Though related to the leafy and common seadragon, ruby seadragons are so elusive that capturing them on video in the wild has proved impossible – until now.
A team of researchers has achieved what seemed an impossible task: filming a pair ruby seadragons swimming together off Western Australia’s Recherche Archipelago.
The footage is a result of a year-long investigation by Scripps Institution of Oceanography, which is based at the University of California, and Western Australian Museum.
Last year, marine biologists from the two institutions described the ruby seadragon for the first time, essentially recategorising old specimens of misidentified common seadragons.
With the new species on the list, they went out searching for living evidence. This was important due to the ruby seadragon’s odd lack of elaborate appendages, something they established through 3D models of the discovery.
On the hunt for a few days, the team struck ruby gold 50m below the surface, spotting a pair of the elusive creatures. Filming them for half an hour, the footage fills in plenty of gaps for scientists.
Notably, the seadragons didn’t have camouflage-friendly appendages, and therefore, how they looked and swam was telling.
“It was really quite an amazing moment,” said Scripps graduate student Josefin Stiller, co-author of the study. “It never occurred to me that a seadragon could lack appendages because they are characterised by their beautiful camouflage leaves.”
The team also found out that ruby seadragons have a curled tail, distinct from common or leafy seadragons, the other two types known in nature. This makes them look far more like seahorses.
During the filming, the team learned that the species’ eating technique is aided by a striking technique – though what they ate was a surprise. The fish’s habitat lacks kelp and seagrass, but instead is dominated by sponges, once considered an undesirable habitat for seadragons.
“There are so many discoveries still awaiting us in southern Australia,” said Scripps’s Greg Wilson, a co-author of the study. “Western Australia has such a diverse range of habitats, and each one is deserving of attention.”
“Until last year, no one had ever suspected a third species of seadragon existed,” said Nerida Wilson of the Western Australian Museum, lead author of the study and curator of the Scripps Benthic Invertebrate Collection.
“This discovery was made thanks to the great benefit of museum collections.”