TY - JOUR AU - Anninsky, B. E. AU - Ignatyev, S. M. AU - Finenko, G. A. AU - Datsyk, N. A. PY - 2019/09/30 Y2 - 2024/03/28 TI - Gelatinous macroplankton of the open pelagial and shelf of the Black Sea: Distribution in autumn 2016 and interannual changes in biomass and abundance JF - Marine Biological Journal JA - mbj VL - 4 IS - 3 SE - Scientific communications DO - 10.21072/mbj.2019.04.3.01 UR - https://marine-biology.ru/mbj/article/view/177 SP - 3-14 AB - <p>The gelatinous macroplankton community of the Black Sea renews annually and functionates differently depending on the complicated system of trophic relations and interannual fluctuations of biotic and abiotic factors. Its monitoring is necessary for the evaluation of the current state and possible vectors of evolution of the whole pelagic ecosystem. For this purpose the data on the composition and distribution of gelatinous organisms were collected on the 89<sup>th</sup> cruise of the RV “Professor Vodyanitsky” (September – October of 2016) at 62 stations located in coastal areas and in the open sea to the south and southwest of Crimea. Samples were taken with the Bogorov – Rass net (inlet area of 0.5 m², mesh of 300 µm) using vertical net hauls from the bottom to the sea surface in the shallow shelf and from the lower boundary of the oxygen zone [according to the dissolved oxygen sensor CTD SBE plus (Sea Bird)] to the sea surface – in deepwater areas. <em>Aurelia aurita</em> and 3 ctenophore species (<em>Mnemiopsis leidyi</em>, <em>Pleurobrachia pileus</em>, and <em>Beroe ovata</em>) were present together in the 90 % of the samples (on 56 stations). In spite of some increase in average biomass of every species in deep sea areas, and, particularly, of <em>A. aurita</em> up to 260 g per m², there was no difference between the data of 2016 and 2010 (<em>p</em> &gt; 0.05). The abundance of <em>A. aurita</em> increased by about one order of magnitude (<em>p</em> &lt; 0.001); the abundance of <em>P. pileus</em> increased 2–5 times (<em>p</em> &lt; 0.001); of <em>B. ovata</em> – 3–15 times (<em>p</em> &lt; 0.01). <em>M. leidyi</em> abundance increased only at the outer Black Sea shelf; in other regions it could have been restricted by <em>B. ovata</em> predation. <em>A. aurita</em> linear specific growth rate in 2016 was one of the lowest for the last 15 years. Slow somatic growth of the jellyfish indicates unfavorable conditions for this species in 2016. However, the jellyfish biomass was higher than that of previous years because of the huge abundance of the spring generation. The weakening competition with planktivorous ctenophores may lead to even greater increase in the ecological valence of <em>A. aurita</em> among other gelatinous predators in the nearest future.</p> ER -