Site fidelity and sex-specific migration in a mobile apex predator: implications for conservation and ecosystem dynamics

By A. Barnett, K. Abrantes, J. Stevens, J. Semmens. 2011

106 citations recorded by the source corpus.

Combining movement behaviour with other ecological information of predators and their prey is essential for an adequate understanding of ecosystem dynamics. The movement patterns of broadnose sevengill sharks, Notorynchus cepedianus, were monitored with acoustic and satellite technology in coastal areas of southeast Tasmania, Australia. Individuals were tagged in two habitats (Norfolk Bay and the Derwent Estuary) for which we had ecological information such as diet, population structure and abundance. Notorynchus cepedianus showed seasonal site fidelity in the use of the coastal habitats. The general pattern was for sharks to exit coastal areas over winter and females to return the following spring and males in summer. Their movement into these coastal areas coincided with high seasonal abundance of their known prey species during summer, suggesting feeding site fidelity. Individuals tagged in two coastal areas showed low spatial and dietary overlap, suggesting localized site fidelity and fine spatial scale resource partitioning. This has rarely been reported for large mobile predators. Both satellite and acoustic methods showed that males make northerly migrations during winter to distances of at least 1000 km. The combined use of tracking, diet and abundance information demonstrated that N. cepedianus are likely to exert significant predation pressure on prey inhabiting these areas during summer. Overall, this study highlights the benefit of complementing movement data with other ecological information to understand the habitat use of large mobile predators and their potential influences on ecosystem structure and function.

Subfields: Global and Planetary Change, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/3e8e826d8f520a343fc6eedc08dee9a3f249b0b5

Citations in the corpus

• Use of marine protected areas and exclusive economic zones in the subtropical western North Atlantic Ocean by large highly mobile sharks (2016, unknown): “…for reef sharks, Escalle et al. (2015) found that 65% of these could benefit sharks, while 35% suggested no-take zones were too small to offer protection given the scale of shark movement (e.g. Chapman et al. 2005; Heupel et al. 2010; Barnett et al. , 2011; Bond et al. , 2012; Knip et al. , 2012).”