|Summary||Southern Right Whale (Eubalaena australis) used as a proxy for the impact of MPAs on migratory species. Southern right whales migrate annually through the Great Australian Bight Region during the winter and spring, and the MPA is an important aggregation and calving site. Whaling in the 1700s drastically reduced Southern Right Whale numbers, and although still scarce relative to historical abundance, it is not considered under threat at the hemispheric level and is listed as Least Concern on the IUCN RedList. The most recent population estimate for the Australian population is ~3,500 individuals (Bannister 2010). They are listed as endangered under the threatened species category of the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and as Vulnerable under the South Australian National Parks and Wildlife Act 1972.|
|Subtype||Natural Resource Unit|
|Sector||Marine protected areas|
|Explanation||The southern right whale is 1 of 3 species of large, baleen whales classified as right whales and belonging to the genus Eubalaena. They are closely related to the northern hemisphere right whales but the species are reproductively isolated from one another by the geographic separation of calving grounds and asynchronous breeding seasons (Townsend 1935). Australian southern right whale populations have different mtDNA haplotype frequencies from other southern hemisphere populations although nuclear DNA structuring is low (Baker et al. 1999; Carroll et al. 2011; Patenaude et al. 2007).
Southern right whales in Australian waters comprise two populations, one in the south-west and one in the south-east, both of which are genetically differentiated (based on mtDNA haplotype frequencies) (Carroll et al. 2011). The Australian population is estimated at 3500 individuals with 2900 of those occurring in the south-west region between Cape Leeuwin and Ceduna during breeding season (Bannister et al. 2011), and make up about 83% of the total estimated Australian southern right whale population.
|Commons Boundaries||Somewhat unclear boundaries (2)|
|Explanation||Australian coastal movements are reasonably well understood but little is known of migration travel, non-coastal movements and offshore habitat use. The whales forage and feed offshore in the summer months (from November to April) between at least 32 degrees South and 65 degrees South (Australia 2012) and have been observed as far south as the Antarctic (Bannister et al. 1999). From May to October, the breeding females occupy near-shore coastal calving and nursery areas that occur between 16 degrees South and 52 degrees South (IWC 2001; Werner et al. 2011). |
|Commons Indicator||["Status of highly migratory species"]|
|Explanation||Status of highly migratory species - The whales forage and feed offshore in the summer months (from November to April) between at least 32 degrees South and 65 degrees South (Australia 2012) and have been observed as far south as the Antarctic (Bannister et al. 1999). From May to October, the breeding females occupy near-shore coastal calving and nursery areas that occur between 16 degrees South and 52 degrees South (IWC 2001; Werner et al. 2011). |
|Commons Unit Size||Large (4)|
|Explanation||Southern right whales can reach a maximum length of 17.5 meters and weigh up to 80 tonnes. Females are generally 1 - 2 meters larger than males. |
|Explanation||Calving and non-calving whales are found in the Southern Ocean between 16 degrees South and 65 degrees South in the summer (November to April) and the near shore waters of southern Australia in the winter (May to October). On the Australian coast, southern right whales are known to use widely separated coastal areas (200 - 1500 kilometres apart) within a season (Burnell 2001; Charlton et al. 2014) . |
|Inter Annual Predictability||Moderate (2)|
|Explanation||Females demonstrate high site fidelity, returning to the same calving grounds every 3 - 4 years (Burnell 2001). Females have been shown to alter selected calving habitat in years of high abundance at the Head of Bight (Burnell, 2012). Female on average calve every 3 - 4 years and this triennial calving cycle has resulted in cohort structured breeding groups in Australia, with peaks in abundance of the primary breeding group every 3 years. Annual population or cohort sizes and compositions in Australian waters reflect the 3-4 year calving cycle of females and as a result, full population assessments are only possible from extended time series of population abundance indices.
|Intra Annual Predictability||Moderate (2)|
|Explanation||Southern right whales are a migratory species and the movements of males, non-breeding females and sub-adults are less understood than breeding females. Finding a southern right whale at any one point during the summer months when whale migration is occurring is not guaranteed. However, female whales and their calves are observed frequently from the cliffs at the Head of Bight in the near shore waters of southern Australian during the winter months.|
|Commons Renewability||Renewable (1)|
|Explanation||Renewable but southern right whales are slow to reproduce and have low regeneration rates.|
|Productivity||Poorly productive (1)|
|Explanation||Southern right whales reach sexual maturity at an average of 7 - 8 years of age. Female whales have a gestation period of ~12 months and on average calve every 3 - 4 years. This triennial calving cycle has resulted in cohort structured breeding groups in Australia, with peaks in abundance of the primary breeding group every 3 years. A difference in the calving dynamics at the Head of Bight aggregation, compared to the rest of the south-west population has been reported, with more 4-year inter-calf intervals and fewer 2-year inter-calf intervals recorded than for the wider population (Bannister et al. 2011).
The recovery and re-occupancy rates for the south-western population is estimated to be increasing at ~7% per annum (Bannister et al. 2011), which is near or at maximum population growth. The most recent estimated mean increase in the number of southern right whales at the Head of Bight aggregation; using cliff-top count data is ~5.5% per annum (Charlton et al. 2014).
|Commons Accessibility||Somewhat accessible (2)|
|Explanation||The increase in vessel technology such as radar and GPS make is easier to locate the whales although; most whale watching takes place from land at the Head of Bight cliffs.|
|Commons Heterogeneity||Moderate (2)|
|Explanation||Southern right whales are a migratory species and the pathways of southern right whales between their main foraging grounds in the Southern Ocean and the calving grounds in the Great Australian Bight region are poorly understood. The movements of males, non-breeding females and sub-adults are less understood than breeding females, which return to the same coastal calving beaches every 3 - 4 years. Finding a southern right whale at any one point during the summer months when whale migration is occurring is not guaranteed. However, female whales and their calves are observed frequently from the cliffs at the Head of Bight in the near shore waters of southern Australian during the winter months.|
|Commons Mobility||High (3)|
|Explanation||Southern right whales have a circumpolar distribution between latitudes of 16 degrees South and 65 degrees South. Between May and October the Australian population of southern right whales migrates between higher latitude feeding grounds (between 40 degrees South and 65 degrees South) to calving/nursery grounds in coastal Australian waters. It is thought that in the spring, the southern right whales move offshore from the Great Australian Bight to higher latitude foraging areas and down towards the ice-edge off Antarctica. |
|Commons Spatial Extent||19395 |
|Explanation||This is the approximate spatial extent of the GABMP (Commonwealth Waters) (2012) that this environmental commons uses but Australian populations of the southern right whale move between Antarctica and southern Australia during their seasonal migration.|
|Explanation||There is no technological substitute that can take the place of southern right whales in the GAMP (Commonwealth Waters) from an ecological or economic standpoint. |