Biomorphological Indicators of Rainbow Trout (Oncorhynchus mykiss) Fry: Comparative Analysis in the Conditions of the Lower Kolsay and Fish Farms

Rainbow trout (Oncorhynchus mykiss Walbaum, 1792) is one of the key species in aquaculture of the salmon family due to its high commercial value and the availability of farming technology. This paper presents data on the morphometric characteristics of rainbow trout fry grown in three types of farms in Kazakhstan and wild forms from Lake Lower Kolsay. The comparison was performed using geometric morphometric analysis based on 9 numerical and 28 plastic traits. Differences were assessed using the Mann-Whitney criterion and principal component analysis (PCA). The influence of factors such as hydrochemical conditions, spatial constraints and stocking density was established. The results are important for assessing the risk of bio-contamination and preserving the gene pool when stocking fish in the developing aquaculture of Kazakhstan. The novelty of the study is dictated by the need to form a comprehensive database on morphology, monitoring studies of trout farms for the purpose of further developing measures to control the level of selection stability and additional measures to reduce the risk of spreading low-viability and genetically depleted fish among fish farming entities in Kazakhstan.