Dodatni nalaz alohtone vrste veslonošca Pseudodiaptomus marinus (Sato, 1913) u Jadranskom moru

The Indo-Pacific egg-carrying copepod Pseudodiaptomus marinus Sato, 1913 was recorded for the first time in the Port of Koper, Slovenia (Gulf of Trieste) in February 2015. This is the fourth finding of this species in the Mediterranean Sea, and the third for the Adriatic Sea. A rather high abundance of 73 ind. m-3 was recorded, which is considerably higher than previous findings in the Adriatic. Maritime transport is presumed to be the main cause of its introduction, primarily through ballast water release. Repeat sampling in May confirmed the presence of this copepod, indicating the possibility that the species has established a stable population in the Port of Koper.Indo-pacifička vrsta veslonošca Pseudodiaptomus marinus je po prvi put zabilježena u veljači 2015. godine u luci Kopar, Slovenija. Ovo je četvrti nalaz ove vrste u Sredozemnom moru, od kojih su tri u Jadranskom moru. Utvrđene su visoke vrijednosti od 73 ind. m-3, znatno više od prije zabilježenih za Jadran. Smatramo da je morski transport glavni uzrok unosa ovog veslonošca, prvenstveno putem balastnih voda. Ponovljenim uzorkovanjem u svibnju na istoj postaju potvrđeno je njegova stalna prisutnost što ukazuje na mogućnost uspostavljanja stabilne populacije u luci Kopa

The Structure of Zooplankton Population in the Jabuka Pit Area (Eastern Mediterranean)

The paper presents data on the structure of total zooplankton according to comparison of microfraction and mesofraction of quantitatively important zooplankton groups in the Jabuka Pit region. Research work was carried out during six cruises from 1986 to 1992 in the framework of the Adriatic Scientific Coordinating Programme (ASCOP). The samples were collected by vertical tows in three layers (50 to 0 meters, 100 to 50 meters and bottom to 100 meters). The microzooplankton was sampled with a 53 µm Nansen net equipped with a closing device and mesozooplankton with a Juday-Bogorov 250 µm net. There was no significant difference in zooplankton abundances between the eastern and western part of Jabuka Pit. The differences in the vertical distribution pattern, precisely between the surface and near the bottom samples were significant. Qualitative composition of some of the zooplankton groups differ between the western and eastern part of the Pit primarily due to the appearance of oceanic species in its eastern part, carried with mediterranean and south Adriatic water masses. This influence was most pronounced in December 1986 and August 1992. It should be noted that in September 1987 and in August 1992, small Oithona and Oncaea genera’s copepods prevailed, whereas in December 1986, May 1987 and August 1990, the calanoids were the dominant group

Novačenje i sastav hrane mlađi cipla balavca Liza ramada (Risso, 1826) na ušću rijeke Neretve (istočni Jadran, Hrvatska)

The present paper describes the recruitment and food composition of thin-lipped grey mullet, Liza ramada (Risso, 1826) juveniles in the estuary of the Neretva River in the southeastern Adriatic. Thin-lipped mullet appeared in the Port of Ploče in February. The relationships between total length, standard length, and weight showed a remarkably good fit to the expected allometric model, with b=3 for total length. Twelve different animal food categories were identified. The greatest diversity was recorded in April at the Port of Ploče when 10 categories were present. In addition, six diatom taxa were noted. Harpacticoid copepods were the most common prey (39%) in these samples, followed by insects (32%) and cladocerans (12%). All other prey accounted for less than 4%. Insects represented 99% of prey in the stomachs of specimens sampled from the freshwater Crna Rijeka River. Thin-lipped mullet juveniles were not found on sandy beaches or natural bays around the port. It thus appears that juveniles find the port area to be a habitat with the favorable characteristics of a brackish water nursery: of predators, lower salinity, and high food availability. These all promote better survival and recruitment in this area of the Croatian Adriatic.U ovom radu opisuju se novačenje i sastav hrane mlađi cipla balavca Liza ramada na ušću rijeke Neretve u jugoistočnom Jadranu. Cipal balavac se pojavljuje u luci Ploče tijekom veljače. Odnosi između ukupne dužine, standardne dužine i mase pokazuju izuzetno dobro poklapanje s očekivanim alometrijskim modelom, za vrijednost alometrijskog koeficijenta b=3 za ukupnu dužinu. Određeno je dvanaest različitih kategorija hrane. Najveća raznolikost, 10 skupina plijena, je utvrđena u travnju u luci Ploče. Dodatno je utvrđeno 6 taksonomskih kategorija alga kremenjašica. Harpaktikoidni veslonošci su najčešći plijen (39%) mlađi cipla balavca, zatim slijede kukci (32%) i rašljoticalci (12%). Na sav ostali plijen otpada manje od 4%. Kukci predstavljaju 99% plijena utvrđenog u probavilima jedinki prikupljenih iz Crne rijeke. Mlađ cipla balavca nije utvrđena na pješčanim plažama i zaljevima šireg područja ušća Neretve. Smatra se da je brojnost mlađi cipla balavca u luci Ploče u svezi s povoljnim uvjetima staništa kao što su: manji broj predatora, niža slanost i veća količina dostupne hrane. Sve navedeno pogoduje uspješnijem novačenju cipla balavca u ovom dijelu hrvatskog Jadrana

Epiplanktonske zajednice u južnom Jadranu: višestruke trofičke razine na transektima jug – sjever i obala-otvoreno more

The epiplankton community was investigated during Meduza cruises along south - north and offshore – inshore transects in the middle and southern Adriatic in spring 2002. The diel and vertical distribution of heterotrophic bacteria, phytoplankton pigment composition, micro- and mesozooplankton were assessed. At most stations we observed a thermocline at approximately 20 m and a prominent chlorophyll a peak at about 70 m depth. The integrated phytoplankton and bacterial biomass were lower at the station in the central part of the southern Adriatic, and increased gradually towards middle Adriatic and towards coastal stations. Vertical profiles of both bacterial abundance and production showed a distinct peak in the surface layer. Bacterial abundance was high also in the layer of the deep chlorophyll a maximum. Higher bacterial production was associated with elevated abundance of pico- and nanoplankton feeding zooplankton indicating that bacterial populations were generally controlled by predation.Istraživanje površinskih zajednica planktona obavljena su u proljeće 2002. godine tijekom “Meduza” krstarenja srednjim i južnim Jadranom na transektima “jug-sjever” i “obala-otvoreno more”. Utvrđena je dnevna vertikalna raspodjela heterotrofnih bakterija, sastava pigmenata fitoplanktona, te mikrozooplanktona i mezozooplanktona. Na glavnini postaja nađena je termoklina na oko 20 m i izraženo visoke vrijednosti klorofila a na oko 70 m dubine. Intergrirana bakterijska i fitoplanktonska biomasa bila je manja na središnjoj postaji južnoga Jadrana, a postupno se povećavala prema postajama Palagruža i Jabučka kotlina kao i prema obalnim postajama. Vertikalna raspodjela bakterijske brojnosti i produkcije pokazala je izraziti maksimum u površinskom sloju. Bakterijska brojnost bila je velika u sloju dubokog maksimuma klorofila a. Veća bakterijska produkcija bila je u svezi s povišenom brojnošću zooplanktona koji se hrani piko i nanoplanktonom, što ukazuje da su veličine bakterijskih populacija generalno kontrolirane predacijom

Planktonski žarnjaci Boka-Kotorskog zaljeva, Crna Gora (južni Jadran)

Planktonic cnidarians were investigated at six stations in the Boka Kotorska Bay from March 2009 to June 2010 by vertical hauls of plankton net from bottom to surface. In total, 12 species of hydromedusae and six species of siphonophores were found. With the exception of the instant blooms of Obelia spp. (341 ind. m-3 in December), hydromedusae were generally less frequent and abundant: their average and median values rarely exceed 1 ind. m-3. On the contrary, siphonophores were both frequent and abundant. The most numerous were Muggiaea kochi, Muggiaea atlantica, and Sphaeronectes gracilis. Their total number was highest during the spring-summer period with a maximum of 38 ind. m-3 observed in May 2009 and April 2010. M. atlantica dominated in the more eutrophicated inner area, while M. kochi was more numerous in the outer area, highly influenced by open sea waters. This study confirms a shift of dominant species within the coastal calycophores in the Adriatic Sea observed from 1996: autochthonous M. kochi is progressively being replaced by allochthonous M. atlantica in the coastal waters, especially in the eutrophicated areas. This study provides a detailed report on the composition and abundance of the planktonic cnidarians community in this region, and should be considered as a baseline for future studies on gelatinous zooplankton.Istraživanje planktonskih žarnjaka obavljeno je na šest postaja Boka-kotorskog zaljeva od ožujka 2009. do lipnja 2010. Uzorci su sakupljeni vertikalnim potezima planktonske mreže od dna do površine. Ukupno je nađeno 12 vrsta hidromeduza i 6 vrsta sifonofora. S izuzetkom velikih nakupina vrste roda Obelia u prosincu 2009. (341 jed. m-3), prosječne vrijednosti hidromeduza rijetko su prelazile vrijednost od 1 jed. m-3. za razliku od hidromeduza, sifonofore su bile češće i brojnije, osobito u proljeće i ljeto. Najbrojnije su bile Muggiaea kochi, Muggiaea atlantica i Sphaeronectes gracilis. Najveća gustoća od 38 jed. m-3 utvrđena je u svibnju 2009 i ožujku 2010. godine. Vrsta M. atlantica je dominirala u eutroficiranom unutrašnjem dijelu zaljeva, dok je M. kochi bila brojnija u vanjskom dijelu zaljeva koji je pod jakim utjecajem otvorenog mora. Naša istraživanja su potvrdila dosadašnja saznanja za Jadransko more da u obalnim, osobito eutroficiranim područjima, novo pridošla sifonofora M. atlantica postaje dominatna u odnosu na autohtonu vrstu M. kochi. Ova istraživanja donose prve detaljne podatke o sastavu i brojnosti planktonskih žarnjaka Bokakotorskog zaljeva i predstavljaju osnovu za buduća istraživanja želatinoznog zooplanktona

In Situ Manipulation of Vertically Migrating Gelatinous Zooplankton Using Nighttime Blue-Water Scuba in the South-Central Adriatic Sea

Technological advance in undersea exploration (e.g. tethered cameras, remotely operated vehicles [ROVs], Autonomous Underwater Vehicles [AUVsG, and manned submersibles)have opened new windows into diversityand distribution of fragile gelatinous organisms in the vast mesopelagic realm(300 m-1000 m deep). While exstraordinary in expanding our view of its richness, mesopelagic exploration remains largely a look but don\u27t touch environment and this limits of our ability to understand these animals through physical manipulation relevant to the finer scales of the individual organism. We have been conducting a series of in situ observations and manipulations using blue-water SCUBA during the night at a 1, 200 m station centraly located in the southern Adriatic Sea. We report here on a suite of vertically migrating gelatinous animals, including the narcomedusa Solmissus albescens and the physonect siphonophores Forskalia formosa and Agalma elegans, whose ranges extend to the mesopelagic realm during the day, but reach SCUBA diving depths during the night. Our in situ approach combined with proximity to shore exploits the natural vertical migratory behavior of some mesopelagic species, and we therefore add to the widening spectrum of methods needed to evaluate these ecologically important yet difficult to study organisms

Nalazi meduze Aequorea cf. forskalea u Jadranskom moru: usporedba povijesnih i recentnih podataka

Jellyfish are becoming an increasingly important component of studies of the global marine environment, as their frequent mass phenomena affect ecosystem performance and have economic and health consequences. Recent research has focused primarily on mass occurrences of scyphozoans and ctenophores, while less attention has been paid to hydromedusae blooms, which can also have significant impacts on the marine ecosystem with economic consequences. Like many members of the Scyphozoa and Ctenophora, Aequorea species can be numerous and form blooms. Based on surveys from 2000 to 2020 and information provided by marine professionals, we examine the (multiannual) variability, seasonality, and spatial distribution patterns of the poorly studied temperate species Aequorea cf. forskalea (Hydrozoa: Leptothecata). We hypothesized that this macrogelatinous jellyfish with a bipartite life cycle (benthic polyps and planktonic medusae) is sensitive to seasonal and long-term temperature fluctuations, particularly because temperature has been shown to play a critical role in mediating transitions in the life cycle of cnidarians. The cold-water affinity of A. cf. forskalea was confirmed by a significant negative correlation with temperature and the most frequent occurrence during the winter-spring period. For the northern Adriatic (Gulf of Trieste), sea temperature data and semi-quantitative plankton data are available for the first decade of the 20th century, allowing comparison of the historical data (1900-1911) with our current data set. Compared to historical records, the current occurrence of A. cf. forskalea differs significantly. With the warming of the northern Adriatic Sea since the beginning of the 20th century, the current phenology of A. cf. forskalea has changed, probably related to the delayed production of medusae by hydroids in autumn, the absence of medusae in this season and their less frequent occurrence in winter.Meduze postaju sve važnija komponenta globalnog proučavanja morskog okoliša, budući da njihove česte masovne pojave utječu na održanje ekosustava, a imaju ekonomske i zdravstvene posljedice. Najnovija su istraživanja usmjerena prvenstveno na masovnu pojavu režnjaka (Scyphozoa) i rebraša (Ctenophora), dok se manje pažnje posvećuje masovnim pojavama hidromeduza, koje također mogu imati veliki utjecaj na morski ekosustav sa značajnim ekonomskim posljedicama. Poput mnogih pripadnika Scyphozoa i Ctenophora, vrste roda Aequorea se mogu javljati u visokim brojnostima te njihovu pojavu možemo opisati kao masovnu („bloom“). Na temelju podataka prikupljenih tijekom istraživanja Jadrana u razdoblju od 2000. do 2020. godine te informacija dobivenih od stručnjaka koji se bave istraživanjem mora, razmatrali smo višegodišnju i sezonsku varijabilnost kao i obrasce prostorne raspodjele slabo proučavane vrste Aequorea cf. forskalea (Hydrozoa: Leptothecata) koja nastanjuje umjerena klimatska područja. Pretpostavili smo da je ova makro-želatinozna meduza, s bipartitnim životnim ciklusom (bentoski polipi i planktonske meduze), osjetljiva na sezonske i dugoročne promjene temperaturne, budući da temperatura igra ključnu ulogu za izmjenu generacija u životnom ciklusu žarnjaka (Cnidaria). Afinitet A. cf. forskalea prema hladnoj morskoj vodi potvrđuje značajna negativna korelacija s temperaturom te učestalo pojavljivanje tijekom zimsko-proljetnog razdoblja. Podaci o temperaturi mora i abundancijama vrste su dostupni za sjeverni Jadran (Tršćanski zaljev) za prvo desetljeće 20. stoljeća, što je omogućilo usporedbu povijesnih podataka (1900.-1911.) s novim setom podataka. U usporedbi s povijesnim zapisima, recentna se pojava A. cf. forskalea značajno razlikuje. Sa zatopljenjem sjevernog dijela Jadranskog mora od početka 20. stoljeća se mijenja sadašnja fenologija vrste A. cf. forskalea, što je vjerojatno povezano sa zakašnjelom proizvodnjom meduza u jesen, izostankom tijekom jeseni i njihovom rjeđom pojavom tijekom zime