Description of the European River Lamprey Lampetra fluviatilis (L., 1758) from the Lososinka River(Onega Lake Basin)

摘要

Representatives of the species European river lamprey Lampetra fluviatilis (Linnaeus, 1758) significantly differ in their morphological characters and produce forms with different life strategies [1]whose relationships are unclear. Parasitic representatives of this species (L. fluviatilis sensu stricto) migrating from rivers to lakes and seas for feeding and returning back to the rivers for spawning are of special interest. They are recorded in the IUCN Red Data Book (protection status LC) as speciesthat are still rare in some parts of their ranges but the state of whose populations has been considerably improved |2|. Recently, in Russia and Baltic states, the fishery for lamprey has been resumed. The lampreys feeding in lakes Ladoga and Onega havenot been investigated yet. There is only a study 131 whose author identified the lamprey living in Lake Ladoga as L. fluviatiis forma ladogensis, providing no diagnostic characters differing the Ladoga form from the typical migratory lamprey (forma typica), except for the total body length.There is no information on the morphology of lamprey living in Lake Onega, connected with Lake Ladoga by the Svir River. Berg |4|, having compared morphological characters of large migratory lampreys (forma typica) and small lacustrine parasitic lampreycaught in lakes Ladoga and Onega, assumed the latter to be the rapidly maturing form, forma praecox. In spite of publication of this book by Berg |4| in 1948, it contains data of the 1930s, i.e., those collected before the construction of the first dam on the Svir River (1936), which has become an insurmountable barrier for the anadromous spawners.