292 
Fishery Bulletin 115(3) 
Table 2 
Estimates of spawning frequency of spawning capable Gulf menha- 
den ( Brevoortia patronus) collected from Mississippi and Louisiana 
coastal waters during 2014 through 2016. Estimates were derived 
by using 2 different calculation methods: postovulatory follicle 
(POF) and oocyte maturation (OM), including hydrated oocytes. 
Month 
n 
POF method 
OM method 
Early October 
32 
22%, 4.5 days 
6.25%, 16 days 
Late October 
63 
6.3%, 15.9 days 
41.3%, 2.4 days 
All October 
95 
4.6%, 8.6 days 
29.5%, 3.4 days 
Early November 
14 
21%, 4.76 days 
0.0% 
Late January 
16 
43.8%, 2.3 days 
37.5%, 2.6 days 
Late February 
6 
83%, 1.2 days 
0.0% 
Late March 
3 
0 
66.6%, 1.5 days 
All combined 
134 
23.1%, 4.3 days 
47.8%, 2.1 days 
females in the regressing reproductive phase 
ranged from 2.3 to 13.9%; atresia percent- 
ages >10% are suggestive of indeterminate 
fecundity. Similarly, calculations of total an- 
nual fecundity present conflicting evidence of 
determinate or indeterminate fecundity. To- 
tal fecundity of a 181-g female was 473,370 
eggs, based on total oocytes at the beginning 
of the season but 1,658,316 eggs based on 
BF and spawning frequency (suggestive of 
indeterminate fecundity), whereas total fe- 
cundity of a 132-g female was 204,347 eggs 
based on total oocytes at the beginning of 
the season and 174,958 eggs based on BF 
and spawning frequency (suggestive of de- 
terminate fecundity). Finally, although a 
steady decrease in GSI values as the season 
progresses (Fig. 3) is typical of species with 
determinate fecundity, this decrease can also 
occur in species with indeterminate fecundi- 
I 
Imm EDev Dev SC AS Rgs Rgn 
Age 1 and 2 in September: P= 0. 
Age 1 and 2 in September: P=0.047 
100 n £ 
n-19 
I 
1mm EDev Dev SC AS Rgs Rgn 
Age 2 and 3 in October: P=0.875 
Figure 4 
Distribution of female reproductive phases for Gulf menhaden ( Brevoortia patronus ) collected from the northern Gulf of 
Mexico during 2014 through 2016, by age at the beginning of the reproductive season: (A) age-1 and (B) age-2 females in 
September and (C) age-1, (D) age-2, and (E) age-3 females in October. The probabilities (P) from the results of a Kruskall- 
Wallace 2-sample test of similarity of distributions within a month are provided. The reproductive phases are immature 
(Imm), early developing (EDev), developing (Dev), spawning capable (SC), actively spawning (AS), regressing (Rgs), and 
regenerating (Rgn). 
