Poster Presentation Australian Society for Fish Biology Conference 2022

A chain reaction - dietary shifts of an apex predator, the tiger shark (Galeocerdo cuvier), along the eastern coast of Australia (#212)

Alexandra Ikpe 1 , Paul Butcher 2 , Johan Gustafson 3 , Christofer Clemente 1 , Alexis Levengood 1 , Bonnie Holmes 1
  1. University of the Sunshine Coast, Maroochydore, QLD, Australia
  2. Department of Primary Industries, New South Wales Government, Parramatta
  3. Coastal and Marine Research Centre, Griffith University, Gold Coast

Apex predator movements, fine-scale habitat use, and the drivers influencing these factors in a changing marine environment are not well understood.  Along the eastern coast of Australia, a climate change hotspot, the diet composition of the tiger shark is a major influential factor that follows both ontogenetic and bioregional shifts. The literature has shown variation in diet between Queensland and New South Wales, and between young and mature individuals. As ocean temperatures warm facilitating year-round residence of tiger sharks in NSW waters, changes to historic trophic webs from direct and indirect influence by the species will occur. The impact of this shift, for both tiger sharks and prey species, remains unknown. Using HD video cameras fitted on state-of-the-art CATScam tags and analysed in conjunction with stomach content and cloacal swabs (genetic metabarcoding), the generalised feeding mode of this species will be stratified by prey type, shark size, and location captured along the Australian east coast. These data will facilitate predictions on how their movements are influenced by, and have influence on, prey movement and ecosystems along the Australian east coast. As waters continue to warm, accurate predictions of shifts in shark home ranges, and their chain reactions, are critical for fisheries, shark control, and broader ocean systems management across southeastern Australia.