Marine scientists have formed a symbiotic relationship with whale sharks in the Ningaloo area in Western Australia as they exchange parasite removal for research data.
Key points:
- Sampling parasitic crustaceans could replace the need for taking pieces of whale shark skin for research
- Some whale sharks will stop in the water and allow parasite removal by scientists who act like giant cleaner fish
- Anyone who swims with a whale shark should never attempt to touch them
Usually remoras, otherwise known as suckerfish, would take care of parasitic crustaceans on whale sharks, but they can only do it for flat surfaces as opposed the mouth and leading edge of a shark's fins.
But researchers have found that some whale sharks will stop swimming and allow them to scrape copepods from tricky to clean areas like the lips with plastic knives.
A new paper from the University of Western Australia and published in the international journal Fishes suggests researchers could find out the same information about what the sharks eat from the copepod samples as they would from the more invasive process of taking pieces of skin.
Adjunct senior research fellow Mark Meekan, who co-authored the research while at the Australian Institute of Marine Science, said traditionally chemical hints were taken from tissue samples of whale sharks to find out how deep they were when eating in the ocean and determine what they might be feeding on.
"We can see how far up the food chain that whale shark is feeding and also where its carbon is coming from," he said.
"Now it turns out that the copepods are actually like a little black box flight recorder for the whale shark.
"Rather than taking the skin of the whale shark, if you take the copepod it's full of whale shark tissue."
The data collected will help further unravel the mysteries of the mysterious fish with so many unknowns still about where it reproduces.
And there are still questions about where the mostly juvenile whale shark males which visit Ningaloo go when they get older.
Like 'the biggest cleaner fish'
The relationship between man and world's largest fish did not happen overnight at Ningaloo.
They may look slow in the water but it takes a lot of effort to keep up with the whale sharks, let alone get up to its head and start to collect copepods while holding your breath.
Dr Meekan and others have been collecting copepods from whale sharks for about 10 years, but it was only more recently some would stop for a cleaning.
"As it turns out the whale sharks actually don't mind the procedure at all," he said.
"In fact, some of them even slow down and stop and will actually let me get up the front of them and scrape lots of parasites off.
"I think that whale sharks probably look at me and go 'what on earth is that inelegant, poorly swimming thing', and when I start scraping the copepods off the lips, like, 'oh my god, it's the biggest cleaner fish I've ever seen'."
First rule of whale shark club
Marine scientists who work around Exmouth have gone through years of government permit applications and university ethics committee deliberations to be allowed to scrape off whale shark parasites.
The scientific practice was recently caught on camera for the new ABC documentary series Ningaloo Nyinggulu, but visitors to the region are being urged to follow Australian guidelines to not touch or swim too close to the whale sharks.
WA's Department of Biodiversity, Conservation and Attractions licences commercial operators to run whale shark swimming tours and also publishes a guideline on best standard practices for how to interact with them.
In 2022 about 36,000 people swam with the Ningaloo whale sharks through tours.
Under the guidelines there is an approach zone for boats of 250 metres from a whale shark, and they must never get closer than 30 metres to an animal.
Swimmers must never attempt to touch or ride on a whale shark, or get closer than three metres from its head or body.
They must also stay at least four metres away from its powerful tail.
Dr Meekan said a whale shark could weigh several tonnes so it was not a creature you wanted to annoy.
"If you're out there just swimming with a whale shark the golden rule is don't touch it, and they say don't touch it for a very good reason," he said.
For more on this story watch Ningaloo Nyinggulu which premieres Tuesday, May 16 at 8:30pm on ABC TV and ABC iview.