Fish
Spotted Handfish
Brachionichthys hirsutus · also called spotted handfish
The spotted handfish is a small, knobbly, freckled fish that doesn’t swim so much as stroll — walking across the seabed of one Tasmanian estuary on fins shaped like little hands. It was the first marine fish in the world to be listed as Critically Endangered, and it is still hanging on by a thread.
Overview
The spotted handfish is endemic to the lower Derwent Estuary near Hobart, Tasmania — a few square kilometres of shallow, silty seabed. It is a bottom-dweller, picking small worms and crustaceans off and just under the sediment, and it barely moves. It belongs to the anglerfish order, alongside frogfish, and still carries a small stub on its forehead where its ancestors had a fishing lure.
Walking, not swimming
Its pectoral and pelvic fins are modified into stout, jointed, hand-like structures — the pectorals uncannily like a human hand with an elbow and fingers — and it uses them to walk slowly over the bottom. It can only swim in brief, clumsy bursts.
No way to spread
The female lays 80–250 large eggs wrapped around an upright object — a sea squirt, sponge, or seagrass stalk — and guards them for two months. The eggs hatch straight into tiny walking juveniles; there is no drifting larval stage, so the population cannot easily spread or recolonise.
Why it is Critically Endangered
A single small estuary beside a city, no dispersal, specific breeding needs, and then: scallop dredging that tore up the seabed, heavy-metal and sewage pollution, and — decisively — the invasive Northern Pacific seastar, which eats handfish eggs and the sea squirts they lay on. The population crashed, and in 1996 the handfish became the first marine fish ever listed as Critically Endangered.
Saving it
A long recovery effort has planted thousands of artificial “spawning stakes” to replace lost sea squirts, monitors the colonies by diving, maintains a captive insurance population, and works on seastar control and water quality.
Status
Critically Endangered, with perhaps 2,000–3,000 fish. In the same family, the smooth handfish was declared Extinct in 2020 — the first modern marine bony fish confirmed lost.
Spotted Handfish: common questions
Why does the spotted handfish walk instead of swim?
Its pectoral and pelvic fins are modified into stout, jointed, hand-like structures — the pectoral fins in particular look strikingly like a human hand with an "elbow" and "fingers." The handfish uses these to clamber and shuffle slowly across the seabed. It can swim in short, awkward bursts if it has to, but it is a weak swimmer and spends almost all its time on or near the bottom, walking short distances between feeding and resting spots. This lifestyle, shared with its relatives the frogfish and the deep-sea anglerfish, works well for an ambush-oriented bottom-dweller but is a serious handicap when it comes to recolonising areas or escaping a localised threat.
Why is the spotted handfish so endangered?
Almost everything about its biology works against it. It lives in a single small estuary right next to a city (Hobart), it does not swim or disperse, its eggs develop directly into tiny walking juveniles with no drifting larval stage to spread the population, and females need particular objects to lay their eggs on. Then came the damage — historic scallop dredging tore up the seafloor, the estuary was polluted with heavy metals and sewage, and, critically, the invasive Northern Pacific seastar arrived in the 1990s and both preyed on handfish eggs and ate the sea squirts the handfish use as egg-laying sites. The population crashed, and the fish became the poster species for marine extinction risk.
What is being done to save it?
A dedicated recovery programme has been running for decades. Conservationists have installed thousands of small artificial "spawning stakes" — ceramic or plastic stalks planted in the seabed — to replace the lost sea squirts and give females somewhere to lay, and these are readily used. Divers survey the known colonies to track numbers, and a captive breeding "insurance" population is maintained at the Seahorse World facility and partner aquariums in Tasmania, with the aim of eventually releasing young handfish to bolster or re-establish colonies. Control of the invasive seastar and improvement of estuary water quality are also part of the plan.
Are there other handfish species?
Yes — there are about 14 species, all in shallow, cool waters around southern Australia and Tasmania, and the family is one of the most threatened of any marine fish group. Several are Endangered, and the smooth handfish (Sympterichthys unipennis) was declared Extinct in 2020, the first modern marine bony fish confirmed lost. The handfish family's combination of tiny ranges, no dispersal, specific breeding needs, and vulnerable inshore habitat makes it a stark example of how a fish can be driven to extinction as easily as a land animal.