MORPHOLOGICAL VARIABILITY OF GRASS CARP CTENOPHARYNGODON IDELLA (VALENCIENNES, 1844) IN RESERVOIRS OF SOUTHERN KAZAKHSTAN

The article presents the study results of the inter-population variability of morphometric features of grass carp in the natural reservoirs of southern Kazakhstan (the Ili Delta and the Kapshagai Reservoir) and in the Kapshagai spawning and breeding farm. In the compared populations of herbivorous fish there has been found the variability in meristic characteristics to varying degrees, as well as the proportions of individual body parts. The increased value of inter-population variability may indicate the high plasticity of morphological features of grass carp and the significant adaptive capabilities of the compared populations. The valid differences in grass carp samples marked by a group of morphological features (plastic and meristic) and taken of fish from the hatchery and natural reservoirs of the Balkhash-Ili basin indicate the existence of species produced by artificial reproduction and by natural spawning in the natural reservoirs.