Right on our doorstep, in the Derwent Estuary, lives a fish that can walk not on the water, but on the sea floor. These unique little ‘walking’ fish were once plentiful in the coastal waters around southern Tasmania. Now there is only a handful of them left in the bays adjoining Hobart. In fact, their numbers have declined to such an extent that, in 1996, they were declared an endangered species – as the first Australian marine species to be threatened with extinction. more...
Spotted handfish (Brachionichthys hirsutus) are small, often strikingly patterned or colourful, sedentary fish that tend to ‘walk’ on the seabed on hand-like fins, rather than swim. Handfish prefer a sandy sea floor, and are inclined to stay in the same area rather than disperse. This is because they do not have a larval stage but hatch from the egg as fully formed miniature handfish. This makes them particularly vulnerable to threats such as siltation and heavy metal contamination.
Their habit of sitting still on the sea floor, and laying egg masses on sea tulips (ascidians), also makes them particularly susceptible to predators. The introduced northern Pacific seastar arrived in the thousands several decades ago – about the time the handfish began to decrease – and is one of the main culprits in the decline of the population. The seastar eats not only the sea tulips that the handfish lays its eggs on, but the eggs, too.
It is important to preserve the spotted handfish, not only as a unique part of our local marine life but also because, as Dr Peter Last of the CSIRO explains, “They are of great importance to understanding the origins of Australian marine life, the role of Australia as a refuge during previous periods of change, and the effects on living species of habitat alteration and rapid climate change.”
^ less