Stream, an area of high biological productivity that concentrates shark prey."

Neil Hammerschlag, a research professor and director of the RJ Dunlap Marine Conservation Program and another of the five researchers, said, "Rather than rushing to make conclusions based on fear, we should do the science and make policies based on data. We showed that for tiger sharks, the shark diving eco-tourism taking place in the Bahamas does not impact [their] long-term and large-scale movement and swimming behaviors. Given the economic and conservation benefits, we believe managers should not prevent shark diving tourism out of hand until sufficient data were to demonstrate otherwise."

www.miami.edu/index.php/features/ecotourism_study