Fogg et al.: Age and growth of invasive Pterois volitans in the northern Gulf of Mexico 
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g> 
1 
1400 
1200 
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800 
600 
400 
200 
0 
1400 
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B 
Southeast ecoregion y = 1 x 1Q-®x 3 - 4434 ; R 2 = 0,9735 
Figure 2 
Weight-length relationships by ecological region (ecoregion) for (A) male and (B) female 
red lionfish (Pterois volitans ) collected from 2012 through 2015 in the northern Gulf of 
Mexico. Circles indicate data for fish collected in the southeast ecoregion (Florida Keys 
north to Anclote Keys, Florida), squares indicate data for fish from the northeast ecore¬ 
gion (Anclote Keys north to Mobile Bay, Alabama), and triangles indicate data for fish 
from the central ecoregion (west of Mobile Bay to Galveston Bay, Texas). i? 2 =coefficient 
of multiple determination. 
across all 3 ecoregions for red lionfish had significantly 
different slopes by sex (ANCOVA: F 1 4670 =21.96, P<0.001; 
Table 1A), indicating that females had a steeper weight- 
length relationship than males (Table 1A, Fig. 3) and, 
therefore, had a greater weight at a given TL. Pairwise 
comparisons of weight-length relationships by ecore¬ 
gion (Table IB) revealed a significant difference for male 
red lionfish only between the southeast and northeast 
ecoregions (ANCOVA: Fi ; 2038 = 8.16, P=0.004; Table IB); 
whereas, significant differences were observed for female 
red lionfish in all comparisons between ecoregions except 
between the southeast and central ecoregions (ANCOVA: 
Fi ,io25 = ^-61> P-0.436; Table IB). However, in all ecore¬ 
gions, males attained larger weights when adjusted for TL 
than females (Table 2). For a number of comparisons of 
ecoregions (Table IB), weight-length relationships were 
significantly different, but the differences in weight were 
minimal on the basis of their estimated marginal means 
adjusted for TL (females: 18.21 g; males: 22.75 g; Table 2), 
and male red lionfish achieved a greater mean weight 
(333.62 g [standard error (SE) 3.58]) compared to females 
(195.13 [SE 3.69]) (Table 2). 
From the 4250 pairs of otoliths that were extracted, 
a subsample of 1607 pairs of otoliths (744 males, 716 
females, and 147 fish of unknown or undetermined sex) 
were randomly selected and processed from red lionfish 
ranging in size from 81 to 434 mm TL. Age agreement was 
reached for 1412 pairs of otoliths (87.9%) from that subsa¬ 
mple. The APE for analysis of otoliths from the southeast 
ecoregion was 7.7, the APE for the northeast ecoregion was 
14.2, and the APE for the central ecoregion was 11.7. With 
analysis results from all 3 ecoregions pooled, the APE 
between readers was 12.1. Annual increment formation 
was confirmed by using marginal increment analysis, with 
marginal increment widths most complete in May and 
gradually decreasing until a minimum index of completion 
