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

LINEAR GROWTH OF SPARSELY RAKERED WHITEFISH 597 200 J 100 J-4 ОЙ з 5 0 ---------------1---------------1---------------1---------------1 0 2 4 6 8 Zooplankton biomass, g/m3 Fig. 6. Dependence of the absolute linear growth in the sparsely rakered whitefish Coregonus lavaretus in the first year of life on the zooplankton biomass at the Imandra Lakes: y = 5.34x + 118.86, R2 = 0.93. 2 years. This leads to the whitefish of the Yokostro- vskaya and Bolshaya Imandra Lake entering the spawning population at the age of 3+ to 4+ vs. the age of 4+ to 5+ at the Babinskya Imandra. The length of the first-spawning whitefish in all the Imandra Lakes corresponds to the length observed in unpolluted ponds: 27—30 cm (Reshetnikov, 1998; Reshetnikov and Bogdanov, 2011). Therefore, the study of intra­ population whitefish groups from the different Iman­ dra Lakes shows that the higher is the growth rate in the fish (in our case, in the first year of life), the earlier is the age of their maturity. The described regularity is one of the forms of the relationship between the rates of growth and sexual development, which was noted in different fish species in natural conditions (Zamakhaev, 1964; Zemskaya, 1964; Koshelev, 1971; Nikol’skii, 1974; Reshetnikov, 1980; Trudel et al., 2000). A high negative correlation is observed between the average length in the whitefish from the different Imandra Lakes at a certain age and both the absolute and relative increase in the next year: the larger is the length, the smaller is the linear increase (Fig. 7; Table 5). This results in the equalization of length in the white- fish from the three Imandra Lakes at the age of 5 years. After the age of 5 years, we see the divergence of the length in the whitefish from the three lakes again, which leads to the largest final size of the Babinskaya Imandra whitefish and the least size of the Bolshaya Imandra whitefish, and the final size of the Yokostro­ vskaya Imandra whitefish has an intermediate value. As a rule, the fish that reach sexual maturity earlier slow down their growth and usually have a smaller final size that the fish that mature late (Dgebuadze, 2001), which is confirmed by our data. As is known, the long impact of sublethal doses of heavy metals results in additional energy expenses for life and survival of fish under the conditions of pollu- 300 Fig. 7. Dependence of the absolute (a) annual and (b) rel­ ative increases on the calculated length in different years of life in the sparsely rakered whitefish Coregonus lavaretus in the Imandra Lakes: ( ) second year ((a) у = 0.004x + 46.11, R2 = 0.004, (b) у = -0.002.x + 0.56, R2 = 0.98), (■) third year ((a) у = -0.23x + 80.90, R2 = 0.98, (b) у = —0.002x + 0.56, R2= 0.99), ( ) fourth year ((a) у = -0.43x + 127.62, R2= 0.99, (b) у = -0.003x + 0.69, R2= 1), (•) fifth year ((a) у = -0.63x + 183.75, R2 = 1, (b) у = -0.003x + 0.89, R2 = 0.99). tion (Kashulin, 1994; Kashulin et al., 1999; Moi- seenko and Lukin, 1999; Moiseenko, 2000, 2002; Antropogennye modifikatsii ..., 2002). Under the condi­ tions of pollution, pathologies and dysfunctions develop with aging, which leads to the early death of fish. This can explain the reduction of the lifetime in the Bolshaya Imandra whitefish to 7+ instead of 12+ to 13+. The same number of age groups is also observed in the whitefish at the conventionally back­ ground Babinskaya Imandra Lake, which may be due to the high content of some heavy metals in water and bottom sediments of this Imandra Lake. ACKNOWLEDGMENTS We thank the staff of the aquatic ecosystems labo­ ratory of the Institute of the Industrial Ecology Prob­ lems of the North of the Kola Scientific Center of the Russian Academy of Sciences for assistance in the field works and consultations in the preparation of the article. Special thanks are expressed to M.V. Mina (Institute of Development Biology of the Russian Academy of Sciences) for valuable comments made during the discussion o f the study results. 60 a aey Ab 40 aercn 20 (а) 0.4 & e о ic repсл £ с Ѵнg 0.3 0.2 0.1 (b) 50 100 150 200 250 Calculated length, mm 0 JOURNAL OF ICHTHYOLOGY Vol. 56 No. 4 2016