Australasian Science: Australia's authority on science since 1938

New Fish Species Show Their Hand

The pink handfish is one of nine newly described handfish species.

The pink handfish is one of nine newly described handfish species. It has not been sighted since 1999.

By Stephen Luntz

Nine new species of handfish have been found, bringing to 14 the number of known species of one of the world’s most remarkable creatures. Yet specimens of several species are rare, and at least one species may well be extinct.

Handfish get their name from their fins, which have evolved to look remarkably like hands. Although they can swim, they usually prefer to walk along the bottom of estuaries and the seafloor on these fins.

Over the years many specimens have been collected, but until recently most had not been identified to the level of species.

When Mr Daniel Gledhill and Dr Peter Last from CSIRO’s Wealth from Oceans Flagship came to categorise these specimens they nearly tripled the number of species, but the diversity explosion may not last long. Even among the previously known species, the spotted handfish is considered endangered (AS, Feb 1998, p.16) while two other species are listed as vulnerable.

With several of the new species known from less than five specimens, others may be in danger as well, although Gledhill says that deeper water species are less likely to be collected than those that live close to shore.

One species, the smooth handfish, is known from a single specimen found by early French explorers. Gledhill notes that “they collected it with relatively primitive equipment,” and it has not been seen since. Nevertheless he does not give up hope. “Even on land you sometimes have species such as frogs apparently coming back from the dead, and the chances of missing something are multiplied in the marine environment.” Nevertheless, Last says that “several species appear to have very restricted ranges and/or occur in low abundance”.

Fifty million years ago, handfish were found in shallow oceans around the world, but now they are restricted to south-eastern Australia, with six species known from Tasmania alone. Their importance to the local ecosystem is unknown, with no other species known to depend upon them.

A series of surveys took place up to 2007 to assess changes to spotted handfish populations. In some areas the species appears to have vanished, but in other places numbers have fluctuated as a result of unknown causes, which Gledhill suggests may include storms or the introduced Pacific seastar disturbing egg masses and interfering with breeding success, or other unknown factors.