The study of Spondyliosoma cantharus (L.) reproduction was carried out with
in the framework of a project on the Fisheries resources of the south-west
coast of Portugal, and was based on the analysis of the spawning season, go
nad maturation, size-at-maturity, fecundity, and hermaphroditism. Spawning
took place from February to April, peaking in March. Analysis of the sex ra
tio by size class and season showed that females were more abundant through
out the year (M/F=0.57) and in the smaller size classes. Overall size at fi
rst maturity (L-50) was 20.10 cm total length (TL), with a significant diff
erence between males (22.41 cm, TL) and females (19.98 cm, TL). Absolute fe
cundity (Fa) ranged from 37,506 to 112,074 oocytes, with a mean of 61,396.
A power type relationship best described the relationships between absolute
fecundity and TL (Fa = 436.27TL(1.575)), and somatic weight (Fa = 2979.7SW
(0.585)). The number of oocytes/g of female somatic weight ranged from 217
to 549, with a mean of 346. The reproductive strategy of this species is ch
aracterised by protogynic hermaphroditism, as indicated by the presence of
individuals in transition and of testes with vestiges of preceding ovaries
associated with the significant differences in the size frequency distribut
ions of the sexes.