Oocyte Maturation and Spawning in Wild American Lobsters (Homarus americanus): Lack of Evidence for Significant Regulation by Photoperiod

Abstract

The literature indicates that spawning in the American lobster (Homarus americanus) requires exposure to short days followed by long days, but our previous experiments with mature female lobsters showed no such requirement. To reevaluate the reported photoperiod requirement and to determine whether a photoperiod stimulus for ovarian maturation might occur well before the current spawning season, we held wild-caught mature Gulf of St. Lawrence females on either long (LD 16:8) or short (LD 1:23) days starting at the autumnal equinox. Females held on both short and long days spawned at the normal time the following July, indicating no effect of photoperiod even 10 mo before normal spawning time. This study extends previous work by showing that Gulf of St. Lawrence lobsters held on typical East Coast seawater temperatures will spawn at the normal time without being exposed to either short-day or long-day photoperiod between 22 September and the following July.