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

Abstract

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 nondedicated 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°C, highest probability 21.8°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. KEY WORDS: Humpback whale · Megaptera novaeangliae · Spatial habitat modelling · Great Barrier Reef Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 447: [259][260][261][262][263][264][265][266][267][268][269][270][271][272] 2012 toring of marine species in marine ecosystems can be expensive and logistically prohibitive (Redfern et al. 2006). Increased human use of the marine environment has meant that human activities are posing a greater threat to the persistence of marine mammal populations (Evans 2008). Identifying critical habitat is therefore particularly important in areas where human activities are likely to have the greatest impact so that any deleterious human impacts can be mitigated. Predictive modelling of species' distributions and their habitat is one ap proach that is becoming increasingly popular and proving to be a costeffective approach when applied to marine mammal populations that are difficult to monitor (Redfern et al. 2006).Compared with critical habitat for terrestrial species, the identification and designation of critical habitat in the marine environment can be more complex and the boundaries may be less fixed (Evans 2008). The difficulty in identifying critical habitat largely depends on whether the habitat requirements are dependent on stable, geographical environmental parameters such as depth or top...

Movements and habitat use of reef manta rays off eastern Australia: offshore excursions, deep diving and eddy affinity revealed by satellite telemetry

“…To date, it is unknown where they go and what they do when not around LEI. In addition, it is unclear how M. alfredi disperse along the eastern Australian seaboard when undertaking long-distance movements (> 300 km) and whether they commonly utilise specific migratory corridors, as observed in other species off eastern Australia (Bansemer & Bennett 2011, Smith et al 2012 and in other regions (Zerbini et al 2006, Campana et al 2011.…”

Influence of environmental parameters on movements and habitat utilization of humpback whales (Megaptera novaeangliae) in the Madagascar breeding ground

“…However, they are also found in deep waters [26,27] and in shallow waters extended offshore during winter [28,29], where movement patterns and habitat use are poorly known. To date, only one study has investigated the movements of individual humpback whales in a breeding ground and established direct links with environmental parameters [30]. …”

An investigation of the roles of geomagnetic and acoustic cues in whale navigation and orientation

“…Antarctica to breeding grounds inside the Great Barrier Reef off Queensland, Australia (Noad et al 2006, Smith et al 2012). This population has been the focus of a postwhaling population survey since 1978 at Point Lookout on North Stradbroke Island, which is about 50 km east of Brisbane (Figure 3.1).…”