SPAWNING FREQUENCY AND EGG-PRODUCTION OF CAPTIVE SPOTTED SEA-TROUT

Nine mature spotted seatrout Cynoscion nebulosus (seven females and tw o males) were placed in a recirculating-water culture system at the Un iversity of Miami Experimental Hatchery in July 1993. Photoperiod and water temperature were maintained at 14 h light:10 h dark and 27.5 deg rees C. Spotted seatrout held in this controlled photo-thermal culture system spawned on 172 occasions between August 1, 1993, and April 22, 1994, producing approximately 168 million eggs. On average, spawning occurred every 1.5 d. The 172 spawns during the 265-d spawning period represent an average of 24.6 spawns/female or 1 spawn/female every 10. 8 d. The mean volume of eggs collected per spawn was 306 mt (SD = 215) . The estimated average number of spotted seatrout eggs per milliliter was 3,184 (SD = 499). The mean percentage of viable eggs per spawn wa s 47.5% (SD = 29). Spotted seatrout held in the constant photo-thermal regime of 14 h light:10 h dark and 27.5 degrees C consistently produc ed eggs over a 9-month period.