Age and growth of the pike-perch Sander lucioperca in the south of Western Siberia
Authors:   Novosibirsk Branch of Russian Federal Research Institute of Fisheries and Oceanography (", Interesova Elena A. ,   ZapSibNIRO",   ),   Tomsk State University, Suknev Dmitry L. ,   Novosibirsk Branch of Russian Federal Research Institute of Fisheries and Oceanography ("ZapSibNIRO"), Shatalin Vladislav A. ,   Novosibirsk Branch of Russian Federal Research Institute of Fisheries and Oceanography ("ZapSibNIRO"), Morozko Anastasia V. ,   Novosibirsk Branch of Russian Federal Research Institute of Fisheries and Oceanography ("ZapSibNIRO"), Kabiev Talgat A. ,   Novosibirsk Branch of Russian Federal Research Institute of Fisheries and Oceanography ("ZapSibNIRO"), Dorogin Mikhail A. ,   Novosibirsk Branch of Russian Federal Research Institute of Fisheries and Oceanography ("ZapSibNIRO"), Tsapenkov Andrey V. ,   Novosibirsk Branch of Russian Federal Research Institute of Fisheries and Oceanography ("ZapSibNIRO")
Published: October 2024

The age and growth of fish are the most important characteristics underlying the assessment of the state of fish stocks and the forecasting of future catches. The pike-perch Sander lucioperca (Linnaeus, 1758) is an alien fish species in Western Siberia. It was first introduced into the Ob basin in 1956. The introduction of this species into the Novosibirsk reservoir was carried out in 1959-1964, and into Lake Chany in 1964-1966. Currently, pike-perch is spread throughout the Ob basin and is an important fishery target. This study summarizes long-term data from the Novosibirsk branch of Russian Federal Research Institute of Fisheries and Oceanography ("VNIRO") about the growth of different-aged individuals of the pike-perch, collected during monitoring of aquatic biological resources in the Novosibirsk reservoir (54°20' N, 81°57'E) and Lake Chany (54°55'N, 77°31'E) over the last 10 years (2013-2022). These water bodies are of different types: the Novosibirsk reservoir was formed on the Ob River, the maximum depth reaches 25 m, the average depth is 8 m. The area of the reservoir is 1.07 thousand km^. Lake Chany is located in the Ob-Irtysh interfluve, drainless, filled due to the runoff of the Kargat and Chulym rivers, atmospheric precipitation and groundwater. The maximum depth is up to 8 m, average depth is 2 m. The area of the lake fluctuates greatly from year to year depending on the water level, in the long-term aspect it has tends to decrease, currently amounting to about 2 thousand km. The lake water has increased mineralization in most of the reaches. Fish collection for analysis of size characteristics is carried out annually from commercial catches. The total volume of material for this study was 2953 individuals from Lake Chany and 1102 individuals from the Novosibirsk reservoir. As a result of this work, it was found that in commercial catches in different types of water bodies in the south of Western Siberia, pike-perch has been known at the age of up to 14+ years over the last 10 years. In Lake Chany, there were mostly individuals of age groups 2+-4+, and in the Novosibirsk Reservoir - 3+-6+ (See Fig. 1). The pike-perch size of the same age from commercial catches varies greatly from one year to the next in Lake Chany, and in the Novosibirsk reservoir (See Fig. 2). It confirms the data on significant variability in growth rates of this species and indicating the need for a cautious approach to comparing the length and weight of pike perch in different observation periods. On average, over the last decade, pike-perch in Lake Chany is characterized by a slightly shorter standard length and greater weight than in the Novosibirsk Reservoir, however, the differences reach statistical significance (p < 0.001) only when comparing fish aged 2+ by standard length (See Fig. 3). The analysis of the relationship between the growth rate of pike-perch and environmental temperature showed that the absolute increase per year of standard length and weight of younger age groups fish in the Novosibirsk Reservoir has a statistically significant positive correlation with the temperature in April (r = 0.6110.775), and in Lake Chany - in May (r = 0.633-0.737) (See Tables 1, 2). Considering that the average April temperature in the area of the Novosibirsk reservoir is 1.9°C higher than in the area of Lake Chany, probably, in the latter, juvenile pike-perch begins to actively feeding a little later. It may explain the smaller sizes of pike-perch of younger age groups in Lake Chany compared to the Novosibirsk reservoir. The article contains 4 Figures, 2 Tables and 28 References. The authors express their gratitude to all colleagues - employees of the Novosibirsk Branch of "VNIRO", who over in different years took part in collecting the material. The Authors declare no conflict of interest.