The influence of water renewal rates on the reproductive and molting cycles of Penaeus paulensis in captivity

摘要

The present study analyzed the reproduction of wild-caught Penaeus paulensis in relation to its molt cycle. The experimental design consisted of two treatments (continuous water flow and batch renewal) with two replicates. The stocking density in experimental tanks (1.50 x 0.96m) was approximately 7 animals/m2, resulting in 4 males (23.9 ± 2.3 g) and 6 females (52.0 ± 5.5 g) per tank. Shrimp had their uropods cut for individual marking and female maturation was induced through the unilateral eyestalk-ablation. The intermolt period of females and males (17.4 ± 3.2 and 17.8 ± 4.6 days, respectively), number of days between molting and the first spawn (6.9 ± 2.8 days) and number of spawns in the intermolt period (1.4 ± 0.5), presented no significant differences (P>0.05) between treatments. No influences on molt cycle or reproductive performance parameters could be related to differences in water quality parameters, especially nitrogenous compounds, suggesting a trend towards reduce water exchange in shrimp maturation. However, a relative decrease in the number of eggs per spawn was observed. This possibly was due to the smaller maturation tanks. The results of P. paulensis molt cycle could be useful for accompaniment and better planning of the reproduction in captivity.