Fogg et al.: Age and growth of invasive Pterois volitans in the northern Gulf of Mexico 
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Figure t 
Map of the locations (black dots) and ecological regions (ecoregions) where red 
lionfish (Pterois volitans) were sampled from 2012 through 2015 in the north¬ 
ern Gulf of Mexico. Three ecoregions were sampled in this study: southeast 
(Florida Keys north to Anclote Keys, Florida), northeast (Anclote Keys north 
to Mobile Bay, Alabama), and central (west of Mobile Bay to Galveston Bay, 
Texas). The gray lines indicate depth contours from 10 to 200 m. 
(e.g., Sullivan Sealey and Bustamante, 1999; Yanez- 
Arancibia and Day, 2004; Spalding et al., 2007; Robertson 
and Cramer, 2014). Most ecoregions are identified on the 
basis of known biogeographic criteria, such as thermal 
regimes, habitat, floral and faunal assemblage composi¬ 
tion, sediment structure, currents and bathymetry, and 
coastal structural complexity. 
The northern tip of the Anclote Keys off the western 
coast of Florida, for example, has been identified as a 
point of a north-south ecoregion break (Beck and Odaya, 
2001; Beck, 2003; Spalding et al., 2007) in the northern 
GOM. This boundary between the southeast and north¬ 
east ecoregions is used mostly because of the thermal dif¬ 
ferences between the 2 ecoregions; in the winter months, 
water temperatures are consistently lower in the north¬ 
east ecoregion than in the southeast ecoregion (tempera¬ 
ture data were obtained from NOAA’s National Data Buoy 
Center, website). The Mississippi River often is used to 
divide the northern GOM into east and west ecoregions; 
however, we follow the ecoregion delineation based on 
Beck (2003) and Yanez-Arancibia and Day (2004), dividing 
our study area into central and northeast ecoregions. Our 
northeast ecoregion, which is considered the east ecoregion 
by Beck and Odaya (2001), Beck (2003), and Yanez-Aran¬ 
cibia and Day (2004), is characterized by less freshwater 
input, sandier sediments, and enhanced water clarity com¬ 
pared with the central ecoregion where increased fresh¬ 
water input, lower salinities, and muddy sediment input 
dominate. The northeast ecoregion is dominated by sea- 
grass meadows, but the central ecoregion is mainly salt 
marsh (Beck, 2003; Yanez-Arancibia and Day, 2004). 
Total length, measured in millimeters, and total weight, 
measured in grams, were recorded, and weight-length rela¬ 
tionships were calculated by sex and ecoregion. These data 
were used to estimate the weight-length power functions. 
The weight-length data were log transformed (base 10) 
prior to an analysis of covariance (ANCOVA), with TL as 
the covariate. An ANCOVA was first completed for each 
sex separately, comparing the weight-length relationships 
found across each of the 3 ecoregions. If no significant differ¬ 
ences were found across ecoregions, data were pooled and a 
second ANCOVA was completed to compare weight-length 
relationships for each ecoregion by sex. If the weight-length 
relationships for any ANCOVA violated the homogeneity 
of slopes assumption (parallelism), separate models were 
used. The estimated marginal means from these analyses 
were used to make comparisons between sexes of weight 
adjusted for mean TL. All ANCOVA were completed by 
using SPSS Statistics 2 , vers. 20 (IBM Corp., Armonk, NY). 
The sagittal otoliths were removed from red lionfish, and 
the left otolith was embedded and sectioned to a 300-pm 
thickness following Secor et al. (1991). Prepared otoliths 
2 Mention of trade names or commercial companies is for identi¬ 
fication purposes only and does not imply endorsement by the 
National Marine Fisheries Service, NOAA. 
