Behavior of winter flounder, Pseudopleuronectes americanus, during the reproductive season: laboratory and field observations on spawning, feeding, and locomotion

Continuous observations in a large research aquarium (121 kL) over a 14-wee k period were combined with field collection in the Navesink River estuary, New Jersey, to explore the behavior of winter flounder (Pseudo-pleuronecte s americanus) during and after the spawning season. Ten males and ten femal es held in the aquarium spawned over a 60-day period, with an average of 40 spawns per female and 147 spawns per male. Males initiated all observed sp awning events, which occurred throughout the night, but primarily between s unset and midnight. Spawning by one pair frequently elicited sudden converg ence and spawning by secondary males (up to six individuals); consequently, strictly paired spawning was uncommon (22% of events). Males and females w ere almost entirely nocturnal during the reproductive season but became inc reasingly diurnal during the postspawning season.