Investigating physiological mechanisms and ecological consequences of a climate-driven range extension of a marine predator (Chrysophrys auratus) into southeast Tasmania

Mr Barrett Wolfe1, Dr Quinn Fitzgibbon1, Dr Jayson Semmens1, Dr Sean Tracey1, Dr Gretta Pecl1,2

1Institute for Marine and Antarctic Studies, University Of Tasmania, Hobart, Australia, 2Centre for Marine Socioecology, University of Tasmania, Hobart, Australia

The southeast Australian ocean warming hotspot has been host to a number of ongoing marine species redistributions, and thus has the capacity to serve as a natural laboratory to investigate the mechanisms underpinning these phenomena and their resulting ecological consequences. Capitalising on the ongoing range extension of the teleost marine predator snapper (Chrysophrys auratus, Sparidae) into southeast Tasmania, this project explores physiological and ecological dimensions of range extensions with integrated lab and field research. Laboratory-based swim tunnel respirometry was used to compare metabolic and swimming performance of southeast Tasmanian-caught snapper at optimal and range-edge minimum temperatures to identify potential thermal limitations. These data were used to calibrate acceleration-logging acoustic tags that were subsequently deployed in wild snapper to quantify patterns of snapper behaviour and energetics at their current range edge, and how temperature influences these patterns. Combined with gut content analysis, these data will be used to estimate the diet and prey consumption of snapper in Tasmania as a proxy of ecological pressure now and under future forecasted warming. Other aspects of the project underway include comparison of somatic and reproductive growth from snapper across their range and identifying the potential origin of range-edge snapper with otolith microchemistry. These data will not only inform management in Tasmania of this important predator and fisheries target, but also provide insight into cold limitation and range extensions for similar marine species globally.


Originally from a small fishing community on the Chesapeake Bay, US, Barrett moved to Hawai’i in his teens to pursue a B.Sc. in marine biology at the University of Hawaii followed by an M.Sc. at California State University Long Beach Shark Lab where he was involved in a number of fish and shark tracking studies related to conservation and environmental remediation. Barrett came to Tasmania in 2016 for PhD research at IMAS combining his background in movement ecology and interest in ecophysiology to understanding predatory fish species redistributions. He is an exuberant freediver and vegetable gardener.

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