Tuesday, July 23, 2024

Scientists Seek To Understand The Long-Term Effects Of Whale Shark Feeding Practices


Increasing opportunities for up-close encounters with sharks and other animals are making wildlife tourism one of the fastest growing tourism sectors.

This has led Australian ecology experts to venture to one of the world’s main sites to investigate the effects of tourism on endangered whale sharks.

At Oslob in the Philippines, researchers from Flinders University joined local Filipino researchers to measure how the daily feeding regimes for the resident whale shark population might have affected their behavior and physiology by assessing their activity and metabolic requirements.

Oslob is home to one of the world’s largest whale shark tourism sites, and operators use 150kg to 400kg (331 pounds to 882 pounds) of food to attract the impressive animals to the picturesque location.

In the 12 years since feeding whale sharks began, mass tourism at the location has increased the size of shark aggregation as well as changed shark behavior, including “desensitisation” to boat and human contact, researchers have found.

According to Flinders University researcher Christine Barry, who is now doing a PhD at Murdoch University, Western Australia:

“By fitting 16 whale sharks with small accelerometers, similar to a fitness tracker, we found their daily movements and resulting metabolic rate increased by up to 55% in response to their quest for food at the tourism site.

“Our bioenergetics model suggests that providing about 220kg [485 pounds] of food per day would be sufficient to offset higher metabolic rate driven by tourism.

“However, the unknown long-term consequences of feeding whale sharks suggests that managers should focus on making changes to operating procedures to reduce the high activity we see at the site.”

Whale shark (Photo courtesy Dr Gonzalo Araujo (Marine Research and Conservation Foundation, UK)
Whale shark (Photo courtesy Dr Gonzalo Araujo (Marine Research and Conservation Foundation, UK)

Barry hopes her current PhD project will support management at West Australia’s Ningaloo Reef by measuring the importance of foraging ground for this vulnerable species.

Barry and her collaborators’ research on these whale sharks was recently published in the journal Biological Conversation. Check it out here.

(Featured image credit: Dr. Gonzalo Araujo/Marine Research and Conservation Foundation, UK)

John Liang
John Lianghttps://www.deeperblue.com/
John Liang is the News Editor at DeeperBlue.com. He first got the diving bug while in High School in Cairo, Egypt, where he earned his PADI Open Water Diver certification in the Red Sea off the Sinai Peninsula. Since then, John has dived in a volcanic lake in Guatemala, among white-tipped sharks off the Pacific Coast of Costa Rica, and other places including a pool in Las Vegas helping to break the world record for the largest underwater press conference.