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Crawfish Production: Harvesting

by the Fish Site Editor
16 January 2006, at 12:00am

Crawfish Production: Harvesting - Robert P. Romaire, W. Ray McClain and C. Greg Lutz and published by the Southern Regional Agricultural Center and the Texas Aquaculture Extension Service - Freshwater crawfish of the genus Procambarus are a valuable aquaculturecommodity in the southern U.S., with annual production of 30 to 50 million pounds and farm-gate values of $25 to 50 million. Crawfishare produced on more than 120,000 acres, with more than 90 percent of it in southern Louisiana.

Crawfish Production: Harvesting - Robert P. Romaire, W. Ray McClain and C. Greg Lutz and published by the Southern Regional Agricultural Center and the Texas Aquaculture Extension Service - Freshwater crawfish of the genus Procambarus are a valuable aquaculture commodity in the southern U.S., with annual production of 30 to 50 million pounds and farm-gate values of $25 to 50 million. Crawfish are produced on more than 120,000 acres, with more than 90 percent of it in southern Louisiana. Southern Regional Agricultural Center

Unlike fishes, crawfish are not harvested by seining. Instead, crawfish are harvested with a passive system that uses baited traps. Harvest begins as early as mid- November in the deep South and continues through April to June. If fall and winter production of juveniles is low, and in areas farther north, harvest seldom begins before March and often continues into late July.

Crawfish are harvested frequently during the season. They may be harvested from well-managed ponds 40 to 90 days per year. In the deep South, two-thirds of the crop is usually harvested from March through June when densities of marketable crawfish are highest and crawfish are most active.

Trapping is labor intensive and accounts for more than half of the total production expense. Bait and labor are the major costs (Table 1). Efficient harvesting is essential for crawfish farming profitability.

Factors influencing crawfish catch and harvest size

The crawfish catch from production ponds often varies 2- or 3- fold from day to day (Fig. 1). Catch is influenced by many factors, primarily water temperature and the density of marketable crawfish. Other factors are water quality, type and quantity of vegetative forage, weather, lunar phase, and crawfish reproduction, growth and molting patterns. Table 2 summarizes the major factors affecting crawfish catch. Size at harvest is influenced more by environmental conditions than by genetics. Crowding reduces growth and can cause stunting.

Crawfish are aggressive and territorial, so larger crawfish intimidate and out-compete smaller individuals. Crawfish should be harvested soon after they reach marketable size. This removes larger individuals from the population, reducing aggression and leaving space and food resources for undersized animals. The minimum marketable size for crawfish varies with season, abundance and price; however, consumers prefer a count of 23 individuals per pound and larger (i.e., 3 1/2 inches and larger). Large crawfish, 10 to 15 count per pound, usually command premium prices.

Traps

For years, most crawfish traps were made of 3/4-inch, plastic-coated, hexagonal mesh wire (poultry wire), 19 or 20 gauge. This mesh retained crawfish of minimum marketable sizeabout 3 inches and longer (35 count per pound). Although these traps are still used, most new traps are made of 3/4- inch welded square mesh wire. The square mesh wire is more durable and retains smaller crawfish, thus increasing yield. The small crawfish can be a problem for buyers and processors, however.

The pyramid trap, with three entrance funnels, has become the industry standard (Fig. 2). Optional cylindrical extensions, usually 6 inches long, can be added to increase the height of the trap for use in deeper water. A 6-inch-diameter plastic pipe (or extruded collar) is placed at the top of the trap to function as a handle and to prevent crawfish from escaping through the open top. Most traps are made from 24-inch-wide by 44-inch-long or 24- inch-wide by 54-inch-long wire. The overall dimensions of traps are about 17 inches wide at the base and, with a 6-inch extension, about 26 inches tall.

The inside diameter of entrance funnels is usually 1 3/4 to 2 inches. Because wind, waves and avian predators (herons and egrets) that perch on the plastic extensions can cause traps to topple, metal supporting rods (5/16 inch diameter) are often added for stability. Crawfish traps do not have bait protection containers as do crab or lobster traps because they reduce the catch.

Baits

Traps must be baited to attract crawfish. Bait accounts for nearly onethird of total production cost. The cost of bait depends on the type used, amount used per trap, trap density, and trapping frequency. The two types of bait used are natural fish baits and formulated baits. Fish baits are usually sold frozen in 80-pound or 100-pound boxes. Clupeid or sardine-like fishes, specifically gizzard shad and Gulf men-haden or pogy (Fig. 3), are the most widely used natural baits in Louisiana where there are commercial fisheries for both species. They can be difficult to obtain in commercial quantities in other southern states. Herrings, common carp, suckers, and catfish and buffalofish heads are also used. Shad, menhaden and carp attract crawfish better than other natural fish baits. Beef pancreas (beef melt), commonly used by recreational trappers, is an effective attractant but too expensive for commercial use.

Formulated crawfish baits, often referred to as artificial or manufactured baits, were commercialized in the early 1980s and are produced by several feed companies. These cylindrical pellets contain mostly cereal grains, grain by-products, commercial flavoring agents, and a binder. They are usually 1/2 to 2 inches in diameter and 1 1/2 to 3 inches long (Fig. 3) and are sold in 50-pound bags. Some companies offer different formulations for use in cool or warm water.

The availability and price of fish baits are seasonal and they are more expensive than formulated baits. Large farms may have freezers or coolers for storing bait, but smaller farms require daily deliveries. The swimbladder of each fish must be punctured so it will sink, and it must be cut into efficient sizes. This labor adds to the cost. Formulated baits do not require refrigeration and are easier to handle.

Further Information

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Source: Southern Regional Agricultural Center and the Texas Aquaculture Extension Service - Taken from site - January 2006

the Fish Site Editor