The probable reason for the high growth rate of grayling in the study area is that the fish do not have to waste energy on seasonal migration to the tributaries. Thus, despite the increased duration of the period with optimal water temperatures downstream of the dam of the Krasnoyarsk Hydroelectric Plant, fish growth was observed in a limited period of the year, from July to November. In November, there was no statistically significant difference between the circulus number in scale increment and the circulus number in the corresponding completed annuli of older fish. The calculation showed that a new annual ring was produced in July. The age of the fish is then determined by counting the number of annuli. The von Bertalanffy growth function was used to describe the increment in the number of circuli over a year. The circuli tend to be more widely spaced during the summers growth and more. (9) A Carpentier's ring was used in patient 1 and a polytetrafluoroethylene tube was used in patient 2 to reduce the diameter of the common atrioventricular annuli. The number of circuli outside the last identified annuli and in the second, third, and fourth completed annuli was estimated on 569 fish caught during the annual cycle. (Figure 5A) showed easily distinguishable wide-spaced circuli during summer and tightly-spaced circuli during winter periods. It has been demonstrated that the extended sheath consists of annuli of six subunits, which are arranged in a helix of 3.57 annuli per one turn. 1293-1302 ISSN: 0378-1909 Subject: animal growth, biomass production, energy, fish, growth rings, migratory behavior, rivers, temperature Abstract: The seasonal formation of annual rings on the scales of Baikal grayling from the middle reaches of the Yenisei River has been studied to find out the reasons for the high growth rate of the grayling under altered temperature regime downstream of the dam of the Krasnoyarsk Hydroelectric Plant. Zotina Source: Environmental biology of fishes 2021 v.104 no.10 pp. Seasonal formation of annual rings on the scales of Baikal grayling inhabiting the middle reaches of the Yenisei River under altered temperature regime Author: Ivan V.
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