Mach et al. (2011) found some regional differentiation correspondent to biogeographic provinces contrarily to previous assumptions of homogeneity (Johnson, 1975; Conover, 1998). Clark et al. (2010) also found differences in otolith chemistry. Stock structure of Atlantic silverside is not totally understood. Thus the Prince Edward Island where the unique Canadian fishery takes place is considered as a unit for assessment and management purposes (DFO, 1996; DFO, 1997; DFO, 2010).