Post-spawning defence by male brook charr is linked to perceived paternity

Abstract Salmonine fishes are generally thought not to exhibit male parental care, although brief post-spawning mate-guarding by males is known for a number of species, often populations where eggs subjected intense predation (egg cannibalism). Here, detailed in situ data on the spawning behaviour brook charr, Salvelinus fontinalis , from naturally reproducing lake population used test whether mate guarding (i.e. paternal care) related perceived paternity. From video records events ( n = 20), we documented novel whereby dominant curtails ahead female (by ~ 3 s) and immediately inspects nest. Afterwards, significantly reduces courtship (quivers) but aggressively defends with same intensity as prior spawning. The duration (range: 3–48 min), however, declined increasing numbers peripheral that had rushed into nest at Neither active females present grounds nor body size influenced amount time spent guarding. Extensive revisitation (80% visits) sites during focal sampling bouts highlights importance male’s ability predict readiness spawn significant component reproductive success. Thus, appear guard cost acquiring other mating opportunities adjust depending upon their