Morphological features of round whitefish Prosopium cylindraceum lake Lama (Putorana Plateau)

Abstract

The article presents materials on the meristic and plastic characteristics of the round whitefish, Prosopium cylindraceum (Pennant, 1784), in Lake Lama, which is part of the Norilo-Pyasinsky water ecosystem and the Pyasina River basin. The Yenisei and Pyasina rivers define the western boundary of this species’ habitat. While the round whitefish is a relatively rare species with a low population in the Yenisei basin, it is abundant in the Pyasina basin, especially in some of the upper water bodies. The round whitefish is a common species in the Norilo-Pyasinsky lakes and is present in all large lakes of the region, except for lake Keta, where it has not been found. Both river and lake-river forms of the round whitefish are present in these water bodies. Both forms have experienced a significant impact from non-commercial fishing, and in some parts of the basin, they have practically disappeared or significantly reduced in number. The areal of the round whitefish in the Pyasina River basin also extends to some right-hand tributaries (Dudypta, Samoyedskaya, etc.) in the northern regions of the basin. The tributaries where the round whitefish is found are typically characterized as rocky, fastflowing streams. The variability of meristic characters of the round whitefish in lake Lama, lake Sobachye, and some parts of the upper Pyasina river are examined. Current data show the round whitefish in the Pyasina River basin and other water bodies of the Taimyr region is represented by a relatively homogeneous population with close values in such basic parameters as lateral line, the number of gill rakers, and other characteristics.