Technical and biological evaluation of Galician carp young-of-the-year in the conditions of industrial rearing in the ponds of Subcarpathia

Purpose To analyze technical and biological parameters of Galician carp young-of-the-year in the conditions of their commercial rearing in Subcarpathia ponds. Methodology. The works have been performed in accordance with conventional techniques in fish farming and selective breeding. During the rearing of Galician carp yearlings, a monitoring of abiotic factors in the experimental pond has been carried out. Findings. According to hydrochemical analysis, pond water belonged to hydrocarbonate class of calcium water and a type, which is typical for natural waters of this physical-geographic area. The species composition of phytoplankton at the beginning of the study was represented by 39 species and intraspecific taxa, in the middle of the experiment — 33, and 36 species and intraspecific taxa at the end of the study period. The majority of phytoplankton species composition was represented by green algae. The majority of zooplankton biomass (up 46%) was represented by copepods, while rotifers dominated by abundance (up 49.9%). The parameters of zoobenthos development in the rearing pond ranged within 54 - 120 ind. / m2 by abundance and 0.5 - 1.3 g / m2 by biomass. The most abundant zoobenthic organisms were Chironomidae (71%) and Oligochaeta (29%). Fish stocking density in the rearing pond of the 1st order was 10 thousand fish/ha; fish seeds were represented by Galician carp larvae. At the end of the growing season, 27.2 thousand young-of-the-year were obtained, the survival rate was 68%. Mean individual weight was 96 ± 75 g, coefficient of variation was 12%. When assessing the dynamics of weight growth, its peak was observed in the first week of August, while the specific growth rate had maximum values in the third week of July. Exterior parameters were used to evaluate strain characteristics. In the middle of the growing season, the young-of-the-year had mean condition factor of 2.6 ± 0.3, which was high enough for them. Before wintering, this value increased to 3.0 ± 0.2. The head index at the beginning of the growing season was 4.4 ± 0.7, at the end of the growing season it decreased to 3.3 ± 0.1. The body depth index index ranged from 2.5 ± 0.1 to 2.6 ± 0.03. The body girth index was 1.1 ± 0.1. The caudal peduncle ranged from 1.9 ± 0.2 to 1.4 ± 0.2, while the coefficient of variation was 15% to 18%. According to the obtained results, the technical parameters of Galician carp young-of-the-year were higher than normative values. Originality. For the first time we evaluated the basic technical and biological parameters of Galician carp young-of-the-year. The assessment of exterior parameters of the study object during the growing season was provided. The evaluation of Galician carp young-of-the-year in the conditions of commercial rearing in Subcarpathiaт ponds was performed. Practical value. Industrial cultivation Galician carp young-of-the-year will provide an opportunity to produce high-quality material for further production of age-2 fish as well as will allow increasing fish productivity parameters in pond fish farms in the Subcarpathiaт region.