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The taxonomic composition and quantitative characteristics of zooplankton in the northeastern part of the Black Sea near the Taman coast in the summer-autumn period of 2018–2019 were studied. Zooplankton was represented mainly by eurythermic and thermophilic forms. All the discovered species and taxa are currently typical of the Black Sea, including the invading species: copepods Acartia tonsa, Oithona davisae, and combtails Mnemiopsis leidyi, Beroe ovata. The average number of zooplankton in 2018 ranged from 2.7–15.9 thousand copies/m3, the biomass – 0.02–0.14 g/m3; its indicators in 2019; they were lower, respectively, 2.0–5.6 thousand copies/m3 and 0.02–0.07 g/m3. These indicators were within the values recorded earlier, in 2013–2014. A significant part of the coastal zooplankton is meroplankton, which accounted for 5–69% of the population and 4–47% its biomass. O. davisae dominated amoung copepods. This speciest was leading in numbers in both years except June 2019. Despite the similarity of the taxonomic composition of zooplankton, the dominant species in terms of biomass differed by month in two years.

Сообщество желетелого макропланктона Чёрного моря обновляется ежегодно и функционирует по-разному в зависимости от сложной системы трофических отношений и межгодовых колебаний биотических и абиотических факторов. Мониторинг этого сообщества необходим для оценки современного состояния и векторов возможной эволюции всей пелагической экосистемы. С этой целью в ходе планктонных работ по программе 89-го рейса НИС «Профессор Водяницкий» (сентябрь ― октябрь 2016 г.) в прибрежных и открытых районах моря к югу и юго-западу от полуострова Крым на 62 станциях собраны данные по составу, численности, биомассе и распределению массовых видов желетелых. Пробы отбирали сетью Богорова ― Расса (площадь входного отверстия ― 0,5 м², ячея ― 300 мкм) методом тотальных вертикальных ловов от дна до поверхности моря в области мелководного шельфа и от нижней границы кислородной зоны [по данным зонда CTD SBE plus (Sea Bird)] до поверхности моря ― в его глубоководной части. Сцифомедуза Aurelia aurita (Linnaeus, 1758) и три вида гребневиков (Mnemiopsis leidyi A. Agassiz, 1865; Pleurobrachia pileus (O. F. Müller, 1776); Beroe ovata Bruguière, 1789) присутствовали совместно на 56 станциях. В глубоководных районах моря отмечено увеличение средней биомассы каждого из видов (A. aurita ― до 260 г·м−2). Достоверных различий между показателями 2016 и 2010 г. не обнаружено (p > 0,05), при этом численность медузы возросла почти на порядок (p < 0,001), P. pileus ― в 2–5 раз (p < 0,001), B. ovata ― в 3–15 раз (p < 0,01). Более высокая численность M. leidyi наблюдалась лишь на внешнем шельфе (p < 0,01); в других районах моря её увеличению могло помешать хищничество B. ovata. Скорость соматического роста медузы в 2016 г. была одной из самых низких за последние 15 лет. Опережающий рост численности желетелых по отношению к их биомассе свидетельствует о тотальном уменьшении размеров особей как в популяциях гребневиков, так и в популяции медузы. Низкая скорость соматического роста медузы указывает на неблагоприятные условия существования этого вида в 2016 г. Тем не менее из-за высокой численности особей весеннего поколения биомасса медузы была выше, чем в прежние годы. Вследствие ослабления конкуренции со стороны гребневиков-планктофагов, в перспективе на ближайшие годы следует ожидать ещё большего увеличения экологической валентности A. aurita среди желетелых хищников.

The study focuses on the impact of life excretion and mucus released by the "biological pollutants" invasive ctenophore Mnemiopsis leidyi and its predator Beroe ovata on the marine environment and lower trophic levels of the Black Sea ecosystem (bacteria, pico-phytoplankton, nano-autotrophic/heterotrophic flagellates, micro-phytoplankton, chlorophyll a, primary production (PP), micro-zooplankton). The chemical and biological variables were analysed in two sets of lab experiments with natural communities from mesotrophic (Gelendzhik) and eutrophic (Varna) coastal waters. While both species altered the chemical properties of experimental media, exerting structural and functional changes in the low food-web biological compartments, the results showed a stronger effect of B. ovata, most likely related to the measured higher rate of excretion and amount of released mucus. In addition the alterations in the Gelendzhik experiment were more pronounced, indicating that environmental implications on lower food-web are more conspicuous in mesotrophic than in eutrophic coastal waters.

In the second half of the XX century, Black Sea ecosystem has undergone significant changes: a number of storm winds and upwellings decreased, precipitation abundance increased, coastal waters salinity decreased, temperature increased; moreover, ctenophores invaded. As a result, in the late 1980s, Black Sea pelagic ecosystem abruptly got restructured. This research is based on the studies performed in 1965–1966 and 2007–2012 near Sevastopol (Western Crimea) using the remote sensing data. Analysis of satellite data over the past 20 years showed the presence of positive dynamics in surface water temperature in Sevastopol water area. In the mid-1960s, the annual bioluminescence was characterized by seasonal peaks of dinophytes luminescence. In recent years, this rhythm has changed due to ctenophores invasion. The increase in Mnemiopsis leidyi abundance leads to a decrease in bioluminescence of luminous microalgae being consumed by these ctenophores. Due to Beroe ovata invasion and reproduction, M. leidyi biomass decreased; as a result, bioluminescence increased.

The genus Beroe Browne, 1756 (Ctenophora, Beroidae) occurs worldwide, with 25 currently-described species. Because the genus is poorly studied, the definitive number of species is uncertain. Recently, a possible new Beroe species was suggested based on internal transcribed spacer 1 (ITS1) sequences from samples collected in Svalbard, Norway. Another species, Beroe ovata, was introduced to Europe from North America, initially in the Black Sea and subsequently (and possibly secondarily) into the Mediterranean and Baltic Seas. In areas where ctenophores have been introduced, they have often had significant detrimental ecological effects. The potential for other cryptic and/or undescribed Beroe species and history of spread of some species in the genus give reason for additional study. When alive, morphological hallmarks may be challenging to spot and photograph owing to the animals' transparency and near-constant motion. We sampled and analyzed 109 putative Beroe specimens from Europe, using morphological and molecular approaches. DNA analyses were conducted using cytochrome oxidase 1 and internal transcribed spacer sequences and, together with published sequences from GenBank, phylogenetic relationships of the genus were explored. Our study suggests the presence of at least 5 genetic lineages of Beroe in Europe, of which 3 could be assigned to known species: Beroe gracilis Künne 1939; Beroe cucumis Fabricius, 1780; and Beroe ovata sensu Mayer, 1912. The other 2 lineages (here provisionally named Beroe "norvegica" and Beroe "anatoliensis") did not clearly coincide with any known species and might therefore reflect new species, but confirmation of this requires further study.

Abundances, biomasses, size structures, and reproduction rates of the comb jellies Mnemiopsis leidyi and Beroe ovata were studied in the shelf area of the Black Sea near Sevastopol in 2013–2014. Longterm data on the population development were analyzed. The peculiar feature of M. leidyi development in recent years is a shift of its development to an earlier time of the season and a significant decrease in its reproduction rate: in the summer months in 2014, the average reproduction rate of adult ctenophores (30–70 mm) constituted only 20% of that in 2004. Such shift was related to the increase in temperature in the upper homogeneous layer, which, in turn, resulted in a decrease in its feeding rate.

Background The development and management of shelf-sea ecosystems require a holistic understanding of the factors that influence the zooplankton structure and ecosystem functions. The Black Sea is an example of such areas influenced by eutrophication, overfishing, climate variability, invasions of the ctenophores Mnemiopsis leidyi followed by Beroe ovata. Thus, there is a set of principal factors which may influence and explain periodicities in the Black Sea ecosystem. Methods We analysed a total of 918 samples taken from 1991 to 2017 with intervals of 10 days. Taxa were identified to species, their abundance and biomass were calculated. We tested 12 environmental factors, which may explain zooplankton distribution: temperature, productivity-linked factors (surface chlorophyll as a proxi), wind, turbidity, lowest winter temperature, and concentration of the ctenophore M. leidyi. We used canonical correspondence analyses to find the dominant environmental factors and further regression analyses to retrieve dependences of plankton biomass on the major factors. Periodicities were assessed with the use of the Continuous wavelet transform and tested with use of One-way ANOSIM and PERMANOVA. The distances between ecosystem states in different years were assessed using non-metric multidimensional scaling. Results Currently, temperature and productivity are the major environmental factors driving zooplankton dynamics. Not long ago, before 1999, abundance of M. leidyi was one of the major factors explaining the zooplankton variance. Spectral analysis of species abundances revealed a 4-year transitional period in 1999–2002 (not reported before) when ecosystem adapted to a new invader B. ovata. Statistically robust 2- and 3-year periodicities were retrieved for most plankton taxa and some benthic larvae. We found robust correlations between temperature and surface chlorophyll concentration on one side and plankton abundances and biomass on the other, and retrieved multivariate regressions, which may have a prognostic value.

Желетелые хищники ― важнейший компонент экосистемы Чёрного моря. Несмотря на многочисленные исследования различных аспектов их биологии (горизонтального и вертикального распределения, биоэнергетических показателей роста и трансформации энергии на организменном и популяционном уровнях) сведения о состоянии популяций и их функционировании в зимний период остаются крайне скудными. В настоящей работе численность, биомасса, размерная структура желетелых хищников (медузы Aurelia aurita, гребневиков Mnemiopsis leidyi, Beroe ovata и Pleurobrachia pileus) и интенсивность питания двух доминирующих видов (A. aurita, M. leidyi) исследованы на 17 станциях на шельфе Крыма в зимний период 2016 г. Сбор материала осуществляли модифицированной сетью Богорова ― Расса с диаметром входного отверстия 80 см, ячеëй 300 мкм, которой производили вертикальные траления от дна (10–100 м) до поверхности. Биомасса A. aurita, доминирующего в это время вида желетелых, изменялась в пределах 30–1990 г·м-2 с более высокими величинами в южных районах. Биомасса других видов желетелых была значительно ниже (максимальные величины — 170 г·м-2 для M. leidyi, и 60 г·м-2 для P. pileus). Высокая биомасса B. ovata (85 г·м-2 ), сравнимая с летней величиной, отмечена на одной из станций в западной части шельфа. Достоверных различий в биомассе отдельных видов желетелых по районам не выявлено, за исключением различий в биомассе B. ovata между западным и южным районами (p < 0.01). Популяции A. aurita и M. leidyi состояли из взрослых особей, в то время как большую часть популяции B. ovata составляли неполовозрелые гребневики длиной 20–30 мм. Основным видом пищи были велигеры двустворчатых моллюсков у A. aurita и различные стадии Copepoda— у M. leidyi. Cуточные рационы медуз составляли 0.009–0.107, M. leidyi — 0.02–0.28 % C тела и были значительно ниже пищевых потребностей животных в данных температурных условиях.

Работа посвящена актуальной теме измерения реакции биолюминесцентного свечения планктонтов, используемой в качестве стандартизованного и надежного биофизического метода. Ранее нами показана видоспецифичность особенностей светоизлучения Mnemiopsis leidyi A. Agassiz, 1865 и Beroe ovata Mayer, 1912, изменение параметров их биолюминесценции (амплитуды, энергии, а также длительности светоизлучения) в зависимости от температурных, трофических и других условий. Целью настоящих исследований было выявление вариабельности свечения черноморского гребневика M. leidyi в процессе его регенерации после воздействия хищника ― B. ovata. Определение характеристик биолюминесценции гребневиков проводили при помощи лабораторного комплекса «Свет». Биолюминесценцию ктенофор исследовали методом механической и химической стимуляции. Установлено, что после повреждений гребневики с сохранённым статоцистом активно двигаются, при этом показатели их свечения минимальны: по амплитуде ― 17,08 квант·с−1·см−2 и 1,37 с при химической стимуляции и 14,85·108 квант·с−1·см−2 и 1,25 с при механическом воздействии соответственно. После полной регенерации происходит восстановление массы тела ктенофор до исходных значений и увеличение амплитуды их биолюминесценции до максимального уровня: (332,33 ± 16,61·108) при химической и (219,45 ± 10,97·108) квант·с−1·см−2 при механической стимуляциях. Сделаны предположения о факторах, влияющих на интенсивность регенерации ктенофор M. leidyi и вариабельность их свечения в продолжение этого процесса. Таким образом, показана возможность использования биолюминесценции для уточнения экологических особенностей данного вида.

For the first time record of Beroe ovata off Lattakia, Syria in 2019 together with its prey, Mnemiopsis leidyi A. Agassiz, 1865 is presented. Both species probably arrived in the Mediterranean Sea with ballast waters and currents from the Black Sea. They are non-native ctenophores for the Syrian coastal waters. However, while M. leidyi is a harmful invader, B. ovata is its predator, who controls population of M. leidyi by grazing. New findings of these ctenophores are important for evaluation of the scale of invasions and understanding their impact on the Mediterranean ecosystem.

International audience; We analyzed the main factors that controlled the prey-predator dynamics of two invasive ctenophores, Mnemiopsis leidyi and Beroe ovata in the Black Sea using a demographic model. We assessed the bottom up cascading effect from edible zooplankton to its consumer M. leidyi and its predator B. ovata. For these purposes, we used life cycles of both ctenophores (ova, larva, juvenile, transitional and adult stages), variability of annual phenology and physiological features obtained from our field observations and experiments made in the northeastern Black Sea over 27 years, combined with a long-term change in temperature and food availability for both ctenophores. Model outputs were compared with field observations. Then, model scenarios were tested to understand which environmental conditions control M. leidyi and B. ovate development. Using our model, we found that the maximum annual abundances of M. leidyi and B. ovata increased with mean springtime temperature and development of spring-early summer zooplankton which is important for creation of M. leidyi abundance and consequently development of B. ovate. An assessment with changing concentration of the M. leidyi food (i.e. zooplankton) at the time of its annual development changed the maximum annual values reached by M. leidyi, and consequently B. ovate. It was found that time of appearance of B. ovata had changed to May since 2012 with increasing temperature, and as a result M. leidyi did not have time to reach high abundance, being grazed by B. ovate already since May. Model results were qualitatively the same as those from long-term field observations. As a result, we obtained a model of two ctenophores interacting with total life structure: duration and scale of reproduction, growing from stage to stage, mortality, seasonal disappearance from water depending on temperature and prey availability. Similar analyses have never been done in the Black Sea and can be used for other seas where M. leidyi or both ctenophores invaded.

Between mid-December 2011 and mid-January 2012 an unusual mixture of ctenophores was observed and collected at Kerteminde harbor (Great Belt, Denmark). In addition to native zooplanktivorous species Pleurobrachia pileus (O.F. Muller, 1776) and Bolinopsis infundibulum (O.F. Muller, 1776), non-native zooplanktivorous Mnemiopsis leidyi A. Agissiz, 1865 and their predator Beroe cucumis Fabricius, 1780 that had earlier been recorded in the area, two more predators on zooplanktivorous ctenophores were recorded in inner Danish waters: Beroe ovata sensu Mayer and Beroe gracilis Kunne, 1939. The identity of B. ovata was confirmed using nuclear marker 18S. Identification of B. gracilis was based on morphology. The presence of the observed mixture of ctenophores in Great Belt may predict future faunal changes in Danish and perhaps other temperate coastal waters. Key words: genetic analyses, morphology, non-native species, Danish waters Introduction The occurrence of the invasive ctenophore

In October and November of 2010, the gelatinous macroplankton in the northwestern Black Sea and at the Crimean shelf was represented by the scyphozoan jellyfish Aurelia aurita, three species of ctenophores (Beroe ovata, Mnemiopsis leidyi, and Pleurobrachia pileus), and three species of hydromedusae. A. aurita was more common at the shelf, M. leidyi and P. pileus prevailed at the deeper sea stations, and B. ovata was almost ubiquitous with a biomass from below 1 to 49 g/m2A. aurita, which had an average biomass of 82–224 g/m2, was dominant at all the stations. M. leidyi, which had a biomass from below 1 to 115 g/m2, was recorded in October at only 14 of the 52 stations and in November at 20 of the 46 stations. The highest biomass of M. leidyi in October (105 to 116 g/m2) was recorded in the deep sea areas; in November, it was also the highest in these areas, but it reached at most 100 g/m2. The average daily ration of Aurelia ranged from 19.4 to 27.3 mg/m2 in October and from 7.0 to 17.2 mg/m2 in November; in both cases, it was insufficient to provide for the minimal physiological requirements. The average daily ration of the Mnemiopsis population (2.8–20.5 mg of zooplankton per m2) was invariably more than sufficient to provide for the minimal physiological requirements. Both predatory species together consumed less than 5% of the daily zooplankton production of the sea.

Many ecological-physiological characteristics of ctenophores-aliensMnemiopsis leidyi A. Agassiz, 1865 and Beroe ovata Mayer, 1912 are studied quite well because they play a very important ecological role in the Black Sea ecosystem. However, bioluminescence, one of the most important elements of the ctenophores ecology and its connection with feeding regime were not studied sufficiently. Experiments have shown that characteristics of the ctenophores bioluminescence differed considerably in dependence of food supplies. Thus, amplitude and light-emitting energy of the fed ctenophores B. ovata are maximal, 3 times more than analogical indices of the just-caught individuals and 4 times more than ones of starving individuals. More prolonged flash signal (to 3.5 s), which exceeds light-emitting duration of the starving individuals twice, can be registered from the fed ctenophores. Investigation of the M. leidyi bioluminescence has shown that amplitude and light-emitting energy of the just-caught ctenophores were two times more than those of the starving individuals. At the same time, light-emitting amplitude of the fed individuals is 6.5 times and light-emitting energy is 3 - 4 times higher than that of the just-caught ctenophores. The light-emitting duration of the starving and justcaught organisms is practically the same. The most prolonged signal is registered from the fed ctenophores—up to 2.8 s. The data obtained testify that characteristics of the ctenophores bioluminescence can be conditioned not only by nutritional value but by the composition of the food as well.

Beroe ovata Chamisso & Eysenhardt, 1821 Remarks: ��� Beroe forskali Chun ��� and ���larves de Beroe forskali ��� recorded by Seguin (1965) are B. ovata. Beroe cucumis from Cartagena Bay (Moncaleano & Ni��o 1976) is also considered as B. ovata. Distribution in South America: Atlantic Ocean, Colombia to Argentina, from 10��N to 42��S (Domaneschi 1976; Moncaleano & Ni��o 1976; Genzano & Zamponi 1993; Mianzan 1986, 1999; Oliveira & Migotto 2006; Oliveira et al. 2007; Nogueira Jr. 2012; Nogueira Jr. et al. 2015b). Habitat: euryhaline and neritic species, found in coastal and estuarine waters (Mianzan 1986; Oliveira & Migotto 2006)., Published as part of M. P. Oliveira 1,16, S P. Miranda 2, *,, Es W. Mianzan 10,, Ro E. Migotto 11,, Ne B. Nascimento 2,11, Eli Nogueira J��nior 12,, Er Qui��ones 13,, Izio Scarabino 14,, T��n Schiariti 10,, Io N. Stampar 15,, Tronolone 2, , Qu��ria B. & Onio C. Marques 2,11, 2016, Census of Cnidaria (Medusozoa) and Ctenophora from South American marine waters, pp. 1-256 in Zootaxa 4194 (1) on pages 211-212, DOI: 10.11646/zootaxa.4194.1.1

This survey examined the association between the hyperiid amphipod Hyperoche martinezii and ctenophores off the Argentinian coast (38°08′17″S, 57°31′18″W) through the evaluation of seasonality, prevalence and intensity of infection during an annual cycle. Medusae were also examined but only the ctenophores Mnemiopsis leidyi, Pleurobrachia pileus and Beroe ovata showed this association during the austral mid-spring to mid-summer. A total of 502 hyperiids were obtained; most (422 individuals) were larval stages, 53 juveniles and 27 adults. Mnemiopsis leidyi had the highest number of hyperiids with 98.6%, followed by P. pileus (0.80%), and B. ovata (0.60%). Total prevalence was 2.0 and intensity of infection ranged between 1 and 17 hyperiids per ctenophore. The host with highest prevalence was B. ovata (4.54), followed by M. leidyi (3.76) and P. pileus (0.1). Prevalence values had some correlations with the increase in the total length of B. ovata (r = 0.480, P = 0.006) and M. leidyi (r = 0.501, P < 0.001), and between total length and intensity in B. ovata (r = 0.425, P = 0.017). The hyperiid was found in different parts of the host body: larval stages were found in the canal close to the subtentacular comb row and the stomodeum, whereas juvenile/adult stages were observed with a resting posture on the external surface of the ctenophores. The known geographic distribution of H. martinezii was extended; this finding represents the addition of three new hosts for this hyperiid. Fil: Puente Tapia, Francisco Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Diaz Briz, Luciana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Schiariti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Gasca Serrano, Rebeca Adriana. El Colegio de la Frontera Sur; México Fil: Genzano, Gabriel Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Proje kapsaminda, Guneydogu Karadeniz’ de secilen bes istasyonda (Findikli, Pazar, Cayeli, Rize Merkez, Iyidere) mevsimsel olcekte plankton kepcesi kullanilarak vertikal ve horizontal cekimler yapilmistir. Arastirma 2014 ilkbahari ile 2015 kis mevsimi arasinda yurutulmustur. Yapilan orneklemeler sonucunda iki tur ctenophora ( Pleurobrachia pileus , Beroe ovata ) ve bir tur Scyphozoa ( Aurelia aurita ) orneklenilmistir. P. pileus ve A. aurita turlerinin vucut uzunluklari (cm) ile yas agirliklari (g) arasindaki iliskiler sirasiyla W=0.46*L 1.27 (R 2 =0.98, n=193), W=0.063*L 2.23 (R 2 =0.90, n=94) olarak belirlenmistir. Orneklenen turler ve m 2 ’ deki organizma sayilarina bakildiginda, vertikal orneklemeler icin sirasiyla P. pileus (Maksimum: Rize istasyonu, ilkbahar 184.41 birey/m 2 ) ve A. aurita (Maksimum: Iyidere istasyonu, ilkbahar 184.41 birey/ m 2 ) bireylerinin yogunlukta oldugu belirlenmistir. B. ovata ise yalnizca kis mevsiminde (8.38-16.76 birey/m 2 ) orneklenmistir. Jelimsi organizmalarin horizontal dagilimlarina bakildiginda vertikal orneklemelere gore yogunluklarinin daha dusuk oldugu tespit edilmistir. Turlerin horizontal dagilim ve yogunluklarina bakildiginda m 2 deki birey sayilari goz onune alindiginda A. aurita turlerinin yogunlukta oldugu belirlenmistir. Anahtar Kelimeler : Guneydogu Karadeniz, Jelimsi organizma, bolluk- dagilim Abstract Distribution and Abundance of Jellyfishes in the South Eastern Black Sea In this study, two ctenophores ( Pleurobrachia pileus , Beroe ovata ) and one scyphozoa ( Aurelia aurita ) were collected vertically and horizontally by using plankton net from five stations (Findikli, Pazar, Cayeli, Rize, Iyidere) between 2014 spring and 2015 winter in the South Eastern Black Sea. Length- weight relationships of P. pileus and A. aurita W=0.46*L 1.27 (R 2 =0.98, n=193), W=0.063*L 2.23 (R 2 =0.90, n=94) respectively. P. pileus (Max: Rize station, spring 184.41 ind/m 2 ) and A. aurita (Max: Iyidere station, spring 184.41 ind/m 2 ) were abundant in the water column. Beroe ovata was only found in winter (8.38-16.76 ind/m 2 ). Jellyfishes were less abundant compared to verticals distribution. A. aurita was the most abundant species in terms of horizontal distribution. Keywords : SouthEastern Black Sea, Jellyfish, abundance –distribution

Successful invasion of Mnemiopsis leidyi A. Agassiz, 1865 and Beroe ovata Mayer, 1912 into the Black Sea and their important role in this region pelagic ecosystem is stipulated mainly by the considerable eurythermy of these species. Many ecological-physiological characteristics of ctenophores—aliens are studied quite well. However, bioluminescence, one of the most important elements of the ctenophores ecology and the bioluminescence reaction temperature optimum for these individuals under different environment temperatures were not studied sufficiently. Therefore our researches in this scientific field are significant and conceptually novel for ctenophores ecology study. Experimental investigations were carried out in the period of 2008-2009 in the IBSS. Uni-sized (40 mm) ctenophores were collected in the Sevastopol coastal zone and divided in several groups, contained under different temperatures: from 10°C ± 1°C to 30°C ± 1°C. Ctenophore bioluminescence was investigated under chemical and mechanical stimulation. M. leidyi light emission maximal amplitude (1432.94 ± 71.64 × 108 quantum·s–1·cm–2) with duration of 3.54 ± 0.15 s is fixed under the temperature of 26°C ± 1°C. Temperature increase up to 30°C ± 1°C led to the 4 times decrease of the bioluminescence intensity. Under temperature decrease up to 10°C ± 1°C this parameter decreased 20 times (p B. ovata achieved maximal values under the temperature of 22°C ± 1°C (1150.12 ± 57.51 × 108 quantum·s–1·cm–2) with duration of 3.03 ± 0.15 s. The luminescence intensity decreased under the temperature increase to 30°C ± 1°C more than 20 times. Temperature decrease to the values of 10°C ± 1°C impacted decreasing the amplitude of bioluminescence up to the minimal –4.92 ± 0.22 × 108 quantum·s–1·cm–2. The data obtained testify that characteristics of the ctenophores bioluminescence can be conditioned not only by the modification the environment temperature but by the variability of their physiological condition.

The variability of the mesozooplankton stock in the shelf pelagic communities was studied in the late summer and autumn of 2006–2008. The plankton community’s structure and distribution were described for the shoreward transect (Gelendzhik city vicinity). The indirect and direct effect of the ctenophores Mnemiopsis leidyi and Beroe ovata on the mesozooplankton community was studied. The long-term changes in the meso- and macroplankton communities of the Black Sea were analyzed for the period of 2001–2008. The effects of the climatic factors, the water mass circulation, and the factors’ interplay on the mesozooplankton dynamics were assessed. Despite the wide range of the environmental conditions, the stock biomass of Mnemiopsis leidyi appeared to be quite stable within the studied period.

The spatial distributions of gelatinous organism were studied during three cruises in 2006-2007. These were the first such studies conducted in the southern Black Sea for last decade. Additionally, the different methods of estimating gelatinous organism biomass presently in use were compared and recent situation of pelagic fishery interacting with zooplankton in the Black Sea were overviewed. Biomasses and abundances of both invading Mnemiopsis leidyi, and the resident Aurelia aurita and Pleurobrachia pileus were remarkably reduced (total gelatinous biomass: 417-537 g m(-2) in May, June, and 150 g m(-2) in October) as compared with those before the 1997 with invasion Beroe ovata in the southern Black Sea. Specimens of B. ovata were detected only in October when individuals with lengths of 10-50 mm comprised 93% of its population. Length-weight based biomasses were significantly variable for all species depending on the size structure in time. Larger sized individuals (> 30 mm) of M. leidyi appeared as compared with those before year 1997. The ecosystem of the Black Sea has been suppressed both bottom-up through decreased eutrophication and top-down through reduced grazing on mesozooplankton by M. leidyi that are in turn controlled by grazing by B. ovata. The catch of anchovy was abruptly reduced to 120,000 tons due presumably to the considerably increased catch of its predator, the bonito (64,000 tons) in the year 2005.

Observations of ctenophore species were made in the Gulf of Trieste between 2003 and 2006. We examined native ctenophore species with special attention to representatives of the orders Lobata and Beroida, and we recorded among them two non-native ctenophores: Mnemiopsis leidyi A. Agassiz 1865 and Beroe ovata sensu Mayer, 1912. The validity of the Mediterranean species Beroe ovata is discussed. We determined that among the native species, it is not Beroe ovata but rather Beroe cucumis sensu Mayer, 1912 that occurs in the Mediterranean Sea.

The organic matter content in the eggs and early larvae of the ctenophores Mnemiopsis leidyi and Beroe ovata from the Black Sea was determined using the adapted microtechnique of dichromate oxidation. The content of organic matter in the eggs of M. leidyi (0.25 μg/indiv.) was 5 times less than in B. ovata (1.28 ± 0.29 μg/indiv.). The somatic content of organic matter was 0.25 ± 0.09 μg/indiv. (25.1 ± 8.3 μg/mg, wet wt) for 2-day-old larvae of M. leidyi (0.2–0.3 mm in body length) and 1.37 ± 0.19 μg/indiv. (67.1 ± 5.7 μg/mg wet wt) for larvae of B. ovata (0.4 mm in body length). The specific organic content of larvae of both species steadily decreased with an increase in ctenophore body size and weight, approaching 3–4 μg/mg of wet weight for 2 mm specimens of M. leidyi and 3–5 μg/mg of wet weight for 6 mm B. ovata. The specific organic content of early larvae was 20–30 times higher than that of adult ctenophores. The results of this investigation could be useful in the evaluation of the energy budget for somatic growth and generative production in these species. Calculations indicate that with specific wet weight growth rates of 0.43/day for M. leidyi larvae and 0.29/day for B. ovata larvae, their true organic increases are respectively 30 and 38% less, i.e., no more than 0.31/day for the former and 0.18/day for the latter species.

The lined sea anemone Edwardsiella lineata has evolved a derived parasitic life history that includes a novel body plan adapted for life inside its ctenophore hosts. Reputedly its sole host is the sea walnut, Mnemiopsis leidyi, a voracious planktivore and a seasonally abundant member of many pelagic ecosystems. However, we have observed substantially higher E. lineata prevalence in a second ctenophore species, the ctenophore predator Beroë ovata. The interplay among these 3 species has important conservation consequences as M. leidyi introductions are thought to be responsible for the severe depletion of numerous commercial fisheries in the Mediterranean basin, and both E. lineata and B. ovata have been proposed as biological controls for invasive M. leidyi. Over a 3-yr period (2004-2006), we collected 8,253 ctenophores from Woods Hole, Massachusetts, including M. leidyi, B. ovata, and a third ctenophore, Pleurobrachia pileus, and we recorded E. lineata infection frequencies, parasite load, and parasite location. We also conducted laboratory experiments to determine the likely mechanisms for parasite introduction and the effect of each host on parasite development. We observed peak E. lineata infection frequencies of 0% in P. pileus, 59% in M. leidyi, and 100% in B. ovata, suggesting that B. ovata could be an important natural host for E. lineata. However, in laboratory experiments, E. lineata larvae proved far more successful at infecting M. leidyi than B. ovata, and E. lineata parasites excised from M. leidyi exhibited greater developmental competence than parasites excised from B. ovata. Although we show that E. lineata is efficiently transferred from M. leidyi to B. ovata when the latter preys upon the former, we conclude that E. lineata larvae are not well adapted for parasitizing the latter species and that the E. lineata parasite is not well adapted for feeding in B. ovata; these developmental and ecological factors underlie the host specificity of this recently evolved parasite.

A new alien species Beroe ovata Mayer 1912 was recorded in the Aegean Sea. It is most likely that this species spread on the currents from the Black Sea. Beroe ovata is also alien to the Black Sea, where it was introduced in ballast waters from the Atlantic coastal area of the northern America. The species is established in the Black Sea and has decreased the population of another invaderMnemiopsis leidyi, which has favoured the recovery of the Black Sea ecosystem.We compare a new 1 species with the native species fam. Beroidae from the Mediterranean and predict its role in the ecosystem of the Aegean Sea using the Black Sea experience.