Scoop World

Baited Cameras And Submersible With Robotic Arm Surveying Tuvalu Waters

Tuesday, 6 May 2025, 2:56 pm
Article: RNZ

Christina Persico, RNZ Pacific Bulletin Editor

An expedition in Tuvalu's waters is using a submersible to study the ocean - some parts of which have never been studied in-depth.

The National Geographic Pristine Seas project is studying the health of Tuvalu's marine environments. The expedition is a partnership between Pristine Seas and Tuvalu government.

Expedition leader Keiron Fraser said they will be deploying a range of scientific equipment in the sea and the tech will help them get an idea of the health of the ocean in that area.

"The leg we're on at the moment is a deep sea leg. So, a lot of the work that we're doing at the moment is centred around our submersible, the Argonauta, and that's a three-person submersible which is rated to go down to 1300 metres," he said.

"We can put scientists in that with a driver to record scientific observations, count fish, look for species and things like that."

Fraser said the submersible has a variety of tools on it, including a manipulator arm enabling the scientist to reach out and grab things.

It also has capability for a process called environmental DNA, or E-DNA.

"When an organism's floating around in the water or swimming, it releases very, very small fragments of DNA, which is obviously from the bodies and that can be released in a variety of ways.

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"Using those DNA fragments you can actually sequence them.

"So instead of swimming around looking for the fish species that you can see, you can collect water and to some degree you can identify - without seeing the actual organism, from their DNA in the water - the species that lives there."

They also use BRUVs - baited remote underwater videos.

"The idea of these is that you put them in the water and basically they record what species turn up.

"They've got a bait can on them...the various organisms in the area smell the the scent of the bait and come to the cameras and then from that you can work out what species live in that area and to some degree the density of them."

Fraser said the area they are working in is fairly unexplored.

"In some of the shallower waters, there's been some really good work done on scientific diving - shallow water surveys on fish and corals and things, but certainly in the area we're working for the next month in the deep sea, there's been I'm pretty sure next to nothing done.

"The sort of data that we're collecting will help the Tuvalu government and the communities understand what lives in their seas and identify areas which are really prime for protection."

The team will also conduct bird surveys, and after this expedition a second one is planned.

"On that one there'll be scientific diving, looking at fish distributions using a technique called underwater visual census, and species that live on the bottom, such as coral and invertebrates, so things like sea cucumbers."

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