Genetic testing of common carp in cages. 1. Communal versus separate testing

Relative growth rates of different genetic groups of common carp (Cyprinus carpio ) were tested simultaneously in cages stocked with a given genetic group, and in cages stocked communally with samples of different genetic groups. A clear association between relative growth of different progenies, in communal and separate testing, was found in one of these tests. In cages, results from the convenient method of communal testing may serve as reliable predictors for relative growth of different genetic groups in separate testing. This should be confirmed in further, similar investigations. Previous tests in communally and separately stocked ponds generated a similar conclusion. On the other hand, genotype-environment interactions have been demonstrated when the same genetic groups were tested simultaneously in communal ponds and cages. This means that relative pond performance is not a reliable predictor for performance in cages, or vice versa.