Influence of abiotic factors on the fecundity and ecological plasticity of a freshwater prawn in estuary and river environments

Context Macrobrachium amazonicum is a freshwater prawn of socioeconomic importance in the Amazon region, whose growth, reproduction and fecundity vary according to the environment. Aims To determine which abiotic factors influence the size and fecundity of populations of M. amazonicum in estuary and river environments. Methods To do so, we captured a total of 255 ovigerous females, 181 from the estuary and 74 from the river, and measured temperature, total dissolved solids, turbidity, salinity, pH, dissolved oxygen and precipitation. Key results We found that turbidity, precipitation and dissolved oxygen explained the variation in M. amazonicum size, and that the estuarine females were larger and had more and smaller eggs than riverine females. Conclusions Precipitation, turbidity and dissolved oxygen were found to bedetermining factors for the ecological plasticity of M. amazonicum females in different environments. Implications Freshwater prawn species display different reproductive strategies for distinct environments, and understanding their fecundity is important to establish efficient management policies. In addition, this information should be useful to improve the cost–benefit ratio of freshwater prawn farming in the Amazon region.