TilE USE OF MINUTE EMllEDED SCALES FOR AGE DETERMINATION OF THE MEDITERRANEAN SEA SIGANID: Siganus rivulatus FORSKAL.

TilE USE OF MINUTE EMllEDED SCALES FOR AGE DETERMINATION

OF THE MEDITERRANEAN SEA SIGANID:

Siganus rivulatus FORSKAL.

KH. A. HUSSEIN

Institute of Oceanography and Fisheries. Alexandria, [9ypt.

ABSTRCT
The embeded minute scales of Siganus rivulatus were
Investigated and succefully used for age determination.
Original scales which carry the all formed “year marks”
were encountered in the most posterior body area. Anterior
and mid areas did not bear all the classical “year marks”
and could not be used for age determination. Scales formation
did not start at once, the posterior area, in contrary
to many other fish species, may virtually secrete the first
scales on the body. Up to five “year marks” could be
interpreted on the posterior scales, and “real year mark”
was identified. Annual growth of S1ganus rivulatus was
estimated by “back calculation” and shown to be decreased
as the fish aged.