Exterior and weight characteristics of age-1+ brown trout (Salmo trutta Linnaeus, 1758), rainbow trout (Oncorhynchus mykiss Walbaum, 1792) and brook trout (Salvelinus fontinalis Mitchill, 1814)

Purpose. To study and analyze the results of the phenotypic parameters and the rate of linear and weight growth of 1+ salmonids (Salmo trutta m. fario, Oncorhynchus mykiss, Salvelinus fontinalis) grown in the tanks of the farm "Fish Stream" in the Transcarpathian region. Methodology. Material for the study were 1+ brown trout, rainbow trout and brook trout served. Morphometric measurements of fish were carried out according to generally accepted techniques for salmonids. Weighing of fish was conducted on electronic analytical scales. Processing of the obtained data was performed in Microsoft Office Excel (2007). The analysis of variables was performed in the system of absolute values. The criteria for the analysis of parameters were their mean value and standard error (M ± m). Findings. Based on the obtained results, a comparative analysis of morphometric measurements, exterior indices and growth rates of the investigated fish species was conducted. It was found that the highest condition factor was in brook trout - 1.52, somewhat lower it was in rainbow trout and the lowest in brown trout - 1.33 and 1.26, respectively. The big head index was the lowest in brown and rainbow trout - 21.2 and 21.42, respectively. The body height index of rainbow trout and brook trout was almost the same and quite low, indicating on their stockiness. When performing a detailed study of weight accumulation and average daily gain, it was found out that at age-1+, the highest final weight was in brook trout – 288.56 g, which is 10.01% and 118.5% more relative to rainbow trout and brown trout. On average, from April to September, the average daily gain in brook trout, rainbow trout and brown trout was 1.48 g, 1.37 and 0.67 g, respectively. Originality. For the first time in Western Ukraine, a study of morphometric parameters and growth rates of age-1+ fish of valuable species of trout farming was conducted. Practical Value. In the process of salmonid rearing with continuous study of their weights, morphometric, morphological and physiological features, the obtained results can be used to improve fish-technological and breeding work in the direction of increasing meat production and improving the production efficiency of certain salmonid species.