Spotted handfish (Brachionichthys hirsutus) are one of Derwent estuary’s most iconic creatures. They are a very special fish, not only for their quirky and striking appearance, but also because the vast majority only live within our estuary, and are highly endangered.
Spotted handfish are 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 spotted handfish has overgrown pectoral fins which look like hands, which they use to slowly walk on the sandy sediment where they hunt for small crustaceans and worms. Fewer than 10 colonies exist with the Derwent estuary. Spawning occurs from September to October, during which freshly laid egg masses are attached to substrate living on the sea floor such as sponges, seaweeds and particularly sea tulips (ascidians).
The principle threat to spotted handfish appears to be reduced abundance and distribution of spawning substrate to attach egg masses – particularly the stalked ascidian, which has been heavily preyed upon by the invasive northern Pacific seastar. In the absence of spawning substrate, eggs laid by spotted handfish are swept away in the current, and 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 2015 Recovery Plan for Three Handfish species outline a number of priority actions to address key threatening processes.
Since 1996, management actions 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. The DEP has previously received several Australian Government grants to support this work, and is currently working with local yacht clubs and NRM South to promote the use of eco-moorings in areas with spotted handfish colonies, as traditional chain moorings tear up handfish habitat and dislodge their eggs, The CSIRO is also currently undertaking additional surveys and research, supported by the Australian Government’s National Environmental Science Program.
You can find out more about spotted handfish ecology and management by following the links below.
- Fishes of Australia: spotted handfish page (including videos)
- National Recovery Plan for Three Handfish species (2015)
- Monitoring of spotted handfish populations and on ground conservation actions (CSIRO, 2017)
- Darlings of the Derwent (CSIRO spotted handfish blog)
- Find out how the timing of maintaining boat moorings can help the spotted handfish
- Helping handfish – Newspapers In Education, The Mercury March 2011