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Fishery Bulletin 112(2-3) 
1.5 -r 
-1.5 -1 0 -0 5 0 0 0 5 1 0 1.5 
Principal component one 
Figure 7 
Biplot of first (43.3%) and second (25.0%) principal components from principal component analysis 
(PCA) on the basis of the relative measures — each denoted with an arrow — of reproductive traits 
(spawning-season duration [SPAWN_DUR], relative batch fecundity [REL_FEC], and age at maturity 
[AGE_MAT]) and somatic traits (maximum total length [MAX_TL] and the weight-at-length parame- 
ter [6]) for 17 populations of sciaenids in 3 regions: Gulf of Mexico (GOM), Pacific Ocean, and Atlantic 
Ocean. Numbered points indicate sciaenid populations: (1) GOM Silver Perch ( Bairdiella chrysoura ), 
(2) GOM Sand Seatrout (Cynoscion arenarius), (3) Atlantic Spotted Seatrout (C. nebulosus), (4) GOM 
Spotted Seatrout, (5) GOM Silver Seatrout (C. nothus), (6) Atlantic Weakfish (C. regalis), (7) Pacific 
White Croaker ( Genyonemus lineatus), (8) GOM Spot ( Leiostomus xanthurus), (9) Atlantic Southern 
Kingfish (. Menticirrhus americanus), 10. GOM Southern Kingfish, (11) Atlantic Atlantic Croaker (Mi- 
cropogonias undulatus), (12) GOM Atlantic Croaker, (13) GOM Black Drum ( Pogonias cromis ), (14) 
Pacific Spotfin Croaker (. Roncador stearnsii), (15) GOM Red Drum ( Sciaenops ocellatus), (16) Pacific 
Queenfish (, Seriphus politus), and (17) Pacific Yellowfin Croaker (Umbrina roncador). The letters A-E 
indicate the 5 groups of sciaenids identified through PCA. The large circle represents a maximum cor- 
relation of 1 between original variables in the PCA analysis and the factor loadings for each variable 
that were generated by the PCA. 
Spawning frequency for batch-spawning species like 
Southern Kingfish, when combined with batch fecun- 
dity, provides an estimate of the total annual repro- 
ductive output of a species. Histological confirmation 
of multiple spawnings per season for populations of 
Southern Kingfish in Brazil and the SAB have been 
reported recently on the basis of the appearance of 
POFs and surrounding oocytes in multiple stages of 
development (Haluch et al., 2011; McDowell and Rob- 
illard, 2013). In our study, the seasonal spawning fre- 
quency was found to be about 7 days between spawn- 
ings with a peak of 3-6 days (depending on method, 
POF or OM) during June and July in the northcen- 
tral GOM. This interspawning interval is one of the 
longest ones reported among the Sciaenidae (see Ap- 
pendix) and contrasts with that of 2-4 days between 
spawnings for the SAB population of Southern King- 
fish (McDowell and Robillard, 2013). However, spawn- 
ing-frequency data are based on a 4-month spawn- 
ing season in Georgia and a 6-month season in the 
GOM — a difference that may account for some of this 
variation. 
