New population of red handfish, world's rarest fish, found in Australia

Jan. 25 (UPI) -- Scientists in Australia have discovered a new population of red handfish, thought to be the world's rarest fish. The new population was found off the coast of Tasmania by divers with the Institute for Marine and Antarctic Studies.

Until now, scientists had identified just a single population of red handfish, Thymichthys politus, living off the southeastern coast of Tasmania. The population featured between 20 and 40 individuals.

The newly discovered population also contains between 20 and 40 fish and was discovered several miles from the original group.

There's no chance the original population relocated. The red handfish doesn't swim. Instead, the fish crawl along the seabed. The two populations were found in areas roughly the size of two tennis courts.

"Finding a new population that is definitely distinct from the existing one is very exciting," IMAS researcher Antonia Cooper said in a news release. "It means there's potentially a bigger gene pool and also that there are potentially other populations out there that we're yet to find, so it's very exciting indeed."

Citizen scientists participating in the Reef Life Survey project first spotted a specimen of the rare species. Scientists followed up on the sighting, but had difficulty locating the rare fish.

"We were diving for approximately three and a half hours and at about the two-hour mark we were all looking at each other thinking this is not looking promising," Cooper said. "My dive partner went to tell the other divers that we were going to start heading in and I was half-heartedly flicking algae around when, lo and behold, I found a red handfish."

Though the size of each population is similar, as is the size of their domains, the seabed in each location is distinct, offering scientists a better understanding of the species' preferences and adaptability.

Tasmania's coastal waters remain a last refuge for several rare species, including the spotted handfish, but researchers worry the Ziebell's handfish, a third species listed as endangered, has all but disappeared.

"The only thing that would have been more exciting last week would have been finding the Ziebell's and finding out that they're not extinct," said Rick Stuart-Smith, IMAS scientists and co-founder of the Reef Life Survey. "Ziebell's handfish hasn't been seen in over a decade, and there is a feeling that it's quite possibly extinct, or at least very close to being so."

Scientists hope their survey efforts will inform new management and conservation plans for handfish and other endangered species.