The effect of a genetically improved common carp stock on the productivity of pond ecosystem: Implication for selective breeding in nature-close conditions

Abstract

Aquaculture in Central Europe is mainly performed in man-made fishponds. Common carp (Cyprinus carpio), the main fish species, grows on natural food developing in fishponds and supplemental feeds (SF). Previously, it was found that common carp (CC) growth may be improved by selective breeding (SB). However, there is a question if such stocks could utilize the fishpond natural resources better and increase the mass yield per unit of water surface area. Otherwise, SB would be useless. In this study, we compared the production parameters of two mirror CC stocks (M2 and M2 x AMC) fed with two supplemental feeds (grain and carp plant-based pellets). The cross-bred M2 x AMC represented a model stock with higher performance potential comparable to a stock after several generations of SB for better growth. The study was performed in fishponds of Fish Farm Klatovy under their common practice over the three age categories of carp (CO – C3). Each mirror carp stock was reared separately with an internal scaly control group (CG) to evaluate potential environmental biases. Performance and production parameters between the two mirror carp groups and distributed SF were compared from a total of 43 fishponds using generalized linear models. It was found that the M2 x AMC showed remarkably higher overall mean individual weight gain (by 24.9%; 281 g vs. 351 g) and survival (by 16%; 46.6% vs. 54.4%). Moreover, fishponds stocked with the M2 x AMC displayed significantly higher (23.7 – 58.3%) mirror and total carp mass and mirror, total, standardized, relative and estimated carp mass yields, while the CG performed similarly in both groups of fishponds. No effects of the SFs on the production parameters were observed. Results suggest that SB for faster growth in common carp for a minimum of 3–5 generations should be manifested in a gradual increase of mass yields without changing the fishpond management.