Use of genetic markers in growth testing of common carp, Cyprinus carpio L., carried out over 2 or 3 year cycles

Abstract. A method of testing the growth of different genetic groups of common carp, Cyprinus carpio L., over 3 year cycles was demonstrated. In European aquaculture, attaining market weight of common carp usually requires growth periods of 3 years. Typical mean weights at the end of the first year are 20 to 40g. For genetic testing, each progeny is nursed in a separate first-year pond. Co-stocking these nursery ponds with samples of a genetically marked group of carp is a convenient method of multiple nursing for second- and third-year testing. This method does not require additional ponds for generating multiply nursed samples.
Four successive experiments were carried out using this method of testing. Each experiment was run over a period of 3 years. The modified multiple nursing method generated sufficiently large weight differences only in one experiment. In the others, weight differentiation was small and unreliable, or several multiply nursed groups were lost or unidentifiable. Some improvements of this method are suggested. The genetic groups participating in the test included Ropsha carp, an Estonian strain and a strain of German mirror carp. The results are consistent with a similar study involving Chinese and European races of common carp.