Hatchery, Nursery, Nutrition and Stock Evaluation of Redclaw Crayfish Cherax quadricarinatus
Type of Degreedissertation
Fisheries and Allied Aquacultures
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The redclaw crayfish (Cherax quadricarinatus) aquaculture industry has developed rapidly in tropical and subtropical regions of the world during the last decade. Important advances have been made; however, technology for commercial production is still in its infancy and still faces major challenges. With the purpose of improving economic viability and overcome these challenges, a series of hatchery, nursery, nutrition and stock evaluation experiments were conducted. Research was conducted at the AGY hatchery property of Megar S.A. de C.V in Soto La Marina Tamaulipas, Mexico and at the E.W Shell Fisheries Center, Auburn University, Alabama between May 2007 and August 2008. Nutrition studies demonstrate that soybean based diets formulated to contain 36% protein and 7% lipid maintaining an adequate amino acid profile can use fish meal, poultry by-product meal, distiller’s dried grains with solubles or ground pea meal indistinctly as alternative sources of protein without negative effects on growth, yield or survival of the crayfish. Experiments also suggest that the addition of stargrass (Cynodon nlemfuensis) at a rate of 125 kg/ha/wk in combination with a properly balanced pelleted feed for juvenile redclaw can reduce feed inputs and, thereby, reduce feed costs for redclaw producers. The hatchery-nursery techniques used in these experiments recommend that water volume has minimal effect on the production performance in a redclaw hatchery-nursery system. Surface area is the best way to account for juvenile production of redclaw. Juveniles from female densities between 4.2 and 6.9 females/m2, averaging approximately 80 g/female, with a 30-day nursery period appear to provide the best results in a commercial hatchery-nursery, when compared to lower and higher densities of juveniles and 20 and 40-day nursery periods. During the stock comparison studies, when comparing the best two stocks identified by Australian and Mexican farmers, results imply that there is no significant differences in growth performance between the Walkamin (Australia) and the Megar (Megar) stocks. The experiments conducted in this study have increased the general knowledge and understanding of the redclaw crayfish, C. quadricarinatus.