Effects of age and size on
reproductive performance of captive Farfantepenaeus paulensis
broodstock
S. Peixoto, R.O. Cavalli, W. Wasielesky, F. D'Incao,
D. Krummenauer, Â.M. Milach-2004
Aquaculture, 238: 173-182
Abstract:
The performance of captivity-reared Farfantepenaeus
paulensis broodstock of different ages (10 and 16 months old) and sizes
were compared in two separate 30-day-long trials. For each trial, groups of
20 males and 30 unilaterally eyestalk-ablated females were stocked into two
10-m2 maturation tanks. Data on male quality (spermatophore
weight and sperm count), spawning performance, hatching rates and
metamorphosis to the first protozoa stage (PZI) were recorded. Histological
analysis of the ovary of ready-to-spawn females was also carried out. Older
males had significantly heavier spermatophores but these did not necessarily
contain a higher number of sperm cells. Size rather than age appears to have
a more important role in the regulation of the number of sperm cells per
spermatophore. Within the same age group, larger females had a superior
spawning performance than smaller ones. No significant differences in
percentages of fertilization, hatching and metamorphosis to the first
protozoa stage were detected. Similar to other studies with penaeids, our
results suggest that female size rather than age exerts a stronger effect in
determining the reproductive performance of F. paulensis. The present
study also demonstrates that 10-month-old F. paulensis females reared
in captivity and weighing 25 g or more may be successfully used for
reproductive purposes, although significant improvements on reproductive
output will be achieved if older (16-month-old) and larger (≥45 g)
females are used.
(Laboratório de Maricultura, Departamento de
Oceanografia, Fundação Universidade Federal do Rio Grande, C.P. 474,
96201-900, Rio Grande, RS, Brazil, e-mail: silviop@mikrus.com.br)