Fan mussel Pinna nobilis Linneaus, 1758 spat collection on \u27\u27Christmas tree\u27\u27 rope in the Mali Ston Bay area (South Adriatic Sea)

During November 2006 on a 500 m long experimentally placed \u27\u27Christmas tree\u27\u27 rope collector for juvenile mussels (Mytilus galloprovincialis Lamarck, 1819) placed the previous year a significant number of juvenile fan mussels (Pina nobilis Linnaeus, 1758) were observed. Live juvenile individuals (N=322) of P. nobilis with shell length from 17 to 93 mm were found in two sampling events. All juvenile fan mussels were found exclusively on deeper parts of the mussel rope. Observed population density was from 6 to 43 individuals per meter of the rope collector. The 120 smallest juveniles of P. nobilis were separated for the purpose of monitoring the growth rate in suspension, and the remaining juveniles were placed in the natural environment

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

Ingresija hidromeduse Neotima lucullana (della chiaje, 1822) u ekosustavu estuarija rijeke Neretve (jugoistočni Jadran, Hrvatska)

Hydromedusa Neotima lucullana is an endemic species of the Mediterranean Sea. In this study we document the first numerous and permanent occurrence of N. lucullana in the estuary of the Neretva River, an unusual habitat for this typical marine species. We provide COI barcode sequence of this species, which is also first genetic sequence ever published of N. lucullana. Weekly data on the occurrence and abundance of N. lucullana were obtained from reports and records of autonomous divers and local fishermen in the area from Opuzen to Metković from mid-June to the end of October 2021. The individuals were always located in the layer above the bottom with salinity between 35.2 and 38.2. The diameters of the jellyfish bells ranged from 15 mm to 72 mm, most of them between 40 mm and 58 mm. Differential development of the gonads was observed in all specimens larger than 25 mm. In mid-June, the specimens were common but solitary. A week later, the jellyfish were more frequent and in smaller aggregations. From late June to mid-September, the jellyfish were constantly observed in larger aggregations. Toward the autumn, the number of individuals gradually decreased, and by the last week of October, only single individuals were observed. Our results indicate significant changes in the ecosystem of the Neretva estuary and confirm the observed composition of zooplankton communities dominated by marine species in summer and autumn.Hidromeduza Neotima lucullana je endemska vrsta Sredozemnog mora. Ovim istraživanjem dokumentiramo prve zapise o brojnoj i dugotrajnoj pojavi meduze N. lucullana u estuariju rijeke Neretve, neobičnom staništu za ovu tipično morsku vrstu. U sklopu ovog istraživanja dobivena je sekvenca podjedinice i citokrom oksidaze (COI), što je ujedno i prva genetička sekvenca ikad objavljena vrste N. lucullana. Tjedni podaci o pojavi i brojnosti N. lucullana dobiveni su na osnovi izvještaja i zapisa autonomnih ronilaca i lokalnih ribara na području od Opuzena do Metkovića od sredine lipnja do kraja listopada 2021. Jedinke meduza su uvijek bile u sloju iznad dna unutar vrijednosti saliniteta između 35,2 i 38,2. Promjer zvona meduza kretao se od 15 mm do 72 mm, glavnina između 40 mm i 58 mm. Diferencijalni razvoj spolnih žlijezda uočen je kod svih primjeraka većih od 25 mm. Sredinom lipnja jedinke su bile uobičajene, ali prisutne pojedinačno. Tjedan dana kasnije, meduze su bile često viđene i u manjim skupinama. Od kraja lipnja do sredine rujna, meduze su bile prisutne u većim agregacijama. Broj jedinki postupno se smanjivao prema jeseni i samo pojedinačni primjerci bili su uočeni tijekom posljednjeg tjedna listopada. Naši rezultati ukazuju na znatne promjene ekosustava donjeg toka rijeke Neretve što potvrđuje zabilježen sastav zooplanktonskih zajednica u kojima dominiraju morske vrste tijekom ljeti i jeseni

Sastav i raspodjela zooplanktona duž obalnih i otvorenih voda Albanije (južni Jadran) u kasno proljeće

We present for the first time composition, numerical abundance and vertical structure of microand mesozooplankton in the Albanian coastal and open sea region. Zooplankton was sampled at six stations on the 75-km long continental shelf slope transect in May 2009. The most numerous microzooplankton were copepod nauplii (maximum: 39 ind. L-1), followed by calonoid and cyclopoid copepodites (maxima: 5 and 4 ind. L-1, respectively). The most abundant of fourteen tintinnid species was Tintinnopsis radix, found in the surface to 50 m layer. The species composition of the coastal and open sea mesozooplankton was similar to that previously reported for the south Adriatic Sea. The copepod Oithona similis was the dominant species at all stations, followed by Oithona plumifera, Acartia clausi, Paracalanus parvus, Oithona nana and cyclopoida-oncaeids at the shallower coastal stations, and Clausocalanus pergens, Oithona plumifera and Oithona nana offshore. Mesozooplankton diversity rose considerably from the coast to the open sea. Mesozooplankton abundance exhibited the opposite trend, with the maximum (2286 ind. m-3) noted at the shallowest station. Findings of typically open sea tintinnid and copepod species at the coastal station indicate the high influence of currents from the open sea area during our investigation. Our results suggest the low influence of fresh water on zooplankton population densities, even at the shallow stations where penetration of fresh water in the surface layers was notable.Po prvi put su prikazani sastav, abundancija i vertikalna struktura mikro- i mezozooplanktona u albanskim obalnim i otvorenim vodama. Istraživanje je obavljeno na šest postaja duž 75 km dugom transektu od šelfa do kontinentskog slaza. Najbrojniji predstavnici mikrozooplanktona su bili kopepodni naupliji (maksimum: 39 ind. L-1), iza kojih su slijedili kalanoidni i ciklopoidni kopepoditi. Od 14 zabilježenih vrsta tintinida, najbrojnija je bila vrsta Tintinnopsis radix, nađena od površine do 50 m dubine. Sastav zajednice mezozooplanktona obalnog i otvorenog mora u skladu je s prijašnjim istraživanjima južnog Jadrana. Kopepod Oithona similis bila je dominantna vrsta na svim istraživanim postajama. Na plićim postajama slijede je vrste Oithona plumifera, Acartia clausi, Paracalanus parvus, Oithona nana i cyclopoida-oncaeids, a u otvorenim vodama vrste Clausocalanus pergens, Oithona plumifera i Oithona nana. Bioraznolikost mezozooplanktona značajno raste od obale prema otvorenom moru. Nasuprot tome, najveća gustoća mezozooplanktona (2286 ind. m-3) zabilježena je na najplićoj postaji. Prisutnost karakterističnih vrsta tintinida i kopepoda otvorenog mora na obalnim postajama ukazuju na utjecaj struja otvorenog mora za vrijeme ovog istraživanja. Naši rezultati ukazuju da povećani upliv slatke vode nije znatno utjecao na gustoću zooplanktonskih populacija čak i na plitkim postajama gdje je prodor slatke vode u površinskim slojevima osobito izražen

The epiplankton community in the southern Adriatic: multiple trophic levels along the south - north and inshore-offshore gradients

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