Observations on Hatching and Larval Release in the Lobster Homarus americanus

In the American lobster (Homarus americanus) larval release occurs most frequently at night, usually shortly after darkness, but batches of larvae are often released at different times throughout the day as well. The rapid beating of the pleopods by the female, which is necessary for larval release, usually lasts less than 1 min and is sometimes performed without any larvae emerging. The outer egg membranes of those eggs from which larvae will be released at any one time become broken open (hatch) throughout the period following the previous larval release, which means that some prelarvae are ready for liberation for periods up to 24 h prior to being released.