Feeding sharks at offshore dive sites does not appear to adversely affect shark behaviour, according to a new study into the booming ecotourism industry.

Researchers at the University of Miami's Rosenstiel School of Marine & Atmospheric Science set out to see whether providing chum — ground-up fish — to attract big sharks for dive tourists changed the way sharks behaved.

These dive operations, which have become a highly lucrative industry around the world, have generated significant criticism over worries that feeding the species could make it more vulnerable to threats.

To find out if the worries were justified, the researchers tagged two groups of tiger sharks — one just off Florida and one in the Bahamas — and tracked their behaviour and movement by satellite over the long-term to see if dive tourism was affecting them.

Roaming behaviour not affected

The researchers' hypothesis before they began the study was that the tiger sharks at the Bahamas site would show restricted movements around the dive site because dive operators in the Bahamas are allowed to use chum to attract sharks. In Florida waters, the use of chum to attract sharks is illegal.

But what they found was just the opposite. Tiger sharks at the Bahamas site roamed over an area of 8,500 square kilometres — almost five times greater than the range of the tiger sharks in Florida.

"Not only did we discover that ecotourism provisioning did not affect tiger shark behaviour, we found that tiger sharks undergo previously unknown migrations up to 3,500 kilometres into the open Atlantic," said researcher Jerald Ault.

"Given the economic and conservation benefits, we believe managers should not prevent shark diving tourism out of hand until sufficient data were to demonstate otherwise," said report co-author Neil Hammerschlag.

In a study Hammerschlag carried out last year, he found that shark dive tourism generated more money for local economies than killing sharks for their fins. Shark finning has been blamed for a huge decline in shark populations.

The researchers' findings are published in the British Ecological Society's journal, Functional Ecology.

The paper is titled, Don't bite the hand that feeds: Assessing ecological impacts of provisioning ecotourism on an apex marine predator.