Testing of performance in common carp Cyprinus carpio L. under pond husbandry conditions I:: top-crossing with Northern mirror carp

Performance tests of Northern mirror carp (M72) and three different crossbreds were conducted in semi-intensive pond conditions from the larval stage up to market size. The aim of this study was to evaluate the possible utilization of new hybrid combinations (M72 x PL - Pohorelice mirror carp) and (M72 x Dor - Israeli mirror carp), and to compare them with a hybrid widely reared as a commercial product (M72 x M2 - Hungarian mirror carp) and with M72 purebred. The testing model was derived from similar studies carried out in the conditions of the Czech Republic, where an internal control of different scale cover is used to eliminate all non-genetic effects. ANCOVA revealed at market size significantly better growth in M72 x Dor (1 619 +/- 28.3 g; LS mean +/- SE) and M72 x PL (1475 +/- 29.8 g) compared with M72 (1278 +/- 26.3 g). Survival during the test of 3 years duration was significantly the best in the M72 x Dor hybrid as were the dressing out parameters measured at market size, even if these were significantly different only in proportion of fillets with skin (39.1 +/- 0.28%). Interestingly, the crossbred M72 x M2 commonly used by Czech fishermen showed for both, growth (1371 +/- 26.2 g) and survival, the lowest values among crossbreds and with regard to dressing out parameters mostly among all tested groups.