Analysis of Linear-Weight Indicators and Meristic Characters of the Siberian Sterlet Acipenser Ruthenus Marsiglii (Brandt, 1833) in the Irtish River Basin

Abstract

In the basin of the Irtysh River, one of the mass representatives of the Acipenseridae family is the Siberian sterlet Acipenser ruthenus marsiglii (Brandt, 1833). Today, the catch of sterlet in this region is allowed only as control catches for scientific research. Poaching causes a great loss for the species. In the period from 2013-2016 there were held 44 forensic and ichthyologic examinations, including 26 criminal case examinations and 18 expert examinations on the materials of the Register of Complaints concerning Offences. 665 species of Siberian sterlet were caught illegally. In these illegal catches, species with a body length of 31.0 to 40.9 cm were most often found (this made 55.2% of all years of expert examinations), species of 21.0-30.9 cm length made 26.3%, of 41.0 to 50.9 cm length made 16.4%. When analyzing the total mass of fish caught illegally from 2013 to 2016, it was found that species having a mass 100.0-199.9 g were most often found, their share of the total number of fish was 51.6%. Species with a mass 200.0 - 299.9 g made 17.1%; with a mass 0-99.9 g - 15.6%. In this study, the minimum number of lateral beetles in sterlet was 49; maximum - 69; dorsal beetles 11-18; the number of gill rakers corresponded to the specific number and varied from 17 to 29 (mean 14). The meristic features of the species under study correspond to the subspecies Siberian sterlet Acipenser ruthenus marsiglii (Brandt, 1833).

Characteristics of the ecological danger of illegal poaching fish catches in the lower reaches of the Irtysh river

“…Representatives of the sturgeon (Acipenseridae), burbot (Lotidae), carp (Cyprinidae), perch (Percidae), whitefish (Coregonidae), and pike (Esocidae) families form the basis of the ichthyofauna of the Lower Irtysh River [4]. The same representatives are objects of illegal fishing [5][6][7][8][9]. The sturgeon family is represented by Siberian sturgeon (Acipenser baerii Brand, 1869) and sterlet (Acipenser ruthenus Linnaeus, 1758).…”

The parasitofauna of the Siberian sterlet Acipenser ruthenus marsiglii of the Lower Irtysh

“…Sterlet quite like warm water, winter in river pockets, and are typical benhtophages -the basis of their food is chironomid larvae, Simuliidae, mayflies, dragonflies, molluscs, and other representatives of macrozoobenthos (Strel'nikova, 2012). Because of the high industrial value of sterlet, and therefore their intensive fishing, and also change in hydrological and hydrochemical regimes of water bodies (places of spawning and fattening), by the end of the 1970s, the reserves of sterlet in the Ob-Irtysh basin had become critical (Liberman, 2017). Currently, there is no industrial fishing of sterlet in this basin, catching takes place only for scientific purposes.…”