Document ID: chunk:federal_register_of_legislation:F2024L00930:reg:2:p8
Version: federal_register_of_legislation:F2024L00930
Segment Type: reg
Provision Reference: reg 2 (pt 8/48)
Character Range: 83726–86606

by factors such as climate change (Pirzl 2008)Pirzl et al. 2009).

     2.4.3      Mortality and survivorship
Reliable estimates of mortality rates are generally unknown for Australian southern right whales, although concerted effort to compile stranding records in South Australia has been undertaken, revealing cases of known entanglements (Segawa & Kemper 2015) is presumed low given their life history traits, lack of reporting of deceased whales, and increase in long-term population trend. Southern right whales have few natural predators, although calves, and possibly adults, may be vulnerable to shark and orca (Orcinus orca) predation, particularly during migration and in high latitudes (Bannister et al. 1996). Bite marks and scars consistent with shark attack have been photographed on animals in Australian waters from all population classes (e.g., males, non-calving females, juveniles, sub-adults). In adults, these appear confined to the flukes and are unlikely to cause death in healthy, mature individuals (Burnell 1999), whereas direct attacks on a sub-adult and an entangled adult whale have been observed. Adult southern right whales rarely strand, but small numbers of calves are found regularly dead or stranded near calving grounds. Neonatal mortality at the Head of Bight has been estimated to be at least 3 percent during the first three months of life (Burnell 1999).

2.5         Species bioacoustics
All species of right whales are known to produce a range of low frequency vocalisations, with most concentrated at energies below 1 kHz. They produce vocalisations with a fundamental frequency range of 50 to 500 Hz, modelled hearing range between 10 Hz to 22 kHz (functional range of 15 Hz to 18 kHz), and source levels ranging from 132 to 192 decibels (Parks & Tyack 2005, Parks et al. 2007). Vocalisations have been categorised in various ways, although they can be grouped into tonal (including the upcall, downcall and constant call) and broadband pulsive (including hybrid) vocalisations (Clark 1982, Webster et al. 2016, Ward 2020). The vocalisation types and call rate produced by individual whales can be highly variable, depending on individual or group behaviour and age/sex composition of groups (Clark 1982, Parks et al. 2011).
The first characterisation of southern right whale vocalisations in Australia was undertaken in established aggregation areas at Point Ann (WA) and Fowlers Bay (SA), which found low detection call rates (Ward 2020). The most well documented vocalisation is the upcall, which is a simple, short duration (0.5 to 1.5 s), low frequency (50 to 300 Hz) tonal sound that increases in frequency toward the end of the sound. The upcall is considered the primary contact call used by both males and females of all age classes of right whale that may relate to the individual identity of a whale (Clark 1982, McCordic et