Those researchers developed a new rice variety called "Ecrevisse," which is French for crawfish.
That new variety from the LSU AgCenter provides more biomass – or vegetation – throughout the crawfish season than those currently grown, according to AgCenter regional director Steve Linscombe, who also is one of the developers of Ecrevisse. That, in turn, leads to more sources of food for the crawfish.
Linscombe explained that Ecrevisse is intended for crawfish farmers who raise crawfish in monoculture – where the ponds are used for raising crawfish only rather than double-cropped with rice that is first harvested for grain.
"Farmers who double crop stock their crawfish in a rice pond after the rice crop is planted," Linscombe said. "After they harvest the rice, they flood the fields again. The stubble and whatever regrowth comes from it provide the basis for a food web that feeds the crawfish."
While rice is an important part of the crawfish food chain, crawfish really don’t feed on it, explained Ray McClain, an aquaculture researcher at the LSU AgCenter Rice Research Station.
Decaying green plants, such as rice, provide the food for insects and small water organisms that make up the bulk of the crawfish diet, McClain said.
But one of the drawbacks of rice varieties grown for grain is their susceptibility to "winterkill" – which means they don’t grow back in the spring.
Ecrevisse, on the other hand, "has better cold tolerance and can have regrowth in the spring to produce good vegetation that provides the environment where crawfish thrive," McClain said.
Linscombe said farmers who raise crawfish in monoculture often continue harvesting the mudbugs well into summer and, without good vegetation, the crawfish stop growing and remain stunted.
Field trials with Ecrevisse as part of the crawfish’s food chain produced more large, high-value crawfish than did fields with common rice plants, McClain said.
The new rice variety should improve productivity of ponds devoted to raising crawfish exclusively, Linscombe said. "I think under commercial conditions, the use of this variety may actually produce higher yields of crawfish."
Foundation seed of Ecrevisse is available from the LSU AgCenter’s Rice Research Station. More information is available from Larry White, manager of seed programs, at (337) 788-7531 or [email protected]
Rick Bogren is a writer for the LSU AgCenter.