Angler’s guide to The purpose of scale reading is to interpret
the age of an Atlantic salmon consistently from features on its
scales including determination of river-age and sea-age.
Definitions used in scale reading The following definitions
based apply to scale reading: - Focus - the point on the scale
that is in the centre of the concentric lines; synonymous with
nucleus. - Circuli (singular circulus) - circuli appear on the
surface of the scale as dark concentric lines; synonymous - Band
- a concentric region of the scale which is formed during a
particular time of year. - Winter band - a dark band thought to
be associated with slow growth during the cold period of the
year. - Summer band - a light band thought to be associated with
rapid growth during the warmer period of the year. - Winter
check - up to 3 wide-spaced circuli occurring within a winter
band. - Summer check - narrow-spaced circuli, generally fewer in
number than a winter band, occurring within a summer - Annual
zone - a concentric region