Determination of standard and field metabolic rates in two great lakes invading fish species: round goby (Neogobius melanostomus) and tubenose goby (proterorhinus semilunaris)

Although both round (Neogobius melanostomus) and tubenose (Proterorhinus semilunaris) gobies were introduced to the Great Lakes around 1990, their differential range expansion post-invasion remains poorly understood. Metabolic rates of round and tubenose gobies were evaluated to determine the influence of physiological tolerance on invasive species success. Standard metabolic rates (SMR) of round and tubenose gobies were measured across temperatures using intermittent flow respirometry. Tubenose gobies showed higher SMR, reaching metabolic optima at lower temperatures (23ºC) and exhibiting elevated stress responses at high temperatures. Field metabolic rates (FMR) of round gobies from three Great Lakes populations were also compared using chemical tracers. Although genetic differences between round goby populations have been documented, similar FMRs were seen among populations. These results suggest that SMR is a useful approach to compare differences in temperature dependent physiological tolerance of invasive species, and that FMR can be used to evaluate metabolic costs among wild populations.