| Abstract: | Polyculture of fish has been shown to be an effective means of increasing production beyond that achieved in monoculture, but little research has been conducted to evaluate the effect of polyculture on production of shrimp species. This research was designed to investigate performance of Penaeus vannamei (v) and P. stylirostris (s) in monoculture (treatments 100v and 100s) as well as in polyculture at various species ratios (75v:25s, 50v:50s, and 25v:75s) at a constant density of 1.8 × 105 /ha. Shrimp were stocked into fifteen 0.1-ha ponds at the Texas A&M University Mariculture Facility for 123–134 days. Results indicate a higher mean survival rate (73 vs 22%) but lower mean growth rate (0.09 vs 0.14 g/day) of P. vannamei than P. stylirostris. Survival rates of neither species differed significantly among treatments. Final weight of each species significantly decreased with increasing density of the same species but significantly increased with increasing density of the other species. Best growth of both species occurred in the 75v:25s treatment. Observed differences in distribution and diel activity of the two species within ponds may partly explain the compatability of these two species in polyculture. Production rates (range, 690 to 2,180 kg/ha) and value (range, US$2,720 to US$5,740/ha) among treatments generally increased with increasing composition of P. vannamei; however, no significant difference in mean value was detected between the 100v and 75v:25s treatments. As a secondary objective of this study, performance of shrimp (25v: 75s treatment) in a single-phase pond system was compared to that in a three-phase (nursery, intermediate, and grow-out) system. Survival, growth, production, and value were found to be similar between systems. |
