Document ID: chunk:federal_register_of_legislation:F2016L00300:body:0:p13
Version: federal_register_of_legislation:F2016L00300
Segment Type: other
Provision Reference: 
Character Range: 35795–38920

locations along the eastern and southern coasts of Tasmania, including the lower D'Entrecasteaux Channel, the Acteaon Islands, the Forestier and Tasman Peninsulas, Bicheno and Cox Bight in south-west Tasmania.

* known to occur consists of all locations where the species have been sighted within the past decade, this includes biologically important areas where the species are known to breed, feed or forage.
* likely to occur consists of areas where the species or species' habitat is likely to occur, such as locations adjacent to known distribution polygons or locations where the species have been previously sighted.
* may occur consists of areas where the species or species' habitat may occur, such as historic locations and larger stretches of the coastline within the depth distribution of the species.

Figure 1: Modelled distribution of spotted handfish (Brachionichthys hirsutus).
Figure 2: Modelled distribution of red handfish (Thymichthys politus).
Figure 3: Modelled distribution of Ziebell's handfish (Brachiopsilus ziebelli).

4 Threats

4.1 Historical causes of decline
Declines in the abundance of handfish during the 1900s may be a result of a number of factors, including commercial and recreational dredging and land management activities that caused shifts in turbidity, water and sediment quality. Scallop dredging previously occurred in the D'Entrecasteaux Channel and Great Oyster Bay, with these areas intensely harvested during the 1960s to the 1980s (Last and Gledhill, 2009). These fishing practices are known to have significant impacts on benthic habitat and are effective at catching small, slow-moving benthic fish (Bruce et al., 1999). Dredging may have significantly impacted spotted handfish reproduction and survival by decreasing the availability of important habitat, particularly critical spawning substrate (Bruce et al., 1999; DPIWE, 2002).

4.2 Current threatening processes
Key threats to handfish species covered by this plan include: loss/degradation of habitat, particularly spawning substrate; pollution and siltation of waterways from both diffuse and point-source activities; traditional boat moorings; and the spread of invasive Northern Pacific seastars (Asterias amurensis). Other possible threats to handfish include: fishing; direct predation; illegal collection for the aquaria trade; bioaccumulation of heavy metals; and climate change.
Furthermore, the three species of handfish all exhibit the shared features of small population sizes, highly fragmented distributions and low dispersal abilities (DotE, 2014). Given these factors all three species face an increased risk of localised extinction as a result of stochastic events and are susceptible to a loss of genetic variation.

4.2.1 Habitat degradation and loss of spawning substrate
The principle threat to handfish appears to be reduced abundance and distribution of benthic organisms suitable for egg mass attachment (DPIWE, 2002). This reduction in the availability of suitable spawning substrate was found to limit the reproductive success of spotted handfish in the Derwent Estuary (DPIWE, 2002). All