Influence of density on growth and survival of freshwater prawn macrobrachium americanum (Bate, 1868) (Caridea: Palaemonidae) cultured in a cage-pond system

The domestication and culture of freshwater shrimp native of tropical and subtropical American Pacific zone requires the study and development of technologies in open systems where their response to types of farming, feeding and management strategies generate practical information for the production of this species. The aim of this study was to evaluate the effect of stocking density on growth and survival in M. americanum juvenile-adult, cage-cultured and to determine the optimal density for grow-out production. The caridean shrimp Macrobrachium americanum was cultured for 152 days in a 16 cage-culture (3 m³ each) at densities of 1, 3, 6 and 9 org/m³, respectively, with stocking sizes from 12.1 ± 1.7 to 13.5 ± 2.3 g. The prawns were fed twice daily with Camaronina 35%. Water quality parameters were within standard range for caridean shrimp culture. There was a significant effect of density on final weight, growth rate, specific growth rate, K condition and survival, and an inversely proportional relationship with the feed conversion ratio. The growth was affected by density, resulting to a maximum increase of 6 org/m³ in the asymmetry of the prawn and also increasing the number of small organisms by 9 org/m³. However, it is necessary to study such aspects as the rate and frequency of feeding, the initial size-grade and the implementation of shelter, among others.