NEW DATA ABOUT ZOO-BENTHAL POPULATIONS OF ROMANIAN LITTORAL LAKES

摘要

On the basis of 58 bottom samples collected in the summer of 2000 the authors present the quantitative state of benthic associations in the lakes belonging to the Romanian littoral (from the south part -Neptun - to the north part: Siutghiol, Tasaul, Nuntasi and Babadag). In the all investigated lakes, the diversity of bottom fauna is relatively low -about 32 taxa, 17 species and 15 supra-specific taxa were identified (in all lakes 6 taxa and 5 supra-specific taxa are commune). Among the benthic invertebrates, the crustacean and insect-larvae populations are the most important, by their numerical density; they are followed by Nematoda and Oligochaeta from worm group and mollusca populations. Generally, the largest part of the bottom fauna occurs on all type of substratum in the all lakes, being eurytop species (nematod and oligochata worms, same species of ostracoda and copepoda crustacean). Some species are peculiar only for certain type of substratum, being less numerous (turbellarian and hirudinea species worms, some species of mysidaceam crustacean: Paramysis baerii bispinosa on the sandy bottoms, Pterocuma pectinata - cumaceam crustacean and Gammaridae amphipoda on the submerged vegetation). Between benthic populations from all lakes analysed, some of the relict Ponto-Caspian fauna (species of Theodoxus, Gammaridae species, Paramysis, Pterocuma) is more abundant in the lakes from the north part of the Romanian littoral.