Benjamin Gray

PhD project summary: Assessment of the interactive effects of climate change, floods, and discard stress on the commercially important Mud Crab (Scylla serrata) and Blue Swimmer Crab (Portunus armatus)

Giant mud crabs and blue swimmer crabs are the most economically important crab species in Australia, supporting a harvest >3000 tonnes per annum. In eastern Australia, altered land use practices adjacent to coastal waterways and recent rainfall runoff events associated with the 2020-2023 La Niña are perceived to have impacted commercial catch and quality. Flood events reduce water quality in estuaries and can carry contaminants such as pesticides from adjacent land use activities. However, the potential for extreme environmental conditions and contaminants to cause mortality and sub-lethal physiological stress of many exploited estuarine species, remains unknown. Further, fishing gears which target (or incidentally catch) these species are poorly selective, resulting in discarding of large numbers of individuals that are physically damaged. My thesis will investigate the interactive effects of reduced salinity from heavy rainfall events and the associated inputs from agricultural run-off, and simulated discarding stress to determine the impacts on crab physiology.