Research of spawning grounds sterlet Acipenser ruthenus in rivers of Novosibirsk, Tomsk and Omsk regions

Abstract

Data on potential spawning grounds of the sterlet Acipenser ruthenus in the south of Western Siberia, in the Ob and Irtysh rivers (within Novosibirsk, Tomsk, and Omsk regions) are presented. There are 12 sites potentially suitable for natural reproduction of sterlet over a considerable length of the Ob, from 708 to 1135 km according to the Pilotage Map (PM). On 5 of them (in the area of the village Pochta, 761–759 km of the PM; Uspenka 782 km of the PM; Kireevsk 913.5–924 km of the PM; Oskino 937.5–950 km of the PM; the mouth of the Tom River 985–998 km PM) sterlet spawning was noted by the presence of early juveniles and (or) the presence of spawning growers. The total area of sites suitable for the natural reproduction of sterlet was 32.11 km². There are 14 sites potentially suitable for natural reproduction of sterlet over a considerable length of the Irtysh, from 2026 to 1310 km according to the PM. Their total area is 2.39 km². Identified areas in the Ob and Irtysh is characterized mainly by pebble soils (less often — sandy-pebble or rocky) and significant depths, from 3 to 16 m at the time of the survey. Thus, in the Ob and Irtysh despite hydroconstruction, extraction of sand-gravel mixture and other anthropogenic impact on the habitat, the conditions for the natural reproduction of sterlet have been preserved. The data obtained will serve as the basis for developing plans for the protection of sterlet in the region and making proposals for changes to the Fishing Rules for the West Siberian.