404 
Fishery Bulletin 113(4) 
Table 4 
The 3 extracted principal components of climate-related meteorological and hydrological variables 
that are considered to have influenced the variability of commercial landings (numbers and propor- 
tions per vessel ton week) of Gulf menhaden (Brevoortia patronus) from 1964 through 2010 in the 
northern Gulf of Mexico. Data were divided into 2 climate regions: central (Louisiana, Mississippi, 
Alabama, and Florida panhandle) and western (Texas). 
Extracted principal components 
Regions 
Variables 
1 st 
2 nd 
3 rd 
Central region 
Precipitation 
0.776 
-0.459 
Palmer Drought Severity Index 
0.740 
-0.463 
River flow 
0.719 
-0.563 
Air temperature 
0.342 
0.855 
Sea level 
0.727 
0.533 
Western region 
Palmer Drought Severity Index 
0.714 
-0.381 
0.500 
Air temperature 
0.940 
Sea level 
0.651 
0.578 
Precipitation 
0.689 
0.575 
Cube-root-transformed river flow 
0.673 
0.559 
Eigenvalue 
4.173 
2.648 
1.660 
Variance explained (%) 
41.734 
26.482 
16.596 
Cumulative variance explained (%) 
41.734 
68.216 
84.812 
driven by the strong, coastal upwelling and high river 
flow associated with meteorological (e.g., frequency of 
cold fronts and, therefore, low air temperatures as- 
sociated with northerly winds; Henderson and Vega, 
1996) and hydrological (e.g., precipitation; Douglas and 
Englehart, 1981) conditions related to the warm phase 
of ENSO. These conditions have the potential to en- 
hance larval development and survival of Gulf men- 
haden (Riley, 1937; Dagg and Whitledge, 1991; Grimes 
and Finucane, 1991; Hitchcock et al., 1997). In the in- 
tertidal zone, extreme winter low tides and cold tem- 
peratures associated with meteorological (e.g., northerly 
cold winds and cold fronts; Henderson and Vega, 1996) 
conditions related to the ENSO warm phase produce an 
accumulation of detritus through the die off of marsh 
grasses (Kirby, 1972; Day et ah, 1973). In spring, plant 
detritus collected during the winter is washed to open 
waters by flooding events produced by the prevailing 
southeasterly winds. During this season, juveniles move 
from the intertidal zone to open waters, where the avail- 
ability of detritus as a food source becomes crucial for 
their development and survival (Darnell, 1958). 
Acknowledgments 
The authors thank V. Guillory, K. Ibos, J. Adriance, P. 
Cook, and M. Harbison from the Louisiana Department 
of Wildlife and Fisheries, F. Martinez-Andrade from 
the Texas Parks and Wildlife Department, L. Hartman 
from the Marine Resources Division of the Alabama 
Department of Conservation and Natural Resources, 
and J. Anderson from the Center for Fisheries Research 
and Development at the Gulf Coast Research Labora- 
tory, University of Southern Mississippi for provid- 
ing us with the fishery-independent data used in this 
study. Commercial landings data were furnished by D. 
Vaughan and J. Smith of the National Marine Fisher- 
ies Service, NOAA. Data used in this publication was 
assimilated under NOAA 2010 Saltonstall-Kennedy 
Grant NA10NMF4270195: climate-related hydrological 
regimes and their influence in Gulf menhaden recruit- 
ment in the northcentral GOM. 
Literature cited 
Ahrenholz, D. W. 
1981. Recruitment and exploitation of Gulf menhaden, 
Brevoortia patronus. Fish. Bull. 79:325-335. 
Akaike, H. 
1981. Likelihood of a model and information criteria. J. 
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Anderson, J. D. 
2007. Systematics of the North American menhadens: 
molecular evolutionary reconstructions in the genus 
Brevoortia (Clupeiformes: Clupeidae). Fish. Bull. 
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Anderson, J. D., and W. J. Karel. 
2014. Limited genetic structure of Gulf Menhaden 
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