The present study demonstrates the effectiveness of the protocol used to enhance
natural productivity in shrimp ponds. Shrimp consumed zooplankton, benthos, and
phytoplankton throughout the 14-week experiment.
The stocking density was 20 individuals/m2
, lower than the 50/m2
specified for shrimp
aquaculture on an intensive scale (Mena-Herrera et al., 2006), but similar to commercial
farms working on a semi-intensive scale, where the enhancement of natural productivity
before and during culture is possible. In addition and also similar to commercial farms,
artificial feed was not limited. Shrimp in the enhanced ponds showed a marked
preference for natural food. In the unenriched ponds, natural food was observed in the
stomachs of all shrimp whereas not all stomachs contained artificial feed. The preference
for natural food could indicate that artificial feed can be reduced if natural productivity is
enhanced. The stomach contents indices suggest that high densities of natural food
enhance the feeding activity of shrimp. A higher proportion of full stomachs and lower
proportion of empty ones were observed in shrimp from the enhanced ponds where
natural food was abundant. “At some point” in the growth process of white shrimp, a
change in feeding preference can occur, during which growth is supported mainly by
nutrients from natural productivity (Gamboa-Delgado et al., 2003). The higher amount of
empty stomachs in shrimp from unenhanced ponds could be associated with the lower
natural productivity and a change in feeding preference.