Factors Influencing the Thermal Response of North American Freshwater Fish

Habitat temperature is a major determinant of performance and activity in fish. We examined the relationship between six temperature metrics describing the growth (optimal growth temperature and final temperature preferendum), survival (upper incipient lethal temperature and critical thermal maximum), and reproduction (optimum spawning temperature and optimum egg development temperature) requirements of North American freshwater fish species. The results showed that all metrics were highly correlated, especially those within each life process.  As expected, values for different metrics fell into distinct groups that were associated with reported thermal preference classes. However these metric values were also associated with reproductive guilds, and spawning season. We will discuss how these linkages between thermal metrics and reproductive behaviour may interact through both  community diversity and environmental variation to determine the degrees of competition for spawning sites and larval food resources found in limnetic ecosystems.