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 591 Table 2. Average hydrochemical and hydrobiological parameters of three Imandra Lakes, 2011-2013 Parameter Babinskaya Imandra Yokostrovskaya Imandra Bolshaya Imandra Area, km2 148.7 352.2 311.6 Depth, m: maximal 43.5 42.0 67.0 average 16.3 10.9 14.7 Oxygen content, mg/L 7.39 8.98 9.37 pH 7.33 7.42 7.78 Total mineralization, mg/L 39.9 70.8 91.3 Total phosphorus, ^g/L 6 19 55 Total nitrogen, ^g/L 147 183 396 Metal concentration in water*, ^g/L/in the surface layer (0-1 cm) of bottom sediments, ^g/g dry weight: Cu (1, <3 )/(-, 36) 3.4/121 4.1/253 3.8/370 Ni (10, <2 )/(-, 33) 2.7/245 6.8/900 5.6/1860 Zn (10, <5 )/(-, 91) 0.9/115 0.2/93 0.5/131 Mn (5.6, - ) / ( - , - ) 2 .0 /- 29.2/- 18.5/- Sr (26, - ) / ( - , - ) 49.6/72 64.4/1747 108.1/3909 Pb (100, <0.5)/(-, 3.8) 0.1/25.0 0.3/15.6 <0.3/11.0 Co ( - , - ) / ( - , 14) -/24.0 -/23.4 -/43.1 Cd (5, <0.2)/(-, 0.8) 0.04/0.59 0.04/0.54 0.02/0.83 Hg ( - , - ) / ( - , 0.04) -/0.096 -/0.212 0.02/0.242 Al (30, - ) / ( - , - ) 23.3/24061 46.7/42294 224.7/52941 Phytoplankton biomass, g/m3 0.46 1.57 2.98 Content of chlorophyll “a”, mg/m3 1.41 3.68 6.12 Trophic status** a-oligotrophic a-mesotrophic p-mesotrophic Zooplankton abundance, spc/m3 265.5 880.2 1301.3 Zooplankton biomass, g/m3 0.5 2.6 6.9 Trophic status** Transitional from a - Transitional from a - Transitional from a - to р-oligotrophic type to р-mesotrophic type to р-eutrophic type Zoobenthos abundance, spc/m2 224 3900 7500 Zoobenthos biomass, g/m2 1.2 44.1 36.3 Trophic status** a-oligotrophic hyper-eutrophic p-eutrophic * In the brackets: the first value is the maximum permissible concentration and reference safe level of the impact of harmful substances for the water of fishery ponds; the second one is the background value in the water of 400 lakes in the eastern part of the Murmansk oblast (according to Kashulin et al., 2013). ** According to Kitaev, 1984. Imandra lakes is caused by the high trophicity of these lakes and high zooplankton biomass (Table 2) (Zubova and Kashulin, 2014). Making allowance for the small population size of densely rakered whitefish, this work presents the data only on sparsely rakered whitefish for the different Imandra Lakes. On the whole, the sparsely rakered whitefish was represented by ten age groups (from 0+ to 9+), but the age structure of catches in the different lakes varied: the catches in the Babinskya, Yokostrovskaya, and Bolshaya Imandra lakes was noted to contain individ­ uals aged 1+ to 7+, 0+ to 9+, and 2+ to 7+, respec­ tively. The whitefish aged 3+ to 5+ were prevalent in the Babinskaya and Yokostrovskaya Imandra, and those aged 4+ to 5+ were dominant in the Bolshaya Imandra. The fish over 5+ were approximately 19% of the sample in the Babinskaya and Bolshaya Imandra and 12% in the Yokostrovskaya Imandra. The white- fish over 7+ were few in the Yokostrovskaya Imandra (females). JOURNAL OF ICHTHYOLOGY Vol. 56 No. 4 2016