Distribution, site affinity and regional movements of the manta ray, Manta alfredi (Krefft, 1868), along the east coast of Australia

Abstract

Despite the increasing tourism interest worldwide for the manta ray, Manta alfredi, very little is known about its biology and ecology. Knowledge of its distribution and movement patterns is important for conservation purposes. Here we describe the distribution, site visitation and movements of M. alfredi along the east coast of Australia. Photographic identification techniques were used to identify individual manta rays at three study sites: Lady Elliot Island, North Stradbroke Island and Byron Bay. Of 388 M. alfredi individuals identified at Lady Elliot Island, 187 (48%) were subsequently re-identified at least once at the same site. In total, 31 individuals were identified at both Lady Elliot Island and North Stradbroke Island (~380 km to the south) and 4 at both Lady Elliot Island and Byron Bay (~500 km to the south). Manta alfredi was present all year around at Lady Elliot Island, although in higher numbers in winter, and was mainly observed at North Stradbroke Island and Byron Bay from mid-spring to mid-autumn. This is the first report of seasonal movements and site affinity for M. alfredi in eastern Australian waters and emphasises the value of photographic identification for monitoring the occurrence of individuals.