Sandimirov S.S. Catalogue of lakes in the Russian, Finnish and Norwegian Border Area. Finland, Jyvaskyla: Kopijyva Oy, 2008.

-200 200 600 1000 1400 1800 Weight, g 21 % 14% 7% 0% : 15 10 5 10 15 20 25 30 35 40 45 50 Length, cm 70% 50 56% 40 42% 1 ................ 30 > 3 о 28% I P 20 - 14% / ' ‘ 10 0% У i.M . . . 0 0+ 1+ 2+ 3+ 4+ 5+ 6+ 7+ Age, yrs Fig. 66. Age distribution of the sparsely rakered white- fish in Lake Kantojarvi. The size of pike varies over a wide range: weight from 175 to 2535 g, and length from 31.2 to 70.0 cm. The mean values are 1010 g and 48.4 cm, respectively. The age limit of the pike is 8 years, but 2-year old specimens are predominant and fish older than 6 years are caught only occasionally. In the sex distribution, males predominate over females (1.5:1).The perch in the lake are small sized.The maximum weight and length do not exceed 194 g and 23.7 cm, with average values of 90 g and 18.2 cm, respectively. There is no dominating group in the size and weight distribution, which indicates ir­ regular population recruitment. The age of the largest perch individuals do not exceed 4 years, and 3-year old fish are predominant. The sex distribution is characterized by a male to female ratio of about 1. Fish p a th o lo g y The frequency of occurrence of pathologies of the liver of whitefish (pale liver and mosaic structure) is 54%. The development of connective tissue expansions in kidneys occurs in 29% of the fish. Changes in the reproductive system and gills are character­ istic of 13% and 11% of the fish, respectively. H eavy m eta ls in £sh The heavy metal concnetrations (Cu, Ni, Pb and Cd) in fish muscle do not exceed the standard values. However, Hg concentrations in pike muscle exceed the maximum per­ missible concentration (Table 43). Metal concentrations (pg/g of wet weight) in liver, kidneys and gills are higher than in muscles, apart from Hg. The Cu concentrations in the liver ofwhitefish and pike are more than 20 pg/g, and the Ni concentrations in kidneys from 2.3 (pike) to 1.5 (whitefish) pg/g. Perch has higher accumulation of Ni (kidneys) and Cu (liver). The Cu concentrations in the liver of pike and whitefish are at least 3 times higher than those in perch liver. The Hg concentrations in pike muscle are higher than those in other fish species (Fig. 67). Fig. 65. Size and weight distribution of the sparsely rakered whitefish in Lake Kantojarvi. Catalogue of Lakes in the Russian, Finnish and Norwegian BorderArea 119