| When
most folks in southern Louisiana think of crawfish production,
the vision of a flooded rice field comes to mind. It is
a common belief that crawfish derive their greatest nutritional
needs from the remaining rice stubble after the grain has
been harvested. While this is true to some degree, it’s
the ecosystem and its food chain created by flooding harvested
rice stubble which makes crawfish production in rice fields
so prolific.
Crawfish
will eat almost anything including living and decomposing
vegetation, seeds, algae, microorganisms, and a myriad of
aquatic insects, invertebrates and small fish. Although
vegetation is the most abundant food source in crawfish
ponds, it is thought to contribute little to the direct
nourishment of crawfish. Nutrition comes from the microbial
rich organisms found colonizing dead and decaying plant
and animal matter (detritus) in aquatic environments. While
detritus sustains most natural, aquatic food chains, the
really high quality protein and energy rich foods required
to maximize crawfish production comes from consuming animal
matter such as insects, insect larvae, worms, snails, fish,
etc. These organisms are commonly found in detrital rich
aquatic environments.
Therefore,
rice fields with lots of stubble can sustain this food chain
for longer periods into the spring growing season, allowing
for maximum crawfish growth and production. What makes rice
more suitable for crawfish ponds over other vegetation types
is its erect or upright posture even in standing water.
This prolongs the detritus cycle by slowly dropping leaves
and falling of stems into the water through the winter and
into spring when the fast growing crop of crawfish need
it most.
Obviously,
many other factors come in to bear on the productivity of
a crawfish pond, such as population density, water quality
and weather conditions. There are no guarantees that a good
crawfish crop will be produced with ample stubble. However,
a crawfish farmer can increase his odds by starting with
a good stand to jump start the detrital cycle.
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