Effects of age and size on reproductive performance of captive Farfantepenaeus paulensis broodstock

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-m(2) 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 (greater than or equal to 45 g) females are used. (C) 2004 Elsevier B.V. All rights reserved.