Every winter, endangered southern right whales migrate north from cold Antarctic water to the temperate coastal waters of the Yalata lands for breeding purposes.
The protected Far West Coast Marine Park at the head of the Great Australian Bight is popular with breeding whales because the warm, shallow waters and sandy ocean floor are protected from harsh weather conditions and sea floor structures, such as coral reefs, that are potentially dangerous for the young calves.
Why do we do whale surveys?
Intensive whaling activities in the 1800s drastically reduced the number of southern right whales. While, the whale population is slowly recovering, it is estimated that the number of whales currently represents a mere 10% of the pre-whaling population.
Surveys enable us to record changes in the whale population and breeding success, and determine the rate at which the southern right whale population is recovering.
How are surveys done?
Natural Resources Alinytjara Wilurara works together with partner agencies, volunteers and members of the local Aboriginal community to conduct annual monitoring at the Head of Bight. Monitoring is completed in the peak of the breeding season in mid to late August. The land-based population census is performed from the 90 metre-high Bunda cliffs, along a 10 kilometre transect that finishes in the bay at Twin Rocks. Long term monitoring has shown that the whales are primarily distributed within this study site.
What has been found?
Whales have unique identification markings that enable them to be tracked from year to year. More than 1000 individuals have been sighted over the years, allowing us to collect important data about whale population dynamics, breeding rates and life history.
Surveys have indicated that the number of whales aggregating at the Head of Bight is increasing by approximately 8% per year. Increased numbers of whales have also been observed further east in Fowlers Bay, which has led to investigations into the species’ distribution and habitat fidelity.
On average, 25-63 calves are born each year. Differing numbers of calves are expected, due to the three-year pattern of individual females returning to the Head of Bight for calving. It is important to continue monitoring whales nationally to determine if the population continues to increase or, alternatively, if the distribution of whales around the country is shifting.
Natural Resources Eyre Peninsula; Natural Resources Adelaide and Mt Lofty Ranges; Whale and Dolphin Conservation Society; Yalata Land Management