Spotted handfish (Brachionichthys hirsutus) are one of Derwent estuaries most popular creatures. They are a very special fish, not only for their quirky and striking appearance, but also because they only live within our estuary, and are highly endangered.
The spotted handfish has overgrown pectoral fins which look like hands. They use these fins to slowly walk on the sandy sediment where they hunt for small crustaceans and worms. Fewer than 10 colonies exist with the Derwent estuary. Breeding involves attaching freshly laid egg masses to substrate living on the sea floor such as sponges, seaweeds and ascidians. Spotted handfish are very small, only growing to a maximum size of 12 cm, meaning they could fit within the palm of your hand. Each fish is covered with spots or stripes, in patterns unique to each individual.
The principle threat to spotted handfish appears to be reduced abundance and distribution of spawning substrate to attach egg masses. In the absence of spawning substrate eggs laid by spotted handfish are swept away in the current. Females cannot effectively guard their egg masses to ensure that they hatch successfully. Poor recruitment of young fish will lead to the eventual extinction of colonies. Due to the speed of their decline in range and abundance the spotted handfish became the first marine fish to be listed as endangered under the Federal Environment Protection and Biodiversity Protection Act 1999, and was followed by state protection under Tasmania's Threatened Species Protection Act 1995. The Spotted handfish Recovery Plan 1999-2001, and the Recovery Plan for four species of handfish outline priority actions for key threatening processes.
Since 1996, management actions in accordance with recovery plans have included: the collection of baseline biological data; examination of habitat requirements; development of techniques to assess population size and stability; monitoring of known colonies; surveys of new potential habitat; development of artificial spawning substrate; and, the establishment of captive husbandry protocols. A grant awarded to the DEP by the Federal Governments Caring for Our Country program is supporting additional surveys and the plant out of artificial substrate to replace lost breeding habitat.
Photo: Rick Stuart-Smith
Restoring and promoting the Derwent estuary