Insights on Mitochondrial Genetic Variation in Chesapeake Bay Summer‐Resident Cownose Rays

Abstract

AbstractThe Cownose Ray Rhinoptera bonasus has been hunted and fished without restrictions in the Chesapeake Bay in recent years despite minimal understanding of its population size or stability. We used genetics to characterize Cownose Rays from three locations in the Chesapeake Bay in an effort to better understand their population structure. The Chesapeake Bay individuals were compared with Cownose Ray samples from a location in their southern U.S. range, the Gulf of Mexico. Direct sequencing of 1,094 base pairs of two mitochondrial gene regions revealed 16 haplotypes with frequencies that were not significantly differentiated by collection site within the bay. Frequencies of haplotypes from the Gulf of Mexico (at Tampa, Florida) were significantly different from those at each of the Chesapeake Bay sites, supporting previous work that determined separate migratory patterns for Atlantic and Gulf of Mexico individuals. The possibility of sex‐specific patterns in genetic variation by sampling site remains to be determined. A more robust understanding of how genetic variation is distributed among locations and by sex in Cownose Rays will be essential in the event that management of the species becomes necessary.Received July 6, 2016; accepted January 18, 2017 Published online March 23, 2017