SPAWNING RHYTHMS OF COMMON SNOOK IN FLORIDA

Common snook Centropomus undecimalis were sampled monthly from the Jup iter-Lake Worth area of Florida's Atlantic coast during 1989 and 1991 (1452 fish) and from Tampa Bay on Florida's Gulf of Mexico coast durin g 1958 and 1989 (2090 fish). Group-synchronous oocyte development was demonstrated. Ovarian maturation began during March or April on both c oasts. Spawning was first detected histologically in April during 1989 and 1991 on the Atlantic coast and during May in 1988 and in April in 1989 on the Gulf coast. In each year, spawning ended during October o n the Atlantic coast and during September on the Gulf coast. Ovarian h istological evidence suggested that individual females may spawn every 1.1-2.5 days between 1400 and about 2000 hours. Final oocyte maturati on occurred independently of either tidal cycle or lunar phase, and so me common snook were observed in prespawning or spawning condition on every day sampled. Spawning occurred in or near major inlets to the At lantic Ocean and the Gulf of Mexico, in secondary passes to larger inl and bays and bayous, and around nearshore islands. (C) 1998 The Fisher ies Society of the British Isles.