Document ID: chunk:federal_register_of_legislation:F2014L01089:reg:20:p4
Version: federal_register_of_legislation:F2014L01089
Segment Type: reg
Provision Reference: reg 20 (pt 4/33)
Character Range: 10988–13824

estimates put the total east coast population above 1131 individuals, with the highest estimate being 2142 individuals (Bansemer, 2009; Bansemer & Bennett, 2010; Cardno Ecology Lab, 2010). An estimate of approximately 1365 individual grey nurse sharks is considered the most robust estimate currently available for the east coast population (Cardno Ecology Lab, 2010).

Population trends in the west coast population are less well known and estimates of population size have not been made. The primary source of anthropogenic mortality has been from incidental capture by the demersal gillnet fishery that operates between Steep Point, Western Australia and the South Australian border (Chidlow et al., 2006). Analysis of data from this fishery (up to 1997) indicates that the grey nurse shark was relatively abundant in temperate Western Australian waters in the mid to late 1990s (Cavanagh et al., 2003). However, after listing of the species in 1997, catch-rate reporting on this species effectively stopped, making more recent assessments of population size and trends difficult (Chidlow et al., 2006).

    2.3 Aggregation sites – habitat critical to the survival of the grey nurse shark

Grey nurse sharks tend to be found in groups at specific locations (Otway et al., 2003). These locations are known as aggregation sites. Grey nurse sharks are often observed aggregating around inshore rocky reefs or islands. At these locations they are typically found near the sea bed (at depths of 10–40 m) in deep sandy or gravel filled gutters, or in rocky caves (Otway & Burke, 2004; Dicken, 2006; Last & Stevens, 2009). Otway et al., (2003) defined 'key aggregation sites' as being locations where five or more grey nurse sharks were consistently found throughout the year and recommended that these sites be considered habitat critical to the survival of the species. For the purposes of this recovery plan, the Otway et al., (2003) definition of key aggregation sites has been used and, as in the 2002 Recovery Plan for the Grey Nurse Shark (Carcharias taurus) in Australia (EA, 2002), these sites have been considered to be the areas of habitat critical to the survival of the species.

Confirmed key aggregation sites in Australian waters are summarised in Table 1. There are currently four sites identified in Queensland waters, 13 sites located in New South Wales waters and two in Commonwealth waters.

There are also a number of potential key aggregation sites identified in Western Australian waters and potentially further sites in New South Wales waters. These sites require further investigation to confirm if they meet the requirements of five or more grey nurse sharks being consistently found there throughout the year.

Table 1. Known key aggregation sites critical to the survival of the grey nurse shark in Australian