Roumillat and Brouwer: Reproductive dynamics of Cynoscion nebulosus 



479 



post-spawning females increased from 99r in August to 

 91% in September. Thus, the spawning season for spot- 

 ted seatrout in South Carolina extends from late April 

 through early September. 



Spawning frequency 



Day-0 POFs were found through 1800 h of the day fol- 

 lowing a spawning event. Day-1 POFs were first observed 

 in our routine samples when they were 36-37 hours old 

 (the second day following a spawning event) only when 

 water temperatures were below 25°C. Day-1 POFs were 

 excluded from our analysis of SF because they did not 

 provide evidence of a previous night's spawning event. 



Figure 3 illustrates the time line for POF atrophy in 

 spotted seatrout from 1-42 h after the onset of spawn- 

 ing at 1800 h. Because evidence of spawning for the first 

 12 h was documented only during a period when water 

 temperatures were greater than 25°C, all of the exam- 

 ples shown are indicative of atrophy in warmer tempera- 

 tures (Fig. 4). As indicated in Table 2, there was a time- 

 dependent deterioration of POFs such that only those 

 <24 h were detectable at water temperatures >25°C. 



Small sample sizes prevented calculation of monthly 

 SF for each age class by year. Therefore, we pooled 

 data for all three years of this study to obtain a single 

 monthly SF estimate by age class (Tables 3 and 4). 

 The interaction between month and age on SF could 

 not be statistically tested; however, age-3 fish spawned 

 more frequently than younger fish (Kruskal-Wallis, 

 P<0.05) and all seatrout spawned more frequently in 

 June (Kruskal-Wallis, P<0.05). Peaks in SF observed 

 for fish ages 2 and 3 in July and August, respectively 

 (Tables 3 and 4), were not statistically significant. 



Monthly SF values based on the occurrence of ova- 

 ries containing oocytes in FOM are also presented in 



Table 3. However, statistical comparisons were not fea- 

 sible because of the nonrandom collection of specimens. 

 Overall SF was estimated to be once every 4.4 days and 

 once every 5.1 days with the POF and FOM methods, 

 respectively. 



