They were moving around the whales’ bodies with surprising agility and attaching and reattaching when the whales breached for air.
Researchers have dubbed the ride the “remora roller coaster”.
“They photobombed us,” Meynecke said, adding that his cameras had captured the remoras in increasing numbers in the past two years.
“In previous years, we have seen one passing by, but now we’ve had 20 or so just in front of the camera, and it really triggered us to look into this further,” he said.
Some of the footage showed up to 50 remoras on a humpback - with whales that shed more skin attracting more of the fish, Meynecke said.
Remoras are a family of species that are known for their ability to grip onto whales, manta rays, or sharks - and have been known to attach themselves to boats and scuba divers, according to Griffith University.
They live around five years on average and can range in length from 30 to 90cm.
Meynecke said remoras look a bit like an “upside-down fish” as their gills have a suction system that allows them to hold on to their host.
Some species, such as the “whale-sucker” (remora australis), prefer whales as a host, but they have also been seen riding turtles, sharks, and dugongs.
“They look very strange to us, but the benefit to them is that if they do find a host … they don’t have to swim, the other animal does it for them,” Meynecke said.
The symbiotic relationship is believed to be mutually beneficial, with the remora eating small crustaceans and sea lice that live on the whale’s skin, helping to keep it clean.
The footage of the rides also shows the remoras nibbling on the whale’s skin for the first time, Meynecke said.
“We don’t know that they’re actually digesting it, but it was clearly taking it into its mouth,” he said about one particular fish caught on camera, adding that the common consensus until now has been that remoras eat the sea lice and crustaceans attached to the whale, not the whale itself.
“I would love to capture one and find out what kind of diet they have. What’s the percentage of whale skin or whale-related DNA they have inside them? But they’re not easy to capture,” he said.
The Queensland-based scientist is interested in studying whether there is a relationship between the humpback migration season, whales shedding their skin, and the remora population.
While his video footage showed a greater number of remoras per whale in the past two years, he cautioned that it was not possible to tell whether the remora population was increasing as a whole.
A rise in numbers could also be due to growth in the humpback population around Australia, he added.
Humpbacks typically travel between 15 and 18km/h, and the footage showed the remoras moving around the whale’s body to find a resting place with the least resistance from ocean currents, Meynecke said.
He added that while the fish could be seen on all parts of the whale’s body - even hanging off the tail - the “preferred spot” appeared to be the soft underbelly.
The insights also raise questions about the life cycle of remoras generally, including how they find a whale to attach to and whether they follow the whales during an entire migration, which can take humpbacks from Antarctica to northern Australia.
“If they do let go at some point, where do they go?” Meynecke asked.
He added that while the relationship appears largely beneficial to both parties, the footage has also led to speculation that the whales may get fed up with their passengers.
Some whales with more than 50 fish attached could be seen repeatedly breaching the water and then eyeballing the fish, as if “checking” to see if they had managed to shake them off, Meynecke said.
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