Validating the periodicity of growth band formation and timing
of first increment formation is important for accurately characterizing
growth (Campana, 2001). While the abovementioned studies
have produced estimates of growth using various aging techniques,
the validation of growth bands as being deposited annually is
uncertain. The best attempt used edge type analysis (McBride et al.,
2008), which determined whether the most recently formed increment
had just begun, was intermediate or nearing completion.
While limited by small sample sizes for some months, the first
annulus was identifiable and each growth band was suggested
to represent 1 year of growth. Luckhurst et al. (1997) suggest
that daily increments are clearly visible at high magnifications in
sectioned wahoo otoliths. Therefore, in combination with otolith
staining techniques using mark-recapture methods successful for
other scombrids (Schaefer and Fuller, 2006), daily increments may
provide a more useful approach to age validation for wahoo.