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

lies: trout ( Salmo trutta), arctic char ( Salvelinus alpinus), whitefish (C o regonu s lavare- tus), grayling ( Thymallus thymallus), pike ( Esox lucius), minnow ( Phoxinus phox i- nus ) and nine-spine stickleback ( Pungitius pun gitiu s ). However the last two species were not found in our catches. Overall, whitefish predominates in Lake Mellalompolo. Grayling is also a common fish in this lake. Trout, arctic char and pike occur only oc­ casionally (Fig. 71). Sparsely rakered whitefish inhab­ its the lake (up to 30 gill rakers). The weight and length of the fish range from 7-888 g (average 329 g) and 9.3-40.5 cm (average 27.9 cm), respectively. There are two groups in the size and weight distri­ butions: specimens with a weight of up to 100 g and length of 15-20 cm, and fish with a weight 400-600 g and length of 30-35 cm (Fig. 72). whitefish 75.4 grayling 17.2 trout 3.0 char 3.0 pike 1.5 Fig. 71. Distribution offish spe­ cies in Lake Mellalom­ polo. 3 о С - Fig. 72. Size and weight distribu­ tion of the sparsely rakered whitefish in Lake Mellalompolo. 5 10 15 20 25 30 35 40 45 Length, cm The age limit of whitefish is 8 years. 2-year-old (33%) and 5- to 6-year-old (40%) fish are the most numerous (Fig. 73). Some whitefish individuals appear to have very high growth rates. This is most probably due to the escape of mature fish from the fish farms into the water bodies. The ratio between females and males is 1.1:1. The average size of the trout are weight 346 g and length 29.5 cm. The average weight of char is less than that of trout (293 g), but the length is 30.4 cm. The age limits of both species do not exceed 4 years. Some pikes at the age of 7 years have a weight over one kilogram (1205 g), and length up to 56.0 cm. The bulk of the grayling population consists of fish with a weight of 300-600 g and a length of 30-34 cm. The average weight is 261 g and 168.3 cm, respectively. There are no graylings older than 8 years. Females are predomi­ nant over males (1.4:1). Fish p a th o lo g y The initial stage of pathologies in white- fish organs and tissues have been ddocu- 30 25 15 І Fig. 73. 10 Age distribution of 5 the sparsely rakered whitefish in Lake 0 Mellalompolo. 0+ 1+ 2+ 3+ 4+ 5+ 6+ 7+ Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea 127