Comparison of First and Second Pectoral Fin Rays for Use in Aging Shortnose Sturgeon (Acipenser brevirostrum LeSueur, 1818)

Abstract

Acipenser brevirostrum (Shortnose Sturgeon) is an endangered fish found in eastern North American rivers. Age data are largely lacking for the species, particularly in southern rivers. Such data can be acquired by examining the annuli of the pectoral fin rays. This study's objective was to compare ages derived from the first versus second pectoral fin rays. In 2020, we obtained paired pectoral ray samples from 59 Shortnose Sturgeon from 2 Georgia rivers. After processing, 35 ray pairs were examined by 3 independent readers. Only 21% of ray pairs were assigned the exact same age; 56% of pairs were assigned ages within 1 year. There was considerable overlap in length at assigned age for both first and second pectoral rays.