STOCK-SPECIFIC VARIATION IN SCALE MORPHOLOGY OF ATLANTIC STRIPED BASS

We examined scales of wild striped bass Morone saxatilis to determine whether scale morphology differs systematically among three Atlantic c oast stocks and thus could be used for stock discrimination. Morpholog ical variables investigated included Fourier coefficients, ratio shape descriptors (circularity, rectangularity), truss networks, perimeter landmarks, width and spacing of the first 10 circuli, and angular meas urements of the scale interior, A variable was considered potentially useful for stock identification if it could be corrected for size vari ation, did not show year-class effects, and showed significant stock-o f-origin effects in a multivariate analysis of variance. Fourier shape descriptors, rectangularity, and angular measurements of the scale in terior showed the greatest potential for discrimination of Atlantic st riped bass stocks. In addition, circulus patterns showed some usefulne ss. The remainder of the morphometric variables appeared less useful e ither because of failure to meet statistical assumptions for size corr ection (truss networks and perimeter landmarks), significant year-clas s effects (circulus patterns), or a paucity of significant stock-of-or igin effects (truss networks, circulus patterns, circularity). Relativ ely few strong correlations (r greater than or equal to 0.70) were evi dent among morphological variables of different types.