Effects of temperature on physiological performance and behavioral thermoregulation in an invasive fish, the round goby

Abstract

Invasive species exert negative impacts on biodiversity and ecosystems on a global scale, which may be enhanced in the future by climate change. Knowledge of how invasive species respond physiologically and behaviorally to novel and changing environments can improve our understanding of which traits enable the ecological success of these species, and potentially facilitate mitigation efforts. We examined the effects of acclimation to temperatures ranging from 5 to 28°C on aerobic metabolic rates, upper temperature tolerance (critical thermal maximum, CTmax), as well as temperature preference (Tpref) and avoidance (Tavoid) of round goby (Neogobius melanostomus), one of the most impactful invasive species in the world. We show that round goby maintained a high aerobic scope from 15 to 28°C; that is, the capacity to increase its aerobic metabolic rate above that of its maintenance metabolism remained high across a broad thermal range. Although CTmax increased relatively little with acclimation temperature compared to other species, Tpref and Tavoid were not affected by acclimation temperature at all, meaning that round goby maintained a large thermal safety margin (CTmax−Tavoid) across acclimation temperatures, indicating a high level of thermal resilience in the species. The unperturbed physiological performance and high thermal resilience was likely facilitated by high levels of phenotypic buffering, which can make species readily adaptable and ecologically competitive in novel and changing environments. We suggest that these physiological and behavioral traits could be common for invasive species, which would only increase their success under continued climate change.

Ecological responses to elevated water temperatures across invasive populations of the round goby (Neogobius melanostomus) in the Great Lakes basin

“…Acclimation can allow an organism to shift its thermal tolerance upward, but there are still physiological constraints that cannot be overcome, and prolonged exposure to high temperature can impose metabolic costs (Pörtner and Farrell 2008;Schulte 2014). Metabolic rates in multiple populations of round goby increase with temperature, particularly past 26°C (Lee and Johnson 2005;Drouillard et al 2018;Christensen et al 2021); therefore, at these elevated temperatures there are higher energetic demands placed on gobies, requiring physiological adjustment. In studies of brook trout (Salvelinus fontinalis), CTmax has been found to plateau between 20°C and 25°C, and molecular stress responses increase past 20°C (Chadwick and McCormick 2017;Morrison et al 2020).…”

“…Overall, reduced feeding rates of round goby are likely due to performance trade-offs and behavioural changes associated with elevated temperatures. As described above, elevated metabolic rates have been measured at high temperatures (≥26°C) in round goby (Lee and Johnson 2005;Drouillard et al 2018;Christensen et al 2021). Acclimation to stressful temperatures introduces trade-offs between maintaining metabolic function and resource acquisition (Schulte 2015)-such that as an organism's metabolism is driven higher, more energy is required for simple performance maintenance (Morley et al 2019).…”

“…In addition to potential evolutionary adaptation, some populations established in the lower Great Lakes could have inherently greater thermal plasticity, or they experience selection pressures that favour more plastic phenotypes than in the St. Lawrence River (Hoffmann and Sgrò 2011;Seebacher et al 2015). In any case, round gobies in the lower Great Lakes appear to be significantly more thermally tolerant than their counterparts in the St. Lawrence River, as well as at least one population in Denmark (Christensen et al 2021). Successful invaders in general are expected to have broader tolerances and higher acclimation capacity, allowing them to overcome abiotic environmental barriers to establishment and subsequent population expansion (Kelley 2014).…”

“…whereas Christensen et al (2021) measured CT max for a round goby population in Denmark at temperatures between 10°C and 28°C.…”

Impacts of the invasive round goby (Neogobius melanostomus) on benthic invertebrate fauna: a case study from the Baltic Sea

“…natural boulder reefs or man-made structures like harbor walls and jetties; Young et al 2010;Kornis et al 2012). Round gobies possess several invasive characteristics such as high competitiveness for territory, a broad diet, dispersal ability, and broad temperature and salinity tolerances (Kornis et al 2012;Azour et al 2015;Behrens et al 2017;Christensen et al 2021). As such, the round goby is generally thought to have negative impacts on recipient ecosystems and indigenous taxa.…”