Phone: (+61 8) 6488 8118
Identifying Critical Cetacean Habitats for Humpback Whales (Megaptera novaeangliae) off the Northwest Coast of Australia
During southward migration, the West Australian population of humpback whales (breeding stock D) aggregate in sheltered areas along the coast, called resting areas. My research is quantifying the importance of these resting areas to the humpback whale population, and if they can be classed as critical cetacean habitat. The first part of this research is to understand the behavioural ecology of resting areas, including habitat preference and carrying capacity within these areas. The second part will use mathematical modeling to determine if there is an energetic advantage to resting. While humpback whales are migrating, they do not actively feed and rely on their blubber stores to meet the energetic demands of migration and breeding. Any changes in energy budget use over the migration cycle could impact the ability to reach the foraging grounds in the Southern Ocean before these energy stores run out. The model of whale energetics developed in this research aims to determine the impact to this energy budget if the whales could no longer use the resting areas, and so assess how essential resting areas are to whale and if these areas can be defined as critical habitats.
The WA population of humpback whales is growing quickly, with numbers reportedly increasing by at least 10% every year. At the same time, the WA coastline is becoming increasing developed for residential and industrial purposes. It is therefore important to manage the co-use of ocean space between humans and whales, as the demand for space from both sides continue to increase. This study will investigate the space requirement of whales while using resting areas, and the implications to future space use with an expanding population. Furthermore, the energetic modeling will provide a new approach in assessing the importance of a habitat to a population, providing a quantitative measure of impact under scenarios of disturbance.