Hybridization in Australian freshwater crayfish - production of all-male progeny.
In freshwater crayfish aquaculture high densities can result from uncontrolled reproduction. Hence some farmers manually sex yabbies Cherax albidus and stock only male crayfish in farm dams or ponds. Although male-only yabby populations produce an estimated 70% increase in gross income, hand sexing is time consuming and prone to error. A hybridization experiment was performed at a laboratory in Perth (Australia) using freshwater crayfish from the yabby species complex, collected, during September and October 1995, from geographically isolated regions throughout Australia, revealed a hybrid between Cherax rotundus females and C. albidus males which consistently produces only male progeny. This was confirmed in 9 crosses of the 2 species. The reciprocal cross of C. albidus females×C. rotundus males produces both male and female progeny. The consistent production of only male progeny by hybridization has not been recorded previously for a crustacean.