Selection for faster growth in the freshwater crayfish Cherax destructor

The freshwater yabby, Cherax destructor, is native to south-eastern Australia and has been the basis of a small aquaculture industry since the early 1970s. However, despite the long period of culture the industry has never matured into a large-scale aquaculture producer. One of the suggested reasons explaining why the industry has not developed as expected is that inferior animals are presently being farmed. As a consequence a program was started in 1998 aimed at increasing the productivity of yabby aquaculture through genetic improvement. This program was based on founder stock from two populations previously identified as having good traits for aquaculture and involved a within-family selection protocol, coupled with a circular mating strategy, to select for faster growth rate (i.e. weight at age). A control line was also maintained to estimate the rate of genetic response. After two generations of selection, males and females from the selected families were 29.5% and 32.7% heavier than controls, respectively. This represents an average genetic gain per generation of ∼15.5%. It is concluded that a within-family selection strategy is very effective in increasing growth rate in this species.