Downstream migration of Burbot Larvae (Lota lota) in the section of the Irtysh River

Abstract

In this work, a study was made of the downstream migration of burbot larvae. To carry out the control catch, the larvae were trawled during the spring flood using a small motor boat. As a result of the work, it was found that the main factor affecting the number of larvae in the watercourse is the water temperature factor. Statistical analysis showed that more than 40% of the factors influencing the runoff of burbot larvae in the studied section of the river were taken into account. A mathematical model is proposed that reflects the dynamics of the number of larvae depending on the water temperature. It was shown that during the study period, with an increase in the level and temperature of the water, as well as the speed of the current, the number of larvae decreased from 0.7 to 0.005 ind./m3. The body length of the larva in the control catches ranged from 2.98 to 4.71 mm. Control fishing was carried out immediately after the river was opened from ice, the duration of the period during which migration continued was 10 days. Larvae were not recorded in trawl catches when the water temperature reached 6.53 ¼.