A/Prof Will Figueira1, Prof David Booth2, Mr Riccardo Cannas1, Ms Giglia Beretta2, Mr Luke Brown2
1University of Sydney, Sydney, Australia, 2Univeristy of Technology Sydney, Sydney, Australia
As oceans warm due to climate change, it is becoming increasingly common to find tropical fish species occurring in temperate habitats. These vagrant fishes have the potential to greatly impact local communities and represent the early phase of range shifts. Here we combine data from an 18 year monitoring program of tropical vagrant fishes in SE Australia with lab based analyses of thermal metabolic and swimming performance to evaluate the relative establishment potential for different vagrant species. Metrics of thermal tolerance established by evaluating the rate of decline in abundance with temperature for individual species were generally well related to propensity for individual species to occur as overwinters. We found thermal tolerance patterns tended to vary most strongly within families rather than amongst them. There was correspondence between the level of cold tolerance of a species with is metabolic performance though patterns were generally better explained by swim speed performance. This results suggests swim speed may be of more direct relevance than metabolic scope to the loss of individuals as temperature drops. These results highlight the utility of integrating abundance series, temperature data and lab-based analysis to gain a better understanding of the range expansion potential of tropical fishes.
Will Figueira is an A/Professor at the University of Sydney in Australia. His work focuses broadly on the population biology of marine fish and he has special interest in the mechanisms driving the range expansion of tropical fishes into temperate regions.