Frequent Handling Adversely Affects the Growth of the Australian Freshwater Crayfish3, Cherax destructor

Abstract

Biomass of Cherax destructor was redetermined in each of 10 tanks at different time intervals for adjustment of feeding levels and the frequency of handling events correlated with FCR, SGR, weight gain, mortality rate, and damage measured as claw loss. The treatments sampled most frequently showed the lowest increases in total biomass, the poorest food conversion ratios, and the lowest specific growth rates, even though food inputs were matched more carefully to the biomass for these treatments. From the study, it may be surmised that the process of sampling itself and the increased frequency of behavioral interactions that occurred afterwards adversely affected growth, perhaps by stressing the animals. A minimal time period between sampling is suggested for C. destructor.

Key Words:

• Crayfish
• yabby
• Cherax destructor
• growth
• stress
• handling