A new University of Queensland and Murdoch University study of whale sharks has detected their presence at Ningaloo Reef, off Western Australia, all year round, with many staying close to the reef edge.

Study co-author and UQ graduate Samantha Reynolds said until recently, knowledge of whale shark movements at Ningaloo Reef outside the tourist season had been limited to occasional sightings from citizen scientists recorded in the Wildbook for Whale Sharks photo-identification library.

“The whale shark ecotourism industry typically operates at the Ningaloo Marine Park between March and August each year when the numbers of these giant fish peak,” she said. 

“However, this research, which doesn’t rely on direct observation, used acoustic transmitters to monitor whale sharks.

“It has produced a more accurate picture of whale shark behaviour at Ningaloo Reef and may provide visitors with greater opportunity to swim with whale sharks.”

The researchers fitted electronic tags to 21 whale sharks - 20 of which were juvenile males - and monitored their movements through acoustic receivers located along Ningaloo Reef.

The sharks were monitored for periods of between two and 339 days from September 2011 to July 2013.

Findings showed that some of the whale sharks moved outside the reef for extended periods of time, with one absent for 65 days between visits and another away for 48 days.

Ms Reynolds said the study results complemented recently published satellite-tracking work by some of the same researchers which showed whale sharks making homing movements to Ningaloo Reef, returning to the area outside the recognised tourist season.

These studies present implications for the long-term conservation and management of this endangered species in the area, in particular if the associated ecotourism industry extends the period of operation in line with these new findings.  

“We show that it’s possible to swim with whale sharks at Ningaloo all year round, but ultimately extending the tourism season would depend on tourist numbers and demand, and would be up to the tourism industry and its management agency,” Ms Reynolds said.

“The tourism industry at Ningaloo Reef is considered ‘World’s Best Practice’ and appears to have little or no impact on sharks at present.

“There is no reason to suppose that this would change with an extended tourism season, but to really understand the effects of tourism on whale sharks, further research on their behaviour is crucial.” 

Ms Reynolds said the research was helping to solve some of the mysteries of whale shark movements, and importantly, indicates that Ningaloo Reef is a critical habitat for this endangered species all year round.

The papers have been published in the Journal of Fish Biology (DOI: 10.1111/jfb.13461) and Diversity and Distributions (DOI: 10.1111/ddi.12618).

 

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