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

Growth and density in freshwater crayfish are inversely related and this is compounded by Ž . 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 ponds and improving feed quantity or quality could reduce stunting. Male monosex populations grew on average 68% faster than female monosex populations and 53% faster than mixed-sex populations. Female yabbies in monosex culture grew 9% slower than Ž . Ž . males and females combined in mixed-sex 50:50 populations. Both males 17% and females Ž . 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 normal mixed-sex production. While growth in monosex and mixed-sex populations was improved Ž y2 y1. by either increasing feed rates of lupins 2.5 to 5 g m week or using a formulated diet, male monosex populations still grew faster. q 2000 Elsevier Science B.V. All rights reserved.