Ichthyofauna of Danube delta lakes

aspects of fish communities from Danube delta lakes are related in this work paper. The ichthyofauna from complexes lakes of Danube Delta was studied in 3 years (2003-2005), using twocomplementary methods of sampling: electric fishing and gillnet fishing. The species richness included 34 fish species (1/2 from total are commercial species) in Danube delta lakes: 20 fish species in Somova-Parches complex lakes, 24 species in Sontea-Furtuna, also 24 species in Matita-Merhei, 27 species in Gorgova-Uzlina and 29 species in Rosu-Puiu. Regard to richness fish species we can see that the fish richness increase from top Danube delta to theBlack Sea area. For both methods of fish sampling and in all Danube delta studied lakes, the most abundant species is Alburnus alburnus, following by Rutilus rutilus, Carassius gibelio, Scardinius erythrophthalmus, Rhodeus amarus, Blicca bjoerkna and Perca fluviatilis some of these species having small size in total length. Rare species are Hypophthalmichthyes molitrix, Acipenser stellatus, Vimba vimba and Atherina boyeri. Ecological significance (W):leading species is A. alburnus, follow by characteristic species R. rutilus and accompanying species S. erythrophthalmus, R. amarus and C. gibelio. Majority of fish species are included in associated and accessory species categories and some species are accidentally in Danube delta lakes, like: A. stellatus, V. vimba, H. molitrix and A.boyeri. For whole Danube delta Shannon-Wiener indices are more than1.5 and Evenness indices are more than 0.5 indicated a medium stable unto stable ecosystem, with differences between both sampling methods.