Projects

Are artificial spawning substrates the key to enhancing populations of the endangered Spotted Handfish in the Derwent estuary?

Supervisor team may include:

Dr Neville Barrett
Tim Lynch (CSIRO)
Mark Green (CSIRO)

The spotted handfish is one of only a few Australian fish species listed as highly endangered under the EPBC act. The species is primarily only found in the Derwent Estuary, with a life history (site-attached adults producing guarded egg masses that hatch as miniature adults with no dispersal phase) that restricts their capacity to move in response to a changing environment. There are multiple threats to this species, including a physically degraded environment within the river and an increasing abundance of introduced pest species that may compete for resources and modify habitats. Previous studies have suggested that predation on stalked ascidians by the introduced seastar Asterais amurensis may be particularly problematic for the handfish as they preferentially use the ascidians as substrates for deposition of egg masses. Certainly the short egg mass stage (up to six weeks) may be the most critical stage in  their life history. As a management response to this, artificial spawning substrates have been developed and planted out at known handfish 'hotspots" throughout the Derwent estuary.  Brief surveys of these substrates suggest they are indeed utilised by the handfish, although the extent that they are utilised in preference to other natural substrates has yet to be determined, nor has the likely survival of eggs on such substrates during the incubation period. A potential Honours project would examine the success of artificial substrates at a range of sites throughout the estuary relative to natural substrates, and document the overall survival of egg masses over this period and the types of threats that they are exposed to, (e.g. predation by seastars, fish, crabs etc) and the methods that guarding adults may use to prevent egg loss. It would utilise a range of technologies such as underwater GPS (to relocate each spawning substrate with eggs) and time-lapse GOPRO cameras.  This project is supported by the Derwent Estuary Program (DPIPWE) with a $2000 grant towards operating expenses of a dive-based research program, and with supervisory support from the Spotted Handfish advisory team, including representatives from IMAS, CSIRO and the Derwent Estuary Program.

Suitable for February or July start date.

Contact Dr Neville Barrett (neville.barrett@utas.edu.au) for more details.

Authorised by the Executive Director, Institute for Marine and Antarctic Studies
October 7, 2019