Fish helminths in reservoirs of the Zarafshan river

The results of the study of the helminth fauna of 8 species fish of the lower reaches reservoirs of the Zarafshan River are presented - carp (Cyprinus carpio), crucian carp (Carassius auratus gibelio), roach (Rutilus rutilus), oriental bream (Abramis brama), pike perch (Stizostedion lucioperca), silver carp (Hypophthalmichthys molitrix), pike (Esox lucius), Turkestan barbel (Barbus capito conocephalus). 27 species of helminths were identified, including 12 species of cestodes (Caryophyllaeus laticeps Pallas, 1781; Caryophyllaeus fimbriceps Annenkova - Chlopina, 1919; Biacetabulum appendiculatum Szidat, 1937; Khawia sinensis Hsu, 1935; Bathybothrium rectangulum Bloch, 1782; Bothriocephalus opsariichthydis Yamaguti, 1934; Ligula intestinalis Linnaeus, 1758 larvae; Digramma interupta Rudolphi, 1810 larvae; Proteocephalus torulosus Batsch, 1786; Neogryporhynchus cheilanoristrotus Wedl, 1855 larvae; Gryporhynchus pusillus von Nordman, 1832 larvae; Valipora campylancristrota Rudolphi, 1819 larvae), 5 species of trematodes (Sanguinicola inermis Plehn, 1905; Orientocreadium siluri Bychowsky et Dubinina, 1954; Allocreadium isoporum Looss, 1894; Diplostomum spathaceum Rudolvae, 1832 lare; (Dioctophyme renale Goeze, 1782 larvae; Rhabdochona denudata Dujardin, 1845; Desmidocercella numidica Seurat, 1920 larvae; Camallanus truncatus Rudolphi, 1814; Camallanus lacustris Zoega, 1776; Philometra ovatachenko Zeder, 1803; 1779 larvae) and 2 species of acanthocephalus (Pomphorhynchus laevis Muller, 1776; Acantocephalus lucii Muller, 1776). This work includes the results of the research of the helminthes of the fish of waterbodies in the lowers of the Zarafshan River. As a result, the infection of fish with 27 species of helminthes, belonging to cestodes (12), trematodes (5), nematodes (8), and acanthocephalans (2) was established.

Ratio of linear and weight growth of Sander lucioperca in the Novosibirsk water-storage basin

This research is devoted to the variability of linear and weight growth of Sander lucioperca (Stizostedion lucioperca) in the Novosibirsk water-storage basin. The presented work is part of a comprehensive research of Sander lucioperca phenotypic pool of the Novosibirsk water-storage basin. 43 individuals have been selected for the analysis aged 3,0–4,5 years in the period October-November 2019. Measurements of Sander lucioperca have been carried out according to the “Manual for the study of fi sh”, the fi sh has been weighed on a technical scale VLKT-500 with an accuracy of 1 g. The fi rst time the linear and some aspects of the weight growth of Sander lucioperca in the Novosibirsk water-storage basin have been described in the paper, since the growth directly depends on the development and is one of its components. The biological characteristics and features of Sander lucioperca have been analyzed. For the development of the population of Sander lucioperca as well as other fi sh species one of the main biotic factors is the feed supply. The availability of feed for hydrobionts is determined by the quantity, quality and availability of feed in the reservoir, since the feed supply has a signifi cant impact on the biological parameters of fi sh. The ecological situation of the Novosibirsk water-storage basin has been studied. The obtained data on Sander lucioperca measurements can be used as average population values. Increasing the parameters of the assessment of living organisms makes it possible to more accurately assess the conformation of animals. A high level of correlation (r=0,878) between the linear and weight growth of Sander lucioperca has been established, and a regression equation describing the change in length as a function of live weight (y = 9,5853 x + 39,1164) has been calculated. There is a tendency to decrease the number of Sander lucioperca in the Novosibirsk water-storage basin.

DEVELOPMENT OF MAJOR ORGAN SYSTEMS IN PIKE PERCH STIZOSTEDION LUCIOPERCA (PERCIFORMES: PERCIDAE) IN EARLY ONTOGENESIS

The article describes the features of developing major organ systems in pre-larvae and larvae of pikeperch at different stages. In the period of transition to exogenous feeding the nervous, musculoskeletal and digestive systems in pre-larvae body were the most developed. At the same time, cardiovascular, respiratory, excretory systems developed slower. In the beginning of active feeding the digestive, nervous and musculoskeletal systems in pike perch larvae were completely developed: there emerged taste buds, teeth in the oral cavity, were formed cartilaginous tissues, particularly at the skull base. In the cardiovascular system of larvae there continued process of differentiating the heart valves. The research results showed uneven development of main organ systems in pike perch pre-larvae and larvae, which is connected to the development of swim bladder and digestive system during transition to active feeding.