Divers in Tasmania have found a new population of what is believed to be the world’s rarest fish.
Known for walking on the sea bed, Red Handfish (Thymichthys politus), were previously only found in a 50m by 20m long reef in Frederick Henry Bay near Hobart in south-east Tasmania, with a single population of just 20-40 of the species identified.
Seven divers confirmed the second site – a nearby similar sized reef – which is estimated to be home to the same number of fish.
The divers from the University of Tasmania’s Institute for Marine & Antarctic Studies (IMAS) and the citizen-science project Reef Life Survey (RLS), spent two days searching the reef after a member of the public reported seeing a Red Handfish in the area.
“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,” IMAS Technical Officer Antonia 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.
“Finding a new population that is definitely distinct from the existing one is very exciting. It means there’s potentially a bigger gene-pool, and also that there are potentially other populations out there that we’ve yet to find,” she added.
Check out Antonia Cooper and Rick Stuart-Smith describing their find in the video below.
Rick Stuart-Smith, a University of Tasmania researcher with the Institute for Marine and Antarctic Studies, co-founded Reef Life Survey in 2007 with Professor Graham Edgar to collect data on global marine life. He said eight individuals in the new group were identified, and that this could offer hope that there might be other undiscovered populations out there.
“Finding this second population is a huge relief as it effectively doubles how many we think are left on the planet,” Dr Stuart-Smith said.
Yet the researcher, who coordinates the annual survey project, stated that new populations were likely to be ‘genetically isolated’ because Red Handfish aren’t designed for long distance swims.
“If they are disturbed they can do a little burst, they will swim 50cm in a burst and then settle again,” he told Guardian Australia. “They waddle on their fins, they are just trudging along the bottom. In fact you hardly ever see them actually moving.
“Imagine something that’s seven or nine centimetres long trying to walk 1km on a rocky ocean bottom… they are sitting ducks, plus it’s just a big effort for them.”
According to The Guardian, ‘There are three species of critically endangered Handfish endemic to Tasmania. The Red Handfish is the rarest of those still that can still be found in the wild.’
The future could be looking up for these odd little fish, as Stuart-Smith said researchers would ‘review the viability of a captive breeding program for Red Handfish now that the known wild population was large enough to cope with the capture of a few breeding pairs.’
Image © Antonia Cooper via University of Tasmania.