Aj. Fowler et al., Reproductive mode and spawning information based on gonad analysis for theKing George whiting (Percoidei : Sillaginidae) from South Australia, MAR FRESH R, 50(1), 1999, pp. 1-14
The reproductive biology of the King George whiting, Sillaginodes punctata,
was investigated for populations at two localities in South Australia. Ana
lyses involved determination of gonadosomatic indices, macroscopic staging
of gonads, size frequencies of oocytes, spawning fractions of females, and
batch fecundities that were related to fish size and age. Size-frequency di
stributions of oocytes, measured from histological slides and whole preserv
ed oocytes, were multi-modal but were continuous amongst development stages
. All development stages of oocytes co-occurred in some gonads, and hydrate
d oocytes and post-ovulatory follicles also co-occurred. Such characteristi
cs suggest that the King George whiting is a multiple batch spawner with as
ynchronous development and indeterminate fecundity. Spawning occurred at le
ast through the months of March-May, with a peak in April. On one occasion
spawning occurred in the early afternoon on a flooding tide. Fish ranged in
age from 3 to 17 years, and most, regardless of sex or size, showed active
gonad development. Estimates of batch fecundity ranged from 5250 to 152191
hydrated oocytes per ovary, and were linearly related to fish weight and l
ength, but less well to age. The linear relationships between batch fecundi
ty and fish size differed significantly between the two localities.