Morphological Features of the Vendace (Coregonus albula) Population from Lake Pleshcheyevo at the Beginning of the 21st Century

Abstract—This article analyzes the morphological and ecological features of the Pereslavl vendace (an endemic population of Coregonus albula that inhabits Lake Pleshcheyevo). The features of the size–growth and sexual structures, fecundity, and growth rate of the population for 2013–2017 have been studied. It is shown that the main trends for the current population of vendace from this lake are a decrease in the fish size and growth rate and fecundity. We believe that these changes result from the removal of fishing pressure on this population at the end of the 20th century, which has led to an increase in its abundance. The decrease in the growth rate and linear size of vendace from Lake Pleshcheyevo is due to increased intraspecific competition, in particular, during summer bottom hypoxia. This paper also discusses the results of a comparison of the morphological parameters of two sympatric phylogenetic lineages of vendace from Lake Pleshcheyevo (E and ALBP2) that currently cohabit the lake, but differ in origin. It is important that, despite a high genetic differentiation and different origins of these lineages, the morphological diversification of their representatives is very small and all the specimens belong to the same species, Coregonus albula.