Project number: 2018-034
Project Status:
Budget expenditure: $714,675.00
Principal Investigator: Morgan S. Pratchett
Organisation: James Cook University (JCU)
Project start/end date: 3 Mar 2019 - 3 Mar 2022


Coral trout (mainly, the common coral trout, Plectropomus leopardus) are critical in sustaining the Queensland CRFFF, and are also important target species for recreational, charter and indigenous fishery sectors. Recent research has indicated that the distribution, behaviour and population viability of coral trout are likely to change in response to recent and ongoing climate change. More specifically, populations of coral trout in the northern GBR are already exposed to maximum summertime temperatures that exceed their apparent thermal optima (27-30°C; Johansen et al., 2014; 2015), which was determined in laboratory studies. Unprecedented thermal anomalies have also caused extensive coral bleaching and associated coral mortality and habitat degradation in recent years, especially in the northern GBR (Hughes et al. 2017). Widespread and profound changes in the structure of reef habitats are likely to impact on recruitment success, prey availability and the availability of shelter for adult coral trout.

This project is critical for understanding the flow-on effects of changing reef habitats and environmental conditions on wild stocks of coral trout on the GBR. Importantly, this project builds on previous experimental studies to establish how fishes respond to changing conditions, explicitly considering the capacity for fishes to actually move or moderate their activity to minimise adverse effects of high and increasing water temperatures. Although, large and mobile reef fishes (such as coral trout) may be capable of moderating exposure to extreme temperatures, this will nonetheless affect where fishes occur and whether they can be caught. The project will address the FRDC priority research need “Influence of Changes in Reef Habitat Condition and Climate Change on Coral Trout — To Inform Abiotic Drivers of Coral Trout Stocks” and Queensland’s Sustainable Fisheries Strategy high priority research need for Coral Trout (east coast) assessment requirements — To determine the most appropriate indicators and harvest control rules for management procedures of the coral trout fishery.


1. Establish the capacity for thermoregulatory behaviour among common coral trout (Plectropomus leopardus), as well as measuring their preferred temperature
2. Test for changes in the distribution and behaviour of coral trout associated with seasonal and latitudinal variation in ocean temperatures
3. Explore effects of severe coral loss and habitat degradation (caused by recent mass-bleaching) on the abundance, diet and physiological condition of large-bodied fishery species, especially common coral trout
4. Test for long-term changes in abundance and catches of coral trout associated with reef-wide changes in habitat condition on the GBR
5. Provide management advice that accounts for changes in habitat and environmental conditions

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