News

Whale sharks ‘exhibit disturbed behaviour in presence of tourist swimmers’

A juvenile whale shark foraging in La Paz Bay, Mexico, as researchers analysed their behaviour when tourists were allowed to shark dive (Joel Gayford/Imperial College London/PA)
A juvenile whale shark foraging in La Paz Bay, Mexico, as researchers analysed their behaviour when tourists were allowed to shark dive (Joel Gayford/Imperial College London/PA) A juvenile whale shark foraging in La Paz Bay, Mexico, as researchers analysed their behaviour when tourists were allowed to shark dive (Joel Gayford/Imperial College London/PA)

Shark tourism – which allows people to dive with the creatures in their natural environment – may be seen as a way to raise money to conserve species but new research suggests it may be not be good for their wellbeing.

Scientists have found that in the presence of human tourists, whale sharks (Rhincodon typus) exhibit disturbed behaviour patterns such as fast, zigzag movements associated with fleeing predators.

Based on their findings, published in the journal Scientific Reports, the experts said ecotourism may have a significant impact on foraging and, potentially, reproductive behaviour of whale sharks.

The researchers wrote: “Shark populations globally are facing catastrophic declines.

“Ecotourism has been posited as a potential solution to many of the issues facing shark conservation yet, increasingly, studies suggest that such activity may negatively influence aspects of shark ecology and so further pressure declining populations.”

They added: “We find that ecotourism increases the probability of sharks being in a disturbed behavioural state, likely increasing energetic expenditure and potentially leading to downstream ecological effects.”

It is estimated that the global shark diving industry generates more than 300 million US dollars per year.

Joel Gayford, an evolutionary biologist at Imperial College London, and his colleagues believe the potential impacts of shark tourism are still poorly understood.

For the study, the researchers analysed 39 overhead videos of whale sharks in the Bay of La Paz, Mexico.

Their aim was to assess whether shark behaviour changed in the presence of a swimmer mimicking tourist behaviour compared with the sharks swimming in isolation.

The researchers said they observed an increase in disturbed behaviour patterns when the swimmer was present – resulting in the sharks expending more energy than when swimming in isolation.

The team believe this behaviour could make it harder for the whale sharks to hunt for food, and speculate it may even possibly affect reproductive success.

Based on their findings, the researchers suggest tourism operators should be encouraged to assess the behaviour of each shark before allowing swimmers into the water.

They also said that the minimum regulated distance between sharks and tourists – which is around three metres in some places – should also be reviewed.

The team wrote: “In particular, we suggest that sharks engaging in rapid, angular movements should be avoided.”