The taxonomic composition and quantitative characteristics of the macrozoobenthos of the largest lake in Ukraine Yalpug, were studied. In 2006-2012 some 396 samples of macrozoobenthos were collected on the littoral and sublittoral of Lake Yalpug. 183 species and subspecies of Spongia, Hydrozoa, Turbellaria, Annelida, Crustacea, Insecta, Gastropoda, and Bivalvia were found. All the species were found on the littoral, while in the sublittoral -only 47 species. For the first time, we discoeverd 46 species for the lake zoobenthic fauna. Ponto-Caspian faunal complex was represented by 19 species. The littoral species number had changed from 63 species in the upper reaches to 160 in the lower reaches of the lake. In littoral habitat the number and biomass increased from winter to summer, and in the sublittoral habitat the abundance increased from winter to summer, whereas the biomass -from winter to autumn. The most abundant were oligochaetes and chironomids, the maximum biomass was registered for molluscs. During the growing season, the average abundance and biomass of macrozoobenthos in the littoral area were 2482 ind./m² and 117.0 g/m² respectively; in sublittoral area -1600 ind./m² and 121.0 g/m² respectively.

The macrozoobenthos of Cahul Lake (one of the largest in Ukrainian Danube basin) has been studied. We collected 256 samples at 12 littoral and sublittoral stations within [2006][2007][2008][2009][2010][2011][2012]. Some 95 species and subspecies were found, namely: Spongia -1 species, Turbellaria -2, Annelida -17, Bryozoa -1, Crustacea -19, Insecta -35, Gastropoda -15 and Bivalvia -5 species, among them 15 previously unregistered species were found. We discovered that the overall number of species increased downstream. Seasonal dynamics of species composition is poorly expressed. The maximum number of macrozoobenthos on the littoral was recorded in spring, maximal biomass -in summer; Maximum sublittoral abundance and biomass of macrozoobenthos were recorded in the summer. Key words: Lake Cahul, macrozoobenthos, taxonomic and quantitative characteristics

<p><span lang="EN-US">The taxonomic composition and quantitative characteristics of macrozoobenthos of the Danube Lake Kugurlui have been studied. In 2006-2012 on the littoral and sublittoral of the lake, 278 macrozoobenthos samples were collected. There are 172 species of Spongia, Hydrozoa, Turbellaria, Annelida, Crustacea, Insecta, Acarina, Gastropoda, Bivalvia. All species are found on the littoral, in the sublittoral - 48 species. There are 36 species new to the lake. Ponto-Caspian faunal complex is represented by 19 species. The number of species on the littoral decreased from 129 in the upper reaches to 98 in the lower reaches, in the sublittoral was within 35-37 species. On the littoral, the abundance and biomass of macrozoobenthos increased on average throughout the lake from winter to summer, in the sublittoral biomass increased from winter to autumn, the maximum number was recorded in the spring. The number was dominated by oligochaetes and chironomids, and by mollusks by biomass.</span></p>