Document ID: chunk:federal_register_of_legislation:F2024L00930:reg:2:p5
Version: federal_register_of_legislation:F2024L00930
Segment Type: reg
Provision Reference: reg 2 (pt 5/48)
Character Range: 75804–78766

memory' of calving areas, which may explain the slow rate of recovery in the Australian south-east region (Carroll et al. 2015). Southern right whales were only rediscovered in Australia in 1955, with anecdotal reports of a small number of whales occurring up until 1970 (Chittleborough 1956, Bannister 1986) followed by increases in numbers from the 1980's. The intense over-exploitation of right whales has shaped their current population structure, demographic parameters, and rates of recovery in the two different populations across their range (Harcourt et al. 2019).

2.4         Biological information

    2.4.1     Morphology and physical characteristics
Southern right whales are large baleen whales of rotund body shape and are recognised by the lack of a dorsal fin, broad and short pectoral fins and distinct skin growth on their heads and lower jaw called callosities (Figure 1). They use baleen plates made of keratin (a protein) as a sieve to filter water through to feed on their prey. Southern right whales reach a maximum length of approximately 16 m, with contemporary body length data from Head of the Bight suggesting southern right whale females (lactating females) range between 13.0 and 14.9 m (mean = 14.2 m) and between 11.1 and 16.2 m for southern right whales including data from Argentina (Christiansen et al. 2018, Christiansen et al. 2022). Mature females are slightly larger than males and southern right whales slightly smaller than Northern Hemisphere Right Whales (Tormosov et al. 1998, Jefferson et al. 2015). With a predicted weight of around 40 tonne, they are heavier than other baleen whales of a similar length and their bulky body form is markedly different from the more streamlined balaenopterid whales (Jefferson et al. 2015, Christiansen et al. 2019).

Southern right whale callosities are patches of keratinised skin colonised by cyamids (i.e., small crustaceans), that provide unique markings on the dorsal surface of the rostrum, the lip line of the lower jaw, and just posterior to the blowhole that are present from birth and persist throughout their life (Payne et al. 1983). Given their uniqueness and persistence, callosity patches (Figure 2) form the basis of long-term identification and monitoring of individuals using methods such as photo-identification. This ability to identify individuals allows for estimation of life history parameters (e.g., calving intervals, age of sexual maturity, survival, and mortality), assessment of movement patterns, residency and site fidelity, and investigation into correlations between environmental and climatological variations on reproductive rates and trends in abundance.

    2.4.2     Demographics and reproduction
Gestation in southern right whales is thought to be approximately 11 - 12 months (Burnell 2001), lactation lasts at least 7 – 8 months (Tormosov et al. 1998), with weaning occurring within 12 months (Lockyer 1984). The apparent age at first