Effect of stoking density on the productivity parameters of young-of-the-year tench (Tinca tinca Linnaeus, 1758) grown in recirculation aquaculture system conditions
Authors:   Institute of Fisheries of the NAAS, Kyiv, Konopelsky R. , Kurinenko H. ,   Institute of Fisheries of the NAAS, Kyiv, Hrystyniak I. ,   Institute of Fisheries of the NAAS, Kyiv, Korilyak M. ,   Lviv Research Station of the Institute of Fisheries of the NAAS, Velykyj Lubin
Published: December 2024

Purpose. To characterize the productive and biological features of juvenile tench (Tinca tinca Linnaeus, 1758) grown in a recirculation aquaculture system and to select the optimal stocking density for intensive cultivation technology.

Methodology. The studuy was conducted at the incubation workshop of “Karpatskyi Vodogray” LLC using a recirculation aquaculture system. Two 0.96 m3 tanks were used for the study.The material for thestudy were tench juveniles obtained in hatchery conditions. The cultivation of young-of-the-year was carried out in two stages: cultivation for 28 days at stocking densities of 100 and 75 thousand ind./m3, with the repeatability for two years (Experiment I – 2021, Experiment II – 2022). Over the next 94 days, at stocking densities of 15 and 20 thousand ind./m3 (Experiment I – 2021) and 10 and 15 thousand ind./m3 (Experiment II – 2022). The data obtained as a result of the experiments was subjected to statistical processing in MS Excel 2016. The criteria for analyzing were their average value and standard error (M±m).

Findings. The study showed that when growing young-of-the-years in a recirculation aquaculture system, the most optimal stocking density at the first stage of cultivation was 100 thousand ind./m3.Reducing the stocking density to 75 thousand ind./m3 allowed increasing the survival rate of larvae by 2.0–2.5%, however, there was no clear effect on their growth rate. At the second stage, at a stocking density of tench juveniles of 10–20 thousand ind./m3, similar productive and biological parameters of young-of-the-years were obtained, while their yield from 1 m3 of pools ranged from 3.52 to 6.67 thousand ind./m3. Thus, at a larval stocking density of 15 thousand ind./m3, 4.86–5.13 thousand ind./m3 of young-of-the-year fish were obtained with an average weight of 5.1–7.6 g, with a survival rate of 78.0–82.1%, which ensured a fish production yield of 24.86 to 39.00 kg/m3. With a decrease in stocking density to 10 thousand ind./m3, the survival rate and body weight of young-of-the-years increased by 4.5% and 1.45 times, respectively, but the yield of young-of-the-years was only 3.52 thousand ind./m3.

Originality. For the first time in Ukraine, a comprehensive assessment of the growth of juvenile tench in conditions of a recirculation aquaculture system at different stocking densities for the main technological stages of cultivation was carried out.

Practical Value. The results obtained allow us to demonstrate the effectiveness of applying new technologies for growing non-traditional objects in order to increase the economic performance of Ukrainian fish farming, and their comprehensive analysis will allow us to develop the main elements of the technology for growing tench in intensive aquaculture conditions.

Keywords: tench, stocking density, recirculation aquaculture system, weight, daily growth rate, specific growth rate, fish productivity, survival, feed costs.