Latitudinal and stock-specific variation in size- and age-at-maturity of female winter flounder, Pseudopleuronectes americanus, as determined with gonad histology

► Female maturity was examined from Delaware Bay, USA, to the Scotian Shelf, Canada. ► Mature fish spawned in spring, when up to 30% of the total body weight was gonad only. ► Along the coast, age-at-maturity declined with latitude; size-at-maturity was less variable. ► On Georges Bank, females matured at a larger size but at a modal age. ► These findings support existing stock units but highlight variation within these units.