NOTE Macchi: Estimate of spawning frequency and batch fecundity of Cynoscion striatus 
379 
Because vitellogenic oocytes are recruited continu- 
ally during the reproductive season, it is necessary 
to determine the batch fecundity and the number of 
spawnings in the season in order to estimate total 
egg production (Hunter et al., 1985). Spawning fre- 
quency estimated from the percentage of hydrated 
ovaries (12%) was similar to those calculated with 
postovulatory follicles (11-13%). The average be- 
tween day-0 and day-1 POF’s ( 12 ±6%) indicates that 
spawning occurred once every 8 days during the main 
peak of the reproductive season (November). Daily 
spawning fraction of C. striatus was similar to that 
reported for three other scienids: Seriphus politus 
(De Martini and Fountain, 1981), Genyonemus linea- 
tus (Love et al., 1984) and Cynoscion nebulosus (Brown- 
Peterson et al., 1988), but was lower than estimates 
for Pogonias cromis (31%) (Fitzhugh et al., 1993). 
Annual spawning frequency estimated for Sciaenops 
ocellatus (Wilson and Nieland, 1994) and Cynoscion 
regalis (Lowere-Barbieri et al., 1996) varied widely, 
3 to 80 days and 2 to 13 days, respectively. Daily 
spawning percentage of white croaker ( Micropogo - 
nias furnieri) in the Southwest Atlantic was 8.83% 
(Macchi et al., in press), indicating that the average 
interval between spawnings for this sciaenid is about 
12 days . 
Cassia (1986) estimated total fecundity for C. 
striatus by counting the number of growing oocytes, 
which is inappropriate for a multiple spawning spe- 
cies (Hunter and Goldberg, 1980). This author esti- 
mated a total fecundity of 600,000 oocytes for one 
40-cm-TL female, when the batch fecundity for that 
length is about 100,000 hydrated oocytes. In the 
present study, analysis of variance applied to the fe- 
cundity data from “El Rincon” and the Uruguayan 
coast indicated no statistical differences between 
these areas. Batch fecundity was a power function 
of length and a linear function of ovary-free body 
weight and ranged between 50,000 (34 cm TL) and 
450,000 (53 cm TL) hydrated oocytes. Batch fecun- 
dity values estimated for striped weakfish were 
higher than those obtained for smaller sciaenids, 
such as Genyonemus lineatus (800-37,200 oocytes) 
(Love et al., 1984) and Seriphus politus (5,000-90,000 
oocytes) (De Martini and Fountain, 1981). Sciaenids 
with length ranges similar to C. striatus, such as 
Cynoscion regalis (Lowere-Barbieri et al., 1996) and 
Cynoscion nebulosus (Brown-Peterson et al., 1988), 
show slightly higher batch fecundity values. The re- 
lations between batch fecundity vs. length and batch 
fecundity vs. weight for these species had relatively 
low coefficients of determination, similar to those for 
striped weakfish. The mean relative fecundity for C. 
striatus (210 ±35 oocytes/g ovary-free body weight) 
was less than that obtained for Cynoscion nebulosus 
(451 ±43 oocytes) (Brown-Peterson et al., 1988) and 
