Identification of humpback whale breeding and calving habitat in the Great Barrier Reef

• Published in: Marine Ecology Progress Series
• Main Authors: Smith, Joshua N., Grantham, Hedley S., Gales, Nick, Double, Michael C., Noad, Michael J., Paton, David
• Format: Article in Journal/Newspaper
• Language: English
• Published: Inter-Research 2012
• Subjects: Humpback whale; Megaptera novaeangliae; Spatial habitat modelling; Great Barrier Reef; 1104 Aquatic Science; 1105 Ecology; Evolution; Behavior and Systematics; 2303 Ecology; Antarctic; Antarc*; Humpback Whale
• Online Access: https://espace.library.uq.edu.au/view/UQ:271484

During the winter months, from June to September, humpback whales Megaptera novaeangliae breed and calve in the waters of the Great Barrier Reef (GBR) after migrating north from Antarctic waters. Clearly defined wintering areas for breeding and calving comparable to those identified in other parts of the world have not yet been identified for humpback whales in the GBR Marine Park (GBRMP), mainly because of its large size, which prohibits broad-scale surveys. To identify important wintering areas in the GBRMP, we developed a predictive spatial habitat model using the Maxent modelling method and presence-only sighting data from non-dedicated aerial surveys. The model was further validated using a small independent satellite tag data set of 12 whales migrating north into the GBR. The model identified restricted ranges in water depth (30 to 58 m, highest probability 49 m) and sea surface temperature (21 to 23 degrees C, highest probability 21.8 degrees C) and identified 2 core areas of higher probability of whale occurrence in the GBRMP, which correspond well with the movements of satellite tagged whales. We propose that one of the identified core areas is a potentially important wintering area for humpback whales and the other a migration route. With an estimated increase in port and coastal development and shipping activity in the GBRMP and a rapidly increasing population of whales recovering from whaling off the east Australian coast, the rate of human interactions with whales is likely to increase. Identifying important areas for breeding and calving is essential for the future management of human interactions with breeding humpback whales.