Alien invasive fish species of Republic Karelia

Study Extent

Waterbodies in borders of the Republic of Karelia, in the volume of samples during the study period.

Sampling

Collecting on different lakes and rivers and visual observations.

Method steps

1. Collecting or observing specimens, identification of collected specimens, digitizing the data with MS Access and MS Excel, carrying out statistical analysis of data set.

All fishes were identified to species level.

1. Oncorhynchus gorbusсha
   rank: species
2. Oncorhynchus mykiss
   rank: species

Republic of Karelia The tracked fish species (pink salmon) is detected in rivers in borders of the Republic of Karelia, located in north (riv. Keret (66.28166 / 33.58333); riv. Suma 64.29472 / 35.40944; riv. Kem 64.95527 / 34.67444). The pink salmon is a commercial specie. Pink salmon has the shortest life cycle in the Salmonidae family. It becomes sexually mature on the second year of life. It grows rapidly, reaching a length of 32-64 cm and a mass of 1.4-2.3 kg. Pink salmon spawns from July to September. As a rule, it does not migrate far upstream and prefers spawning in lower river stretches. Its fecundity varies from 800 to 2400 eggs. After spawning all the fish die. Larvae hatch from late September to January. The downstream migration of larvae into the sea begins in mid-May at a temperature of 3-4°С and continues until late June. An instinct of returning to the home river (homing) displayed by pink salmon is more poorly developed than in other species of the genus. Therefore, it goes occasionally to “alien” rivers. Pink salmon appeared in Kola Peninsula rivers as a result of 1950-1960s purpose-oriented introduction. In the White Sea basin pink salmon has spread into all large and medium-sized salmon spawning rivers with a mean annual water discharge of more than 25 m3/s; sometimes it goes for spawning to small rivers with a mean annual water discharge of 7 m3/s.