Production of Penaeus monodon (Fabricius) using four natural food types in an extensive system

Abstract

Growth, survival, and production of P. monodon feeding on four types of natural food, i.e., lablab (benthic mat of cyanobacteria, diatoms, and associated fauna), Ruppia maritima, lumut (filamentous green algae and attached organisms entangled in the water column and on the bottom), and plankton, were evaluated in ponds in Iloilo, Philippines. The gut content of shrimp was analyzed and the flow of the food web was traced using stable carbon isotope (δC) analysis. Twelve 500-m² ponds were stocked with juvenile shrimp (average weight 0.8 g) and grown for 3 months at the rate of 4000 ha⁻¹. In Ruppia and plankton ponds, the shrimp attained 91–92% survival, and in lumut and lablab ponds, 76–80%. Total shrimp production in Ruppia and plankton ponds was 114 and 129 kg ha⁻¹ crop⁻¹, while lumut and lablab ponds yielded only 59 and 85 kg ha⁻¹ crop⁻¹, respectively. The δC analysis of all treatments was not significantly different, indicating that a common food (detritus), as shown by the gut content analysis, appears to be the most significant food resource of shrimp in this study. Shrimp foreguts from all the treatments consisted of detritus (non-living particulate matter), copepod/animal remains, diatoms, cyanobacteria, and green algae. Detritus ranked highest in frequency of occurrence, followed by copepod/animal remains.