FOUND ONLY IN Australian waters, handfishes have stood out as oddities ever since French mariner Nicolas Baudin wrote in 1802 of a fish in Tasmanian waters whose "foremost fins are exactly like hands".
They come in strange colours and shapes. The red handfish (Thymichthys politus) is blood red and the cockatoo handfish (Pezichthys amplispinus) has a fin like a feathered crest. Handfishes are like anglerfish in having an illicium, a spine like a fishing rod with a lure on top to attract prey close to their big mouth. Too slow to chase prey, handfish need it to come to them.
Much about these little fishes remains mysterious. Despite many surveys the smooth handfish (Sympterichthys unipennis) is known only from one faded specimen caught in ‘southern Australia’ on Baudin’s expedition more than 200 years ago. The eyelash handfish (Pezichthys nigrocilium) only came to light in 2004 when one was retrieved from an underwater canyon just west of Tasmania. It too is only known from one individual, and so is the longfin handfish (Pezichthys macropinnis), discovered in 2000 well west of Ceduna in South Australia. Several of the 14 species were not named until 2009 and more are believed to await discovery.
Red handfish (Thymichthys politus) (Image: CSIRO)
Very small distributions help make handfishes unusual. Many marine fishes occur widely because sea currents carry them about. Tropical species such as Moorish idols and parrotfishes turn up in Sydney Harbour although the winters kill them. Some of the fishes on the Great Barrier Reef have ranges that extend from Africa to Hawaii.
Of the 14 handfish species, seven are only known from Tasmanian waters. The Australian spotted handfish (Brachionichthys australis), found from southern Queensland to the Great Australian Bight, is the only one that is wide-ranging.
Handfishes lack mobility because even when newly born they don’t swim or ride currents. The seas of temperate Australia are their only home, but fossil relatives have turned up in Italy. More than 40 million years old, these show that handfishes may once have waddled about almost everywhere. Australia is where they have survived but probably not where the family originated.
Because handfishes lack mobility they are at risk of declining even more. The spotted handfish (Brachionichthys hirsutus) has shown this by becoming the first Australian fish declared endangered. Once found more widely in Tasmania, it is now almost confined to Hobart’s Derwent Estuary and nearby bays.
In Hobart I have walked from the Salamanca Markets to the harbour edge a minute away to look down on giant orange starfish in the water. These Northern Pacific seastars (Asterias amurensis), accidentally introduced from northern Asia with shipping, eat the sea squirts on which the spotted handfish lays its eggs. Introduced crabs may be eating its eggs, and siltation in the estuary could be another problem. So could past dredging for scallops in Tasmania’s bays. The red handfish and Ziebell’s handfish are also vulnerable to extinction. Australia is the last refuge for handfishes, but we can’t pretend they are safe here. If they are to keep waddling about and luring prey their way, we need to manage our coastal waters well.
Tim Low is the author of the award-winning book Where Song Began. Follow him on Twitter @TimLow5.