Ecologica Montenegrina 39: 30-45 (2021) This journal is available online at: www.biotaxa.org/em http://dx.doi.org/10.37828/em.2021.39.4 First researches of the underwater ecosystem communities of an underground channel built in 1950s (Balaklava bay, Sevastopol) NELLY G. SERGEEVA1*, YURIY S. TARARIEV2, ROMAN V. GORBUNOV1, NIKOLAY K. REVKOV1 , NATALYA A. BOLTACHOVA1, GENNADIY V. SAMOKHIN3, ALEXANDER M. SHCHERBICH1, MAKSIM P. KIRIN 1, OLGA A. MIRONYUK1, LYUDMILA F. LUKYANOVA1 & VITALIY A. TIMOFEEV1 1 A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Sevastopol, Russia 2 Military History Museum of Fortifications «Balaklava», Sevastopol, Russia 3 V.I. Vernadsky Crimean Federal University, Simferopol, Russia *E-mail:
[email protected] Received 24 November 2020 │ Accepted by V. Pešić: 11 January 2021 │ Published online 20 January 2021. Abstract The results of the first studies of the ecosystem state of the underwater part of the channel, artificially created in the middle of the 20th century on the western shore of the Balaklava Bay (Sevastopol) as a naval base of the Black Sea Fleet for the submarines repair, are presented. Channel's ecosystem is determined by uniqueness of anthropogenic formation and considered as analogue of natural Black Sea cave. Hydrospelological survey of the channel and biological studies allowed assessing its current state, the nature of biofouling of its walls and anthropogenic and technical pollution of the bottom. Macrofauna of the channel wall biofouling is represented by the Mytilaster lineatus community, which has a high level of species abundance (about 80 species have been registered) and quantitative development. Both in taxonomic diversity and in quantitative terms, this community is comparable to the rocky substrate community near open Crimean coasts, but with a smaller share of crustacean group development.