Linear Growth of Sparsely Rakered Whitefish Coregonus lavaretus (Coregonidae) of the Imandra Lake (Murmansk Oblast) / Zubova E. M., Kashulin N. A., Terent’ev P. M. [et al.] // Journal of Ichthyology. – 2016. - Vol. 56, №. 4. - P. 588–599

592 ZUBOVA et al. x102 20 16 12 8 4 0 20 16 12 8 4 (b) I — I________ 1 ____L_ 0 Fig. 2. Concentrations of heavy metals and aluminum in water of the Imandra Lakes in different years, ^g/L: (a) Babinskaya Imandra, (b) Yokostrovskaya Imandra, (c) Bolshaya Imandra; (■) 1983—1992 (according to Antropo- gennye modifikatsii..., 2002), (■) 2011—2013. Fig. 3. Concentrations of heavy metals in the surface layer (0—1 cm) of bottom sediments in the Imandra Lakes in different years, ^g/g dry weight: (a) Babinskaya Imandra, (b) Yokostrovskaya Imandra, (c) Bolshaya Imandra; see the designations in Fig. 2. The share of the whitefish individuals that prepared for spawning (the third-fourth stages of gonad devel­ opment) was approximately 19% in the Babinskaya Imandra, 17% in the Yokostrovskaya Imandra, and only 9% in the Bolshaya Imandra. According to the data of Reshetnikov and Bodganov (2011), this indica­ tor is much higher (50—60%) for natural, unpolluted ponds. In the Babinskaya Imandra, the age of first- spawning males (4+) and females (5+) corresponded to the natural one; in the Yokostrovskaya Imandra, both males and females matured earlier at the age of 3+ and, on a massive scale, at the age of 4+. The catches of the Bolshaya Imandra contained only three individuals with gonads at the third to fourth stages: two males (4+ and 7+) and a female (6+). With con­ sideration of the irregular entry in a spawning popula­ tion, the irregularity of spawning, and total lifetime of whitefish at the Imandra Lakes, most of individuals may take part in spawning only once in lifetime. Most of first-spawning whitefish individuals of the Imandra Lakes in our catches reached the linear sizes typical for sparsely rakered whitefish from clean ponds: 27—30 cm for males and 28—30 cm for females (Reshetnikov and Bogdanov, 2011). The samples from the Bolshaya, Yokostrovskaya, and Babinskaya Iman­ dra lakes were represented by individuals with a FL of 212—374 (310.7 ± 6.3) mm and weight of 109—940 (437.7 ± 30.3) g, 113-464 (273.9 ± 2.1) mm and 15­ 1660 (261.9 ± 7.5) g, 150-436 (266.3 ± 4.8) mm and 29-1350 (249.3 ± 16.2) g, respectively. The average values of length and weight in the whitefish of the Yokostrovskaya Imandra are higher (p < 0.001) than in the Babinskaya Imandra up to the age of 4+ (Table 4). In the Bolshaya Imandra, the size and weight parameters of individuals are larger (p < 0.001) up to the age of 5+ in comparison with the other lakes. From the age of 6+, the size and weight parameters of the whitefish in the different Imandra Lakes do not significantly vary. Therefore, different conditions in the three Iman­ dra Lakes are connected with the reliable distinctions in the size and weight parameters and age of the begin- JOURNAL OF ICHTHYOLOGY Vol. 56 No. 4 2016