Theses and Dissertations


Title: Polyculture of the Australian red claw crayfish (Cherax quadricarinatus) and male tilapia

Name: Courtwright, Corey

Degree: MS

Chair: David B. Rouse

Resides:

University: Auburn University

Location: Auburn, Alabama

Date: 2004

Pages: 53

Keywords: Australian red claw crayfish, Cherax quadricarinatus, male tilapia, polyculture, Oreochromis mossambicus, Oreochromis niloticus, FCR

Abstract:

Polyculture of Australian red claw crayfish (Cherax quadricarinatus) and red, all-male hybrid tilapia (Oreochromis niloticus X O. mossambicus) was evaluated using 0.02-ha earthen ponds. Red claw with an average weight of 15 g were stocked into 9 of 12 ponds at a density of 4/m2. Three of these ponds were used for a red claw-only control treatment. Three ponds had 1-m3 cages each stocked with 100 tilapia. The remaining three red claw ponds were also stocked with 100 tilapia each that were not confined to cages. A final three ponds were stocked with 100 free-swimming tilapia as a tilapia-only control. Tilapia averaged 130 g at stocking. Tilapia were fed a floating 32% protein diet, and the red claw received a sinking, 36% protein commercial shrimp feed. After 115 days of culture red claw survival, yield, - and feed conversion ratios were not significantly different among treatments. However, red claw harvest weights were different. Red claw cultured with free-swimming tilapia were significantly smaller than the red claw in monoculture or when cultured with caged tilapia (39.3 g, 58.5 g, and 58.3 g, respectively). Tilapia showed significant differences in weight, yield, and FCR among the treatments. There was apparently interaction between red claw and tilapia, if tilapia were allowed to swim freely in ponds with red claw. However, when tilapia were caged there was no difference in red claw growth or survival when compared to red claw cultured in monoculture. Partial budget analysis further demonstrates the negative impacts of free-swimming tilapia. Caged tilapia with red claw showed an increase in returns over red claw monoculture, while red claw with free-swimming tilapia showed a decrease in returns over red claw-only ponds.

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