The nearly 30,000 varieties of the world's bony fish comprise a fantastic medley of shapes and sizes. But if you wanted just about the exact opposite of a big, strong, streamlined, pelagic sort such as the black marlin or bluefin tuna ... well, look no further than the spotted handfish.

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Oh, hai. Image: John Turnbull/Flickr

This blocky, bottom-dwelling, invertebrate-eating peewee looks freshly hatched out of a dragon's egg, or like some mutant pollywog. Its pectoral and pelvic fins have evolved to function more like feet, allowing the handfish to literally stroll around the seafloor. A dorsal fin wedged unconventionally far forward gives the creature a dinosaurian-looking head crest (or a mohawk, depending on your perspective). Throw in a snazzy outfit of spots and a perpetually pissed-off face ("the sour expression of a British bulldog", as The Guardian recently put it) and you've got one charismatic little oddball, decidedly un-streamlined.

There are 13 other described handfishes, pseudo-quadrupedal members of the anglerfish order found only in Australian waters. Like most of those relatives, the spotted handfish is endemic to Tasmania: it trundles the sandy floor of the River Derwent's estuary in the island's southeast, as well as a few of its component bays. Sadly, the past few decades have seen the numbers of this naturally restricted but once-common Tassie native plunge – so significantly that, in 1996, it became the first marine fish listed as "critically endangered" by the Australian government.

The triggers of the handfish's decline are not completely understood, though scientists have some culprits in mind: there's the spread of the exotic Northern Pacific seastar – which may chow down both on handfish egg masses and the sea squirts and other sedentary organisms the fish deposit those masses upon – as well as increased sedimentation in the Derwent estuary due to human land-use practices.

Now, a captive-breeding program is nourishing hope that the spotted handfish won't follow some of Tasmania's other unique creatures – among them, of course, the thylacine ("Tasmanian tiger"), a sort of patron saint of species vanished in the modern era – down the gloomy track of extinction.


 

That initiative, launched in the Tasmanian capital of Hobart by Australia's national science research agency CSIRO, is kicking off with a bang. Two adult handfish – say hello to Harley and Rose! – were captured this month in the River Derwent, and placed in a naturalistic tank right along the Hobart waterfront. The romance was almost instantaneous.

"We had such a beautiful transfer […] that in ten minutes they were exhibiting courtship behaviour in the tank, so they really didn't know they'd come out of the river," CSIRO's Dr Tim Lynch told ABC Radio Hobart.

According to The Guardian, managers of the CSIRO programme hope such successes will allow them to expand the captive reserve of spotted handfish to Tasmania's Seahorse World and the SEA LIFE Melbourne Aquarium (supporters, along with the Zoo and Aquarium Association and the National Environmental Science Programme, of the captive-breeding project).

Besides boosting handfish numbers and scientific knowledge, these "ambassador populations" will help raise awareness about the tiny benthic fish – rarely seen in its wild haunts by the general public, but boasting undeniable appeal when appreciated up-close.

The captive-breeding programme dovetails with continuing efforts to help free-swimming (read: free-walking) spotted handfish by priming the River Derwent with artificial spawning habitat – which will hopefully compensate for breeding substrate lost to rapacious seastars or the scraping of mooring chains. The handfish aren't too choosy about spawning sites, as long as they're elevated off the seabed: besides the plastic sticks deliberately placed in the estuary, they've been known to happily lay eggs amid the waterway's ample litter of beer bottles.

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Top header image: John Turnbull/Flickr