Spawns in spring, the date depending on the locality. Temperature at time of spawning in New York was 10 C (Scott and Crossman 1973). Breeding season may last 2-3 months from time of nest selection to departure of young. Female spawns once per season. Male guards eggs (sometimes from multiple females); eggs hatch in 17 days at 11-13 C. Sexually mature in 2-3 years. (Becker 1983, Scott and Crossman 1973).