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Vol. 29 (2026 year), No. 3, DOI: 10.21443/1560-9278-2026-29-3

Dolotov S. I., Potutkin A. G.
Distribution of mature burbot (Lotta lotta L.) in the Verkhnetulomsky reservoir (Murmansk region) in the post-spawning period

In March – April 2023, the burbot distribution was studied in one of the bays of the Verkhnetulomsky reservoir. It was found that mature fish aged 6+ to 11+ lived exclusively in a coastal strip 400 m wide, with a maximum depth of 11.8 m. Within this zone, the minimum abundance of fish was observed at depths up to 10.8 m, the maximum – between depths of 11.2 and 11.8 m. Burbot aged 6+ and 7+ were found along over the entire depth range, and those who have reached the age of 8, 9, 10 or more years – at depths of at least 9.2, 10.8 and 11.2 m, respectively. The proportion of females increased steadily from 25 % at depths up to 9.2 m to 70 % at depths of 11.2–11.8 m. The most likely reason for burbot habitat exclusively in the coastal strip of the reservoir was the location of a layer of water with low oxygen content at a depth of more than 11.8 m. The pronounced uneven distribution of burbot abundance within this zone was associated with the distribution of burbot individuals of different ages. The same factor, combined with the predominance of females in the older age groups, caused differences in the distribution of fish of different sexes. In turn, the uneven distribution of burbot of different ages was presumably related to differences in their temperature preferences, which are manifested in an increase in preferred temperature, which occurs as the age of the fish increases. Due to the lack of data, the verification of this hypothesis requires additional research. The practical aspect of the presented results is their use to refine estimates of commercial and spawning burbot stocks.

(in Russian, стр.10, fig. 5, tables. 0, ref 26, AdobePDF, AdobePDF 0 Kb)