Out of hot water
Critically Endangered red handfish removed from the wild to safeguard the species from extinction
Twenty five red handfish – a Critically Endangered species of anglerfish – have been taken into care by scientists at the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania. The relocation, carried out with permission from the Australian government to protect the species against predicted marine heatwaves, has decreased the wild red handfish population from approximately 100 to just 75 individuals.
Unlike other fish, red handfish don’t have a swim bladder to control their buoyancy. Instead, they use their large, hand-like fins to ‘walk’ along the seafloor. These peculiar creatures are around 8cm long – smaller than a playing card – and pink, red or brown in colour with a ‘grumpy’, downturned mouth. “If you’ve never seen a handfish before, imagine dipping a toad in some brightly coloured paint, telling it a sad story and forcing it to wear gloves two sizes too big,” says the Handfish Conservation Project website.
One of 14 handfish species, all of which are found off southern Australia, predominantly Tasmania, the red handfish is thought to be one of the rarest marine fish in the world. It is restricted to two small areas of rocky reef southeast of Hobart, and is buffeted by threats such as boat traffic, anchoring, urban development, pollution and nutrient run-off, as well as habitat degradation (by overgrazing of native sea urchins) and the impacts of climate change.
Walking along the seabed instead of swimming means these diminutive fish can’t travel very far to escape these threats. Neither do they have a larval stage when young, so they cannot drift through the ocean to colonise new areas.
Add predicted marine heatwaves to the picture and the outcome could be bleak. “We can only assume that this additional stressor will impact the already fragile population,” says IMAS researcher Jemina Stuart-Smith, who co-leads its red handfish research and conservation programme.
“This strategy certainly isn’t without risk, but the handfish relocation from sea to aquariums was quite seamless, and they have settled into their new homes very nicely,” says Andrew Trotter, who leads IMAS’s conservation breeding project for red handfish.
The team hopes to return the individuals to the wild in the winter, provided their habitat is suitable. Until then, the focus is on restoration and management while the 25 individuals are kept safe in the aquariums. “We don’t want to keep them any longer than necessary,” says Trotter. “They’re wild animals and belong in the sea.”