Variable Spawning Activity and Annual Fecundity of Weakfish in Chesapeake Bay

Abstract

Abstract In all, 1,403 weakfish Cynoscion regalis were collected in 1991 and 1992 from commercial fisheries in the Chesapeake Bay region. Female gonads were examined macroscopically and histologically. Weakfish showed a strong diel periodicity in spawning activity, with almost all fish spawning at dusk. Although fish spawned from May through August, spawning activity varied within season and between years. Spawning activity decreased in late June and early July in both 1991 and 1992, but increased again in late July only in 1991. Spawning activity within and between years showed a temporal pattern similar to that of body condition, as measured by Fulton's condition factor. Batch fecundities ranged from 75,289 to 517,845 eggs/female and significantly increased with both total length and somatic weight. Spawning frequency was higher in 1991 (once every 2–3 d) than in 1992 (once every 12–13 d), leading to an average annual fecundity of 7.4 million eggs/female in 1991 and 1.8 million eggs/female in 1992.