Baremore and Rosati: A validated, minimally deleterious method for aging sturgeon 
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Figure 3 
Ventral surface of Gulf sturgeon ( Acipenser oxyrinchus desotoi ) pectoral fins (A) just after removal of a segment of the sec- 
ond marginal pectoral-fin ray, (B) 6 months after removal of that segment, and (C) immediately after removal of the right 
fin spine and left second marginal fin ray. An arrow in each panel indicates the place where the second marginal fin ray 
was removed, and the star in the final panel marks the site of the fin spine removal. Second marginal pectoral-fin rays were 
removed from live Gulf sturgeon in the Choctawhatchee and Apalachicola rivers during 2010, and these photos indicate that 
removal of this fin ray is less invasive than removal of fin spines. 
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Fin spine band count 
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Figure 4 
Final band counts of pectoral fin spines and second marginal pectoral-fin rays 
from Gulf sturgeon ( Acipenser oxyrinchus desotoi ) (n= 222) captured in the Choc- 
tawhatchee River in 2010, from an archive of specimens that were collected in 
the Apalachicola and Choctwahatchee rivers in 2010, and from an archive of Gulf 
sturgeon captured on the Suwannee River in 1980-90. The graph indicates little 
systematic difference up to 25 band pairs between band counts from the second 
marginal fin ray and band counts from the fin spine. 
Validation of aging structure 
Annual band formation was validated for 3 Gulf stur- 
geon that were recaptured one year after being marked 
with OTC and for 1 Gulf sturgeon that was recaptured 
after 6 months. Visual assessment of the sections 
showed that, for sturgeon with 6, 7, and 8 total band 
pairs, 1 band pair was fully formed after the chemical 
mark from the OTC injection (Fig. 5). A Gulf sturgeon 
recaptured in October after being injected in Febru- 
