The shrimp aquaculture industry faces several problems,
including contamination caused by farm effluent. Polyculture
appears to be an adequate alternative to minimize or
eventually solve these problems. However, polyculture is
not commonly used in the shrimp industry. There are
three general types of polyculture: direct, cage-cum-pond
and integrated polyculture. Each one with two variants:
monotrophic and multitrophic.
Shrimp polyculture is a promising industry and has been
shown experimentally to improve yield, decrease the environmental
impact, re-utilize wastes and reduce the incidence
of pathogen organisms in shrimp aquaculture. In
addition, different by-products with a commercial value can
be obtained from the subordinate species. However, there
are problems and considerations that need to be solved
before practicing polyculture, such as economic and human
effort investment, compatibility of the species (feeding habits
and environmental requirements), food competition,
space, size of the organisms and decreasing oxygen levels.
Many species from different trophic levels, such as fish,
mollusks and plants, show aquaculture potential for use
as subordinate organisms in shrimp farming. However, it
is important that these species fit with the environmental
requirements of the shrimp.
Partitioning and multitrophic polyculture appears to be
the best option for this practice because possible antagonistic
activity among the species is diminished when they
are separated by different units or barriers (cages).
The design of the culture system should be cost effective
and provide an optimal environment for the species
that are being cultured to thrive. However, further
research is needed in this field that examines new species,
densities and systems. It is also necessary to make aware
and to encourage farmers to try this activity to reduce the
environmental impact resulting from effluent discharge.