Size-Specific Patterns in the Reproductive Cycle of the Killifish, Fundulus heteroclitus (Pisces: Fundulidae) from Sapelo Island, Georgia

2-2.5 months duration. The episodes were separated by a period of ca. 1.5 months during which there was little reproductive activity and an increase in somatic tissue weight. Spawning was not continuous during the reproductive episodes but occurred with a semilunar periodicity due primarily to the activity of large (-56 mm SL) adult fish. Small adults (36-45 mm SL) participated in fewer spawning events and tended to spawn with a lunar periodicity, especially in the first reproductive episode. Although fish of medium size (46-55 mm SL) usually spawned on a semilunar cycle, a majority of the individuals in this group occasionally skipped a spawning event and thus sometimes exhibited a lunar spawning rhythm. Spawning began later and ended earlier for small adults than for the larger size classes. During the first reproductive episode (late-Feb. through mid-May) most of the spawning in all size classes occurred on or just prior to peak spring tides associated with the full moon but in the second episode (July through mid-Sept.) occurred on or after the new moon tidal maxima. Individual size-specific fecundity was higher in the first reproductive episode than in the second, particularly during spawning events associated with full moon spring tides.