to follow

Louisiana scientists test "forage varieties" for rice-crawfish farming

By TOM HARGROVE

Rice and crawfish go together—and not only in jambalaya and etouffee. Most crawfish farmers also grow rice. Both crops require ponded fields and water control, and its semi-aquatic nature makes rice the main forage crop for crawfish

But ironically, the best rice varieties for grain production aren't necessarily the best for crawfish, says Dr. Ray McClain, aquaculturist at the Louisiana State University Rice Research Station, Crowley. The highest-yielding rices mature early, are short, and have a high grain-to-foliage ratio. But crawfish farmers often prefer the older rice varieties for opposite traits.

The older varieties, taller than most newer rices, produce more foliage—crawfish forage. Tall varieties can also withstand deeper flooding; crawfish fields are usually kept 12 to 18 inches deep. Older varieties generally mature later, producing forage longer into the winter.

Most crawfish production is in rotation with a commercial rice crop. But some farmers with permanent ponds plant rice strictly for crawfish forage, and don't harvest the grain. For them, forage, to carry crawfish through the winter, is the most important product.

"It's like planting forage to take beef cattle through the winter, into the spring," says Dr. Steve Linscombe, LSU rice breeder. Mars, a tall variety bred in Arkansas in the late 1970s, is considered "the crawfish standard," Linscombe says.

World Collection screened

McClain and Linscombe are testing rice varieties strictly for use as a crawfish forage crop. The LSU scientists have screened the entire USDA World Rice Collection—more than 16,000 varieties--since 1994.

Three main traits are sought: high forage production; cold tolerance, so the plants will grow until late in the fall, and start regrowth early the next spring; and the ability to regrow vigorously from underwater stubble in the spring,

"Although we don't look for grain yield, we must remember that seed must be multiplied for any variety used for crawfish production," Linscombe says.

The three most promising rices are Taino 38, from Taiwan; New Guinea, from Fiji; and Long Guar Jim, a Chinese variety once grown in Hawaii.

Last year, Linscombe and McClain compared crawfish production on Mars with each of the three newly identified "crawfish rices." Four half-acre ponds of each variety were grown. Crawfish production on all three rices was higher than on Mars, Linscombe says. The crawfish rices also produced more larger, high-value crawfish.

The three crawfish rices survived winter temperatures in the low 20s, and regrew rapidly in the spring, Linscombe says. "By late May, only water was visible in fields planted to Mars, but these varieties were still producing forage."

Crawfish in Louisiana

Louisiana claims to be "head and tails" above the rest of the world in crawfish production, with more than 115,000 acres of crawfish ponds, and more than 500,000 acres of rice.

Pond yields were about 200 pounds per acre when commercial crawfish farming emerged as a Louisiana industry in the 1960s, but are 700 to 1,000 pounds today. The state's commercial ponds produce 75 to 105 million pounds yearly. Louisiana's "wild harvest"—crawfish gathered from bayous and rivers—ranges from 40 million to 70 million tons annually, and makes up 35 to 65% of total production.

Most Louisiana crawfish are consumed within the state, but the recent popularity of Cajun cooking is creating new national and international markets. From 4 to 5 million pounds are exported yearly to Sweden.

"Swedes have been eating crawfish longer than we have," McClain says. "In Sweden, a festive, party atmosphere revolves around crawfish."

But a fungal disease—called "crawfish plague"—almost wiped out the Swedish and Finnish crawfish populations around the turn of the century. Turkey had supplied Swedish crawfish lovers—until the same disease appeared there. Now, U.S. crawfish and some from China are almost the only exports available.

"Our exports to Sweden are cooked and packaged according to their style—in a dill solution," McClain continues.

A Cajun crawfish history…

Crawfish have been around only since 1775, according to a Cajun history published on the web page of Fruge Aquafarms, a Crowley, Louisiana, crawfish farm:

"…it all started when the French living in Acadie, Nova Scotia were expelled from their land by the British…[and]…traveled across North America to arrive in South Louisiana. People up in Nova Scotia really liked lobster. So it was only natural that…they brought their lobster with them. The problem was that the lobsters lost their appetite along the way and shrunk up quite a bit. Since this smaller lobster didn't really look like a lobster any more, the Acadians, now known as Cajuns, called this small crustacean a crawfish."

The internet history concludes with: "According to Thibodeaux Comeaux, a rice farmer in Ville Platt, this story is true."