Clean, non-regenerated scales should be chosen. The thickness of the laminate should be enough to accommodate the relatively thick scales of large weakfish. If too thin a plastic is used, information on the thinner anterior edge may be lost. Scale impressions are generally examined on a standard microprojector at a magnification of 32x, although this can be modified depending on the scale size. Scales are characterized by distinct radii emanating from the focus to the anterior edge, and prominent circuli in the lateral fields.
Annual marks appear as thin, opaque, broken lines and are most distinct in the radii zone.
One distinctive feature of the annuli is the shape or lack of circuli in the thin band. Unlike some fish scales, such as haddock, the annuli appear as an abrupt stoppage or change in growth. This is followed by immediate resumption of regular growth, as opposed to a gradual change. In assigning an age to an individual fish, the researcher should be aware of advantages in using a standardized 1 January birthdate. Weakfish are somewhat unusual since the annulus is formed in late spring, at the same time that spawning occurs.