Rangewide Population Structure of the Clearnose Skate

Skates (family Rajidae) are benthic elasmobranchs that highly vulnerable to incidental fishery bycatch, discarded at sea, and poorly accounted for in catch records. Many aspects of skate life history, such as population structure, not well understood. Without this knowledge, indiscriminate removal may have deleterious effects on scientific, conservation, management efforts. The Clearnose Skate Rostroraja eglanteria is seasonally migratory widely distributed the coastal waters eastern United States northeastern Gulf Mexico. This study used molecular techniques assess structure use a biological reference point further research management. Specimens were collected from 2014 2019 by fisheries-independent surveys. High-throughput genotyping-by-sequencing was identify single nucleotide polymorphisms, resulting two data sets: one consisting 8,914 loci (outlier neutral) other comprised 30 outlier loci. Results all analyses using both sets indicated high level genetic differentiation between specimens Mexico U.S East Coast. Using set, low but significant also found among U.S. Coast, with subtle break near North Carolina South border. Genetic differences along Coast spatially autocorrelated, indicating latitudinal gradient. observed likely due physical barriers Florida Stream current, while attributable isolation caused dispersal limitations local temperature preferences. results investigation can be better monitor manage elasmobranch.