A comparison of mixed-sex vs. monosex growout and different diets on the growth rate of freshwater crayfish (Cherax albidus)

Growth and density in freshwater crayfish are inversely related and this is compounded by uncontrolled reproduction in growout ponds. Growth rates of yabbies (Cherax albidus) were compared in monosex and mixed-sex populations using three feeding regimes to assess whether preventing reproduction in p onds and improving feed quantity or quality could reduce stunting. Male mon osex populations grew on average 68% faster than female monosex populations and 53% faster than mixed-sex populations. Female yabbies in monosex cultu re grew 9% slower than males and females combined in mixed-sex (50:50) popu lations. Both males (17%) and females (31%) in monosex culture grew faster than males and females in mixed-sex culture. Stocking ponds with only male yabbies resulted in a 70% greater gross value of animals produced than norm al mixed-sex production. While growth in monosex and mixed-sex populations was improved by either increasing feed rates of lupins (2.5 to 5 g m(-2) we ek(-1)) or using a formulated diet, male monosex populations still grew fas ter. (C) 2000 Elsevier Science B.V. All rights reserved.