Abstract:
Growth, reproduction and mortality of the snakehead, Ophicephalus
striatus Bloch, inhabiting the Muthurajawela swamp, a low pH environment in
Sri Lanka, were studied using monthly samples collected by angling and
indigenous fish traps. The asympototic standard length and growth coefficient
were estimated to be 49.5 em. and 0.194 year" respectively. These figures were
smaller than those estimated for this species in other regions of the country. The
estimated total and natural mortality coefficients were 3.7'year-1 and 1.7 year "
respectively. The exploitation ratio was 0.5 and indicates that this stock
is exploited at the optimum level. The absolute fecundity of the fish
ranging from 23.8 em to 29.5 cm in standard length varied from 3800
to 10800 eggs. These figures are higher than those recorded for O. striatus
in other regions of Sri Lanka. The relative fecundity ranged from 19 to 38
eggs/g of body weight. The minimum size at maturity for the females and
males were 19.5 em and 24.5 em respectively. The sex ratio was found to
be 1 female : 3.6 males.
