These mesmerising underwater shots show scientists performing ultrasound scans on whale sharks for the first time.
The dedicated researchers had to dive beneath the waves to get close to the 14m long creatures, to perform the examination, similar to ultrasounds carried out on pregnant women.
They say this feat has led them closer than ever before to solving the “mystery” of whale shark reproduction.
Jonathan R. Green, the expedition leader and founder of the Galapagos Whale Shark Project, said: “Almost nothing is known about the reproduction of these giant sharks. After I first saw these huge female whale sharks in the far north Galapagos, I realised that this was a great opportunity to learn more.”
First underwater ultrasound on whale sharks - In pictures
Academics completed the examinations and took blood samples from the creatures in the water off of Darwin Island, Galapagos.
The remote island, part of Ecuador and in the Pacific Ocean, is one of the only places where female whale sharks can be seen most years.
Their results allowed them to see and identify reproductive organs.
They also managed to identify developing follicles inside the animals.
Members of the team conducted scans using a 17 kg ultrasound system in a waterproofed case.
One scientist and diver involved, Dr Rui Matsumoto from the Okinawa Churashima Foundation in Japan, had to use a propeller system mounted on an air-tank to keep up with the sharks.
“We use some interesting technology anyway, but working with the Okinawa team was something else,” said Dr Simon Pierce, an expedition member from the Marine Megafauna Foundation.
“I felt cool by association. We saw dive groups a couple of times at the site, and I can only imagine what they thought – why is that guy diving with a briefcase? And a jetpack?”
Dr Matsumoto described the results the teams discovered as “promising” and it set them in a strong position for further research.
Dr Green added: “These big female sharks are not going to give up their secrets easily. One thing is clear: there’s a lot of work still to do to understand the reproductive processes of this endangered species.”
This two week expedition was a joint venture between Galapagos Whale Shark Project, Galapagos National Park, Okinawa Churashima Foundation, University of San Francisco/Galapagos Science Center and the Marine Megafauna Foundation.
Whale sharks can live up to 70 years in the wild and weigh on average around 11 tons.
They are the largest known species of fish and are classified as endangered.
Photos and video were provided by Simon J Pierce and Chris Rohner.
