BIOLOGICAL CHARACTERISTICS OF ROACH (RUTILUS RUTILUS L.) FROM THE GREAT BAY OF LAKE ONEGA USING METHODS OF MATHEMATICAL STATISTICS

Dzyubuk Irina Mikhailovna, Klyukina Elena Alexandrovna

The analysis of the results of studies of the biology of roach (Rutilus rutilus L.) from the Great Bay of Onega lake (Karelia) is presented in the article. Fishing was carried out in the summer period (June and July) 2023 near the coast of Kizhi Island and at a distance (500 m) from it. A total of 42 fish specimens were studied. It has been revealed that roaches aged from 2+ to 7+ years inhabited near the coast of Kizhi Island (individuals 3+ and 4+ years old predominated), in which the body length was in the rage of 10.8–19.6 cm, the mass of 9.1 g to 97.0 g and the fatness of 0.7 to 1.4. At a distance from the island, roaches aged 6+–10+ years fattened (individuals 8+ years old predominated), for which the length was in the range of 17.9–28.2 cm, the mass of 78 g to 165.3 g, the fatness of 0.8 to 2.4. It has been established that for the roach (R. rutilus L.) from the Great Bay, males (60%) predominated over females (40%) in percentage terms. The equation for the growth of roach (2+―10+ years) from the Great Bay of Onega lake was obtained ( , where W ― mass, g, Lt ― body length AC, cm). It has been revealed that the growth rate of roach from the Great Bay of Onega lake (Middle Karelia) is lower than that of roach from lakes Pryazhinskoye and Shangima (Lake Onega basin, South Karelia).

Keywords:roach, weight, body length, fatness, age composition, sex composition, Great Bay, Onega lake