Zooindication and ecological conditions of the Vistynetskoe lake

Abstract

The Vistynetskoe Lake has glacial origin and it is located in the south-eastern part of the
Kaliningrad region. According to its natural status, the lake belongs to oligotrophic type of
reservoirs with mesotrophic features.
The total surface area of the lake is 16. 7 km 2, with an average depth of 15.5 m, and maximum
length and maximum width 8.1 km and 4.2 km respectively. The latest researches in this are
were carried out in summer 2006. The water quality was estimated pursuant to the Pantle and
Bukk's method as modified by Sladechek, and Zooplankton, zoobentos and macrophyte
organisms were used as bioindicators for ecological conditions of the lake.
By that period, I 15 species of zooplankton were found, among them diaptomus Heterocope
appendiculata.
Similar species of zooplankton dominate by number of species, by their biomass and their
number is 3-4.
143 species of zooplankton were found in the Vistynetskoe Lake during the whole research
period.
Total area of the macrophyte overgrowth is less than 17% of the lake surface. Bushes have
qualitative and quantitative differences in length and depth distribution. By the overgrowth
the Vistynetskoe lake is similar to other bigger lakes in southern part of Lithuania.
The Chara, Pondweed, Elodea dominate among the submerged vegetation.
The saprobity index calculated for zoobentos and zooplankton does not exceed 1.6 . It
corresponds to oligo-P-mesosaprobic class of water quality. But there are some points where
the level of saprobity changes to polysaprobic.
Thus, by the level of zooplankton and zoobentos development the Vistynetskoe lake is closer
to mesotrophic type of reservoirs.