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This survey aimed to update the mesozooplankton community's existing database in the port of Rijeka. The port baseline survey protocol developed during the BALMAS project (2013 - 2016) served as the guideline for the sampling methodoloAgy of this study. The port of Rijeka is located in the Northern Adriatic Sea, its border is 100 m isobath. The Northern Adriatic Sea is characterized by the largest riverine contributions in the basin. The area of the port of Rijeka is enclosed, it is connected to the open sea in the western area which is quite narrow. Low-moderate easterly winds impact the port, water being blown out to the open sea. Average abundance values of the total net mesozooplankton ranged from a minimum of 2, 888 ind. m-3 at station RIbwB during the autumn period to a maximum of 99, 365 ind. m-3 at the same station RIbwB during the summer period. Copepods were the most abundant group throughout the study period, they dominated in all samples. The minimal copepod’s contribution to the total zooplankton was 56 %, during autumn at RIbwB station, while the maximal copepod’s contribution was 96 %, during spring at JPG28 station. The values of temperature, salinity, and total net zooplankton abundance were correlated with individual zooplankton groups during each season. Besides that, we also performed correlations between important zooplankton groups during each season. The highest numbers of significant correlations of temperature, salinity, and total net zooplankton with individual zooplankton groups were observed during spring and, the highest number of significant correlations between groups were observed during winter and spring. Average total zooplankton abundance and that of copepods have increased compared to previous research conducted in the same area in 2014.

Sezonska istraživanja mrežnog zooplanktona na ušću rijeke Neretve provedena su u siječnju, ožujku, srpnju i listopadu 2014. godine na dvije postaje tijekom četiri izlaska. Na obje postaje najveća ukupna brojnost zooplanktona bila je u listopadu (5433 jed. m-3 na postaji Ušće i 4058 jed. m-3 na postaji Osinj). Među veslonošcima, koji su bili dominantna skupina, najbrojniji su bili ciklopoidi, osim na postaji Ušće tijekom jeseni, kada su dominirali veći rašljoticalci te kalanoidni veslonošci. Dominantne vrste veslonožaca tijekom čitavog istraživanog razdoblja bile su: Paracalanus parvus, Clausocalanus pergens, Oithona nana i Euterpina acutifrons. Od ostalih zooplanktonskih skupina veću brojnost imale su ličinke školjkaša, i to na postaji Ušće u srpnju, kada je ova skupina dominirala u ukupnoj zajednici zooplanktona. Holoplankton dominira nad meroplanktonom tijekom čitavog istraživanog razdoblja. Taksonomski sastav zooplanktona uobičajen je za obalne vode južnog dijela istočnog Jadrana.

This paper presents a long-term experiment aiming to assess the feeding habits of a predatory marine gastropod species, Hexaplex trunculus (Linneaeus, 1758), under a range of pH conditions relevant in the context of ocean acidification (8.1 to 7.4). There was no significant relationship between the feeding rate (mussel week-1) and pH after a 40- week exposure (F1, 8=2.31, R2=0.25, p=0.25). After 60 weeks of exposure, no difference was observed between pH treatments in number of snails successfully reaching their food (success 66.7%), but the time to reach the food significantly differed (F2, 21=3.98, p=0.034) and showed a positive trend toward shorter duration (min) at lower pH. The data suggest that ocean acidification will not negatively impact feeding habits of this species.

Otok Lokrum, posebni rezervat šumske vegetacije od 1948., također je i područje ekološke mreže - područje očuvanja značajno za vrste i stanišne tipove (POVS) za ukupno osam stanišnih tipova uključujući pripadajući morski pojas. Naselja plemenite periske (Pinna nobilis, Linnaeus 1758) u podmorju Lokruma zabilježena su u području stanišnih tipova Naselja posidonije (Posidonion oceanicae), Grebeni i Preplavljene ili dijelom preplavljene morske špilje. U lokrumskom priobalju 2019. godine uočena je masovna smrtnost plemenitih periski koja je, slijedeći ovu pojavu u ostalim dijelovima Sredozemnog mora, zahvatila i hrvatsku obalu Jadrana. U sklopu projekta ̋Očuvanje plemenite periske (Pinna nobilis) u južnom dijelu Jadranskog mora ̋ od 2021. godine provode se mjere očuvanja preostalih jedinki te se postavljaju kolektori za prikupljanje mlađi. Osim toga, nastoji se informirati javnost o ovom problemu, stoga je provođenjem stručne prakse studenata Primijenjene ekologije mora Sveučilišta u Dubrovniku razvijen edukativni program o važnosti očuvanja plemenite periske za sve uzraste.

The objective of this research was to update the existing database of the mesozooplankton community in the port of Ploče. This should enable new insights into the impact of abiotic and biotic parameters on mesozooplankton composition and abundance in the studied area. The port of Ploče is located in the Neretva channel, where industrial infrastructure is scarce. The area is under the major influence of both the Neretva river and the highly saline oligotrophic waters of the open sea. Quantitative and qualitative analysis of mesozooplankton at least to order level was performed on samples obtained from three stations in the port of Ploče during four seasons, i.e. from autumn 2020 to summer 2021, as part of the ProtectAS project. The sampling methodology was in line with the port baseline survey protocol developed during the BALMAS project. Population density values of the total mesozooplankton ranged from a minimum of 926 ind. m-3 at station P3 (29.4.2021) to a maximum of 24, 810 ind. m-3 at station P1 (10.2.2021). Copepods were the dominant group throughout the study period, accounting for 80 % (during autumn at P3 station) to 98 % (during spring at P3 station) of the total mesozooplankton. We correlated the values of temperature, salinity and the total zooplankton with specific groups of zooplankton as well as the values of important zooplankton groups with each other. The highest number of significant correlations between abiotic and biotic parameters occurred during spring. Significant correlations between the total abundance and specific groups were evident throughout all seasons. Compared to previous research in the same area conducted in 2011, the population density values of all major zooplankton groups obtained during our research have increased.

This article reports on the characteristics of the population of the Mediterranean scallop (Pecten jacobaeus) in Valdibora Bay on the west coast of Istria, Croatia. Morphometric characteristics, meat index, condition index, gonadosomatic index, vertical distribution and density, and other organisms in the habitat were studied. The study was conducted from January to August 2015. Results indicate that a large proportion of scallops spawned in July. Meat and condition indices were highest in April and March. The depth at which the majority of the scallop population resides was 11 m. The average population density was 0.012 individuals m- 2.

International audience

The preliminary shell growth rate of Hexaplex trunculus (Linnaeus, 1758) after long-term exposure to a range of future ocean acidification conditions

Mrtvo more on the Lokrum Island consists of a pit hole and a submerged channel that connects the marine lake to the open sea. Despite the specificities of Mrtvo more geomorphological phenomenon which is under the EU ecological network Natura 2000 (habitat type 8330 - submerged or partially submerged sea caves), there is a lack of data considering macrozoobenthic species inhabiting this area. Aim of this research was to determine the composition and dynamic of macrozoobenthos in Mrtvo more and to determine whether there are seasonal changes in chemical composition of seawater. The research was carried out from June 2017 until June 2018, with 13 samplings being performed, species present in the supralittoral, mediolittoral and infralittoral area were recorded, abiotic factors were measured (temperature, salinity, dissolved oxygen concentration) and seawater samples were taken to chemical analysis for total ammonia nitrogen (TAN), nitrate (NO3-N) and nitrite nitrogen (NO2- N) and phosphate (PO4-P) concentrations. Mrtvo more is shallow, semi- enclosed area and as such is under more influence of atmospheric conditions. Changes in temperature and salinity are more rapid, especially during spring and autumn period. Dissolved oxygen concentration levels were mostly above 4 mg/dm3, except for the July and August when lowering of dissolved oxygen concentrations corresponded with higher sea temperatures and degradation of phytobenthic communities. This is the peak period of a tourist season, therefore, anthropogenic pressures are highest. TAN, NO3- N, NO2-N and PO4-P concentrations were determined with standard spectrophotometric methods and they are under allowed limits for the first quality waters according to Regulation on water classification (Official Gazette, NN/98 ; NN 137/08). Visual census method and identification keys were used to mark down and identify macrozoobenthic species in supralittoral, mediolittoral and infralittoral area. Average abundance of present species was estimated. A total of 25 taxa was recorded: 3 species of class Anthozoa, 6 species of class Gastropoda, 1 species of class Bivalvia, 2 species of class Polychaeta, 3 species of class Hexanauplia, 5 species of class Malacostraca, 1 species of class Echinoidea, 3 species of class Holothuroidea and 1 species of class Asteroidea. There were three species noted in the supralittoral zone, 17 species in mediolittoral and 10 species in the infralittoral zone, although some species inhabit both mediolittoral and infralittoral. During June, July and August there were high population mortalities of genus Patella Linnaeus 1758 recorded as well as withdrawal of some species from the mediolittoral to the infralittoral zone. Due to the partly isolated position of Mrtvo more marine lake, ecological conditions differ from conditions in the coastal area of the island, therefore stress caused by temperature and salinity changes is more expressed. Furthermore, seasonal anthropogenic pressures on such a small area with limited water exchange cause rising of stress levels for organisms inhabiting the marine lake. Data obtained from this research will contribute to the knowledge of biological and ecological characteristics of marine lake Mrtvo more as well as better and more successful management of Lokrum island protected area.

Marine snail Cerithium lividulum Risso 1826 (Gastropoda: Caenogastropoda) is one of the most abundant benthic species in marine lake Mrtvo more on Lokrum island, inhabiting rocky substrates covered in algae, in the intertidal zone. There is an extreme inter- and intraspecies morphological shell variability for the smaller species of genus Cerithium, which is making it difficult to define morphological characteristics of an individual species. There is a significant lack of data in the available literature on morphometric characteristics of snail Ceritihium lividulum, and individuals from Mrtvo more were identified according to the shape of protoconch (Garilli and Galleti, 2006 ; Evangelisti et al, 2016). The aim of this research was to contribute to the knowledge of morphometric shell characteristics - height (h) and width (w) and their relations. Measurements were carried out from September 2018 to May 2018 with caliper precision 0.05 mm, five times in total, in situ. There were at least 100 individuals in each sample. Recorded data were put into tables (Microsoft Excel) and analysed with statistical package Minitab. Population (n=519) mean shell height values ranged from 11.07 ± 0.51 mm to 16.09 ± 0.12 mm, while shell width ranged from 4.57 ± 0.16 mm to 6.06 ± 0.06 mm. Maximum and minimum values of shell height and width were recorded during sampling in September 2017 (hmax= 20.00 mm, hmin= 3.00 mm, wmax=7.00 mm, wmin=1.10 mm). Average shell height in population measures 15.52 mm, while average shell width measures 5.57 mm. The largest recorded individual measured 20.00 mm shell height, which is, according to the literature, the maximum size this species can reach. Most population (n=519) had shell height between 14.50 and 17.50 mm (64.1%), and width in a narrow range between 5.50 and 6.50 mm (54.1%). Only two individuals measured shell height more than 19.00 mm, and the same two individuals had shell width larger than 7.50 mm. There is a statistically significant difference between height and width (T-test ; p

The Island of Lokrum, a special nature reserve of forest vegetation is also an area of the Natura 2000 ecological network that includes marine area which extends approximately 150 m off the coast with three habitat types - Posidonia beds (Posidonion Oceanicae), reefs and submerged or partially submerged sea caves. According to the spatial planning documents, natural beaches are defined on different areas on the island. The increasing demand for visiting this protected area requires management actions that both conserve the natural heritage and ensure a quality visitor experience with special regard on marine recreational activites. During various field investigations of benthos and ichthyofauna and occasional sightings of jellyfish over the past few years, data were collected on the most common unpleasant encounters in the marine area of Lokrum Island, primarily at the sites of Portoč, Pod Manastijerom and Dead Sea. Organisms that have been reported can be classified from unpleasant to dangerous, depending on the consequences they may have on human health: Cnidaria / Scyphoza (Pelagia noctiluca (Forsskål, 1775), Cnidaria / Anthozoa (Anemonia sulcata (Pennant, 1777), Actinia equina (Linnaeus, 1758), Actinia cari Delle Chiaje, 1822), Annelida / Polychaeta (Hermodice carunculata (Pallas, 1766)), Echinodermata (Paracentrotus lividus (Lamarck, 1816), Arbacia lixula (Linnaeus, 1758), Sphaerechinus granularis (Lamarck, 1816)), Chordata /Pisces (Muraena helena Linnaeus, 1758, Uranoscopus scaber Linnaeus, 1758, Scorpaena porcus Linnaeus, 1758, Trachinus draco Linnaeus, 1758). Although fish species that have poisonous spines in fins, tail or gillnets, poisonous bite fish or tissue-poisoned fish are noted, inconvenient encounters with cnidarians (Anthozoa) are more likely. Some of these species are listed in the Red List of Threatened Species, published by the International Union for Conservation of Nature (IUCN). Data presented in this paper is a starting point for informing visitors about potential dangers and at the same time for interpreting the natural values of the marine area of Lokrum Island.

The aim of this research was to contribute to the knowledge of morphometric characteristics of mediolittoral sea snail Phorcus turbinatus (Born, 1778). Sampling was carried out eight times, comprehending all seasonal changes. The mean shell height of the sampled population (n = 668) was Sh = 13.57 mm, while the mean shell width was Sw = 14.51 mm. The smallest specimen measured 3.80 mm shell height and 4.30 mm shell width. The largest measured specimen had 26.85 mm shell height and 25.35 mm shell width. Positive allometric growth was determined, with specimens shell growing more in width until they reach sexual maturity, which is at approximately 11 mm, and more in height afterward.

Studija procjene stanja marikulture u Malostonskom zaljevu objedinila je sve dostupne podatke o ovom području proizašle iz znanstvenih i stručnih radova, programa praćenja i drugih dokumenata. Uz to, Studija otvara i neka nova pitanja vezana uz upravljanje ovim područjem te nudi pregled potrebnih aktivnosti i predlaže metodologiju za dobivanje podataka potrebnih za učinkovito i održivo upravljanje Malostonskim zaljevom.

Procjena utjecaja na okoliš potrebna je kod svih većih zahvata u prostoru tijekom čije izvedbe i kasnijeg korištenja dolazi do promjena u ekosustavima. Izrade studija utjecaja na okoliš temelje se na podacima koji bi prvenstveno trebali biti rezultat sveobuhvatnih znanstvenih istraživanja u području zahvata, što često nije slučaj. Cilj ovog rada je ukazati na nedostatke u postojećim studijama i predložiti mjere za kvalitetnije utvrđivanje postojećeg stanja i procjene utjecaja na ekosustave. Analiza javno dostupnih dokumenata o utjecaju na morski okoliš u Dubrovačko-neretvanskoj županiji tijekom posljednjeg desetljeća ukazuje na kronični nedostatak znanstvenih podataka proizašlih iz relevantnih istraživanja ekosustava. Pri izradi studija često se citiraju zastarjeli izvori, podaci dobiveni izvan područja zahvata ili rezultati jednokratnih mjerenja iz kojih nije moguće donositi općenite zaključke o ekološkim značajkama određenog područja. Za dobivanje relevantnih podataka i donošenje zaključaka o utjecajima na ekosustave nužna su sveobuhvatna i kontinuirana istraživanja.

Marine environment is the most diverse environment on Earth with a wide range of properties. Besides providing diverse habitats to millions of species and various taxonomic categories, oceans affect terrestrial habitats, biosphere and atmosphere, regulating weather patterns and climate. Littoral, comparatively narrow and the most accessible part of the marine environment is significantly affected by land. During the warm season, Lokrum is visited daily by numerous tourists and local inhabitants, who observe not only terrestrial environment but marine environment as well. Due to the island’s location and mostly accessible limestone rocks, it is a good site to observe common Adriatic marine organisms in situ. In supralittoral zone located above high tide sea level line, which can reach up to 5 meters of height on Lokrum, organisms are mostly distributed horizontally forming belts parallel to the shoreline. Cyanobacteria form visible dark coating on the rocks. Besides, it is inhabited by periwinkles, barnacles and other crustaceans. In midlittoral zone (here 0.5m - 1m), waves and tides generate fluctuations of environmental conditions, so organisms are adapted to an extreme environment – the shore is not always submerged and most organisms are desiccation resistant and distributed unevenly. Since the upper midlittoral zone is inhabited by limpets, periwinkles, barnacles, and other crustaceans, lower midlittoral zone is more diverse and densely populated. This is particularly visible on exposed shores of Lokrum which are covered by red calcareous algae and provide refuge to a variety of invertebrates from different phyla. Brown algae are also found on regular basis. The most common animals such as limpets, chitons, gastropods, anemone are attached to the substrate or their movement is limited, as in sea urchins, crabs and molluscs. It is also home to shrimps. Below the low water line, environmental conditions are more stable. Well-lit shallow rocks are covered with abundant population of macroalgae. They are mostly brown, but green and red algae which are home to many species such as mussels, sea urchins, worms, molluscs, sponges, can be observed in this zone. Aa large variety of fish looking for prey can be observed in this area, too. Well- lit shallow sandy bottoms are covered by patches or large areas of seagrass Posidonia oceanica, endemic to the Mediterranean region. The meadows of Posidonia provide habitat and nutrition for many species of fish, crustaceans, molluscs, bryozoans, as well as for many species of algae. It is the most diverse Mediterranean biocenosis. It is light dependent, produces large quantities of oxygen, and removes carbon dioxide from the atmosphere. Among many species which live in Posidonia meadows, relatively abundant population of the bivalve Pinna nobilis, fan mussel could be observed here by 2019. Interestingly, it was even found among rocks. It seems, however, that the mass mortality events occurring in the western Mediterranean caused by a parasite in 2016 and spreading eastwards, reached the Adriatic in spring of 2019, and affected Lokrums' population. Further comprehensive research is needed to determine the state of this endemic and endangered species. Owing to accessibility and specific environmental conditions, the littoral zone is vulnerable to human impact. However, Lokrum Island is a special nature reserve and an area of Natura 2000 ecological network, which provides opportunities for education, monitoring and research of marine ecosystems.

Prugasta ladinka, Chamelea gallina (Linnaeus, 1758), najbrojnija je vrsta školjkaša na ušću rijeke Neretve, iako je njezina populacija pod neprestanim pritiskom lokalnih ribara, turista i degradacije staništa. Cilj ovog rada bio je utvrditi promjene unutar populacije tijekom ljeta, doba naveće posjećenosti tog područja. Na pješčanjoj podlozi u donjem mediolitoralu na dvije lokacije su prikupljene ukupno 343 jedinke. Prosječna duljina jedinki smanjila se tijekom ljeta. Morfometrijski odnosi unutar populacije ne pokazuju znatna odstupanja od rezultata drugih istraživanja. Budući da je populacija pod očiglednim antropogenim pritiskom, potrebno je učinkovitije reguliranje i kontrola kako bi se osigurala mogućnost održivog izlova ove lokalno značajne vrste.

Owing to the rich biodiversity in the area, on the land as well as in the waters, Neretva delta has been not only agricultural site, but hunting and fishing area which is exposed to inadequate and non-selective use of weapons and gears. Since sandy sediment, without epiphytes and vegetation, provides habitat to the benthic biocenosis dominated by bivalve shellfish, the research on the biodiversity change of the bivalve shellfish Chamelea gallina Linnaeus 1758 community was conducted in 2003, 2004, and 2013-14.

Priroda otoka Lokruma, kao i dubrovačkog područja, predmet je brojnih istraživanja prirodoslovaca te odredište putopisaca. U svrhu dokumentiranja promjena u prirodi analizirani su znanstveni radovi i putopisi objavljeni još od 19. st., povezivanjem podataka o pojedinim stanišnim tipovima, vrstama i oceanološkim prilikama, važećih propisa iz područja zaštite prirode te recentnih radova i podataka o pritiscima. Zaključeno je da tada istaknute vrijednosti otoka danas čine međunarodno važne prirodne vrijednosti – stanišne tipove kao sastavni dio područja ekološke mreže: preplavljene ili dijelom preplavljene morske špilje, stijene i strmci (klifovi) mediteranskih obala obrasli endemičnim vrstama Limonium spp., karbonatne stijene sa hazmofitskom vegetacijom, vazdazelene šume česmine (Quercus ilex), mediteranske šume endemičnih borova. Nadalje, u radovima s kraja 19.st. opisana je pojava naplavljivanja biljnog materijala na obalu otoka Lokruma uslijed izloženosti južnim vjetrovima, dok je danas na istim lokacijama zabilježen i otpad iz mora uslijed globalnih pritisaka onečišćenja.

Tijekom siječnja, ožujka, svibnja, srpnja i listopada 2014. na postajama Ušće i Osinj na ušću rijeke Neretve istraživana je populacija mikrozooplanktona. Utvrđen je kvalitativni i kvantitativni sastav mikrozooplanktona te je, po prvi put, detaljnije prikazan odnos holoplanktona i meroplanktona u mikrofrakciji zooplanktona istraživanog područja. U svim uzorcima je zabilježena visoka prisutnost mukoznih agregata. Najveća brojnost mikrozooplanktona zabilježena je u svibnju na postaji Ušće (109 600 jed. m-3) te u srpnju na postaji Osinj (101 600 jed. m-3). Pronađene su sljedeće skupine mikrozooplanktona: Radiolaria, nelorikatni cilijati, Tintinnina, Cladocera, Copepoda (naupliji, kopepoditi i adultni mali kopepodi), Appendicularia, Pteropoda i ličinke bentoskih organizama. Dominantne skupine tijekom svih razdoblja bili su tintinini, nelorikatni cilijati i naupliji kopepoda. Među odraslim malim kopepodima dominirale su vrste Oithona nana i Oncaea media. Holoplankton je izrazito dominirao nad meroplanktonom na obje postaje tijekom cijelog istraživanog razdoblja s najvećim udjelom od 96, 67 % u listopadu i najmanjim udjelom od 85, 92 % u ožujku na postaji Ušće. Zbog vjerojatnosti brzih procesa u površinskim slojevima bila bi neophodna istraživanja u kraćim vremenskim razdobljima kojima bi se detaljnije istražio mikrozooplankton na ovom području.

The objective of this study was to determine whether the use of the electromagnetic field (EMF) of 50 Hz frequency and magnetic induction of 0.25 T could make for successful inactivation of a phytoplankton species, namely, marine microalgae Tetraselmis suecica and two bacteria strains ; Escherichia coli and Enterococcus faecalis. A number of laboratory electromagnetic field tolerance experiments with the selected organisms was performed ; each microorganism was treated for various lengths of time ; 1, 5 and 10 minutes, and in three various media with special regards to the conductivity. Bacteria were exposed to high, moderate and extremely low conductivity media, and the microalgae to high, low and extremely low conductivity media. The microbial viability was checked by counting the bacterial colony forming units, as well as alive and dead stained microalgae cells. It was found that the time of exposure to the EMF had a profound effect on the viability of T. suecica only in the extremely low conductivity media, and that it did not affect the viability of E. coli or E. faecalis at all.

Fish assemblage of small and shallow marine lake called the Dead Sea, on Lokrum Island (Dubrovnik, Croatia) were investigated from March to July 2017 by using visual census. This salt lake is actually a cave that collapsed in the geological past and is connected to the sea by a submerged channel. Lokrum Island is a special reserve of forest vegetation since 1948. Today the island (72 ha) and the sea-belt (approx. 150 m) are also Natura 2000 site which includes eight Natura 2000 habitat types. Geomorphological phenomenon Dead Sea with its pit hole and the channel that connects the marine lake to the open sea is a Natura 2000 habitat type - Submerged or partially submerged sea caves. In spite of long natural history tradition in this area, there are no data on the biodiversity of Dead Sea. At least 15 fish species were recorded, of which some are listed on the IUCN Red list of Threatened Species: Chromis chromis, Tripterygion melanurum, Muraena helena, Scorpaena porcus, Microlipophrys dalmatinus, Diplodus vulgaris, Diplodus puntazzo, Sparus aurata. The main geostructural characteristic of Dead Sea (openness to light) significantly affect the species richness and fish assemblage structures inside. The species richness generally displayed a similar pattern with the nearby outer sea, whereas the patterns of fish abundance varied among species. Rare and cave exclusive species were not reported from this preliminary study. Although the natural values of the Lokrum Island represent unique whole of land and sea, Public Institution Lokrum Reserve does not currently manage the entire sea area of Natura 2000 Lokrum site. Therefore, this preliminary data represent guidelines not only for fish fauna conservation, but also with implications for conservation and management of Natura 2000 marine habitat types of Lokrum Island.

During phytosociological research in the Neretva River Delta in July 2016, we have noted an abundant presence of species Myriophyllum heterophyllum Michx. (Haloragaceae) within vegetation of rooted leaf-floating macrophytes of the Nymphaeion alabae Oberd. 1957 alliance (the order Potamogetonetalia Koch 1926). The species is native to the North America. In Europe, It is present in nine countries: Austria, Belgium, France, Germany, Hungary, the Netherlands, Spain, Switzerland, and Northern Ireland. According to the data of the European and Mediterranean Plant Protection Organization (EPPO), Myriophyllum heterophyllum has the status of invasive species in the freshwater ecosystems since 2012. The species is used for ornamental purposes in aquariums and ponds. Reproduction occurs primarily through vegetative fragmentation and rhizome division, as well as by seeds remaining in the sediments. Myriophyllum heterophyllum’s habitats are freshwater ponds, lakes, ditches and all other standing and slow flowing waters. It can grow in waters up to depth of 1.8 m. Although its areal is still limited in Europe, it is considered an invasive species with a tendency of rapid expansion. According to recent knowledge, finding of this species in the lower Neretva River is also the first finding in Southeast Europe.

U okviru zadane teme festivala znanosti vrijeme, obrađen je pojam vremena s kronološkim i meteorološkim značenjem na primjeru nalaza kućice holoplanktonskog puža ljubičastog splavara Janthina janthina (Linnaeus, 1758) u uvali Portoč na otoku Lokrumu u svibnju 2016. tijekom uklanjanja otpada naplavljenog jakim vjetrom i strujama. Slijedeći prirodoslovnu misao prirodoslovca i muzealca Spiridona Brusine koji godine 1907. opisuje rijetko nađenu vrstu puža ljubičastog splavara zabilježenu na području otoka Lokruma 1868. i svoju suradnju s dubrovačkim franjevcem i prirodoslovcem Kuzmićem koji je istraživao malakofaunu Lokruma pregledno su prikazani podaci o nalazima roda Janthina u Sredozemju i Jadranu s posebnim osvrtom na prirodoslovne zbirke u Republici Hrvatskoj. Vrsta J. janthina se rijetko pronalazi u Jadranu, a nalazi su obično rezultat specifičnih vremenskih uvjeta – jakih južnih vjetrova …

A specimen of the violet snail Janthina janthina (Linnaeus, 1578) was collected in Portoč Bay, Lokrum Island, in May 2016, during the beach cleanup and removing of marine debris drift arising from strong winds. The first record of the raft snail J. janthina along the Eastern Adriatic coast was also noticed in the area of Lokrum Island in the middle of the 19th century.

Slatkovodni školjkaši (Bivalvia, Lamellibranchia, Unionoida) su primarni konzumenti koji imaju veliki utjecaj na strukturu i funkcioniranje ekosustava. Unatoč tome, slatkovodni školjkaši jadranskog slijeva, osobito njegovog neretvanskog dijela, dosad, gotovo uopće nisu proučavani. Tijekom istraživanja donjeg toka rijeke Neretve (Kuta, Desansko jezero, Crepina, Baćinska jezera, Hutovo blato - Krupa, Hutovo blato – Deransko jezero) pronađene su slikarska lisanka Unio pictorum (Linnaeus, 1758) i bezupka Anodonta cygnea (Linnaeus, 1758). Određeni su biometrijski parametri populacija ovih vrsta. Primijećeno je opadanje brojnosti jedinki u populacijama U. pictorum. Invazivna dalekoistočna vrsta Sinanodonta woodiana (Lea, 1834), koja se naselila širom Azije, Europe i Srednje Amerike, zabilježena u slijevu rijeke Bojane, zasad nije pronađena u istraživanom području. Ovim istraživanjem odredit će se status postojećih populacija i procijenit će se potencijalne promjene u budućnosti. Dat će se smjernice i predložiti mjere radi zaštite i očuvanja raznolikosti malakofaune donjeg toka rijeke Neretve.

U Hrvatskoj su zabilježene tri populacije ugrožene riječne kornjače, Mauremys rivulata (Valenciennes, 1833), na malim staništima sa značajnim utjecajem čovjeka, i to u području Konavoskog polja, u Stonskom polju i u Dubrovačkom primorju u Majkovima. Sukladno Uredbi o ekološkoj mreži kao područje očuvanja značajno za vrste i stanišne tipove (POVS) navodi se HR2000947 Gornji Majkovi – lokve: riječna kornjača M. rivulata. U Prostornom planu Dubrovačko-neretvanske županije predlaže se zaštiti lokalitet Gornji Majkovi – lokve u kategoriji posebnog rezervata sukladno Zakonu o zaštiti prirode. S ciljem procjene ugroženosti staništa vrste M. rivulata, te određivanja smjernica za očuvanje i upravljanje ovim područjem, tijekom 2013. obavljeno je istraživanje jedne lokve u Gornjim Majkovima. Istraživanje je uključivalo određivanje fizikalno-kemijskih parametara vode (količina amonijaka, nitrita, nitrata, fosfata, otopljenog kisika, pH vrijednost, temperatura, slanost, vodljivost) i koncentracije teških metala (Pb, Cd, Hg i As) u sedimentu i tkivu ribe Gambusia sp. iz lokve, u svrhu procjene antropogenog utjecaja i stupnja bioakumulacije metala u tkivima živih organizama. Uzorci vodea nalizirani su spektofotometrijski na ukupni amonijakalni dušik (TAN), nitrate (NO3), nitrite (NO2) i fosfate (PO4) standardiziranim metodama. Koncentracije Pb, Cd, Hg i As u sedimentu i tkivu veličinske skupine ribe (n=30) analizirane su prema metodi HRN EN 13657:2008. Sukladno rezultatima utvrđenih fizikalno-kemijskih parametara prema Uredbi o klasifikaciji voda, kojom se određuju vrste voda koje odgovaraju uvjetima kakvoće voda u smislu njihove opće ekološke funkcije, utvrđena je kategorizacija vode u lokvi. Obavljena je kemijska analiza vode te su analizirane koncentracije teških metala u sedimentu i u tkivu dviju veličinskih skupina riba (< 2 cm i > 2 cm). Iako dobiveni podaci pokazuju sezonske varijacije, ovo se područje može svrstati u područja s niskim antropogenim utjecajem.

Kemijski sastav kunjke (Arca noae) istraživan je mjesečno od prosinca 2001. do studenog 2002. u Malostonskom zaljevu. Svježe meso kunjke sastoji se u prosjeku od 77.61±1.86% vode i 22.39±1.86% suhe tvari, a suho od 89.04±2.17% organske i 10.96±2.17 % anorganske tvari. Sadržaj suhe tvari smanjuje se u zimskom razdoblju kada su temperature mora niže od 13 °C, a s proljetnim porastom temperature mora, u travnju dostiže najveću vrijednost. Promjene u sadržaju suhe tvari uglavnom su popraćene odgovarajućim promjenama u sadržaju organske tvari. Utvrđena je pozitivna korelacija anorganske tvari i saliniteta. S obzirom na kemijski sastav, kunjka je najbolja za konzumaciju u proljeće.

U radu su opisane promjene u sastavu populacija vrste Chamelea gallina L. 1758 na dvije postaje tijekom dvije godine, rast i starost, te reproduktivni ciklus i položaj unutar pripadajuće makrozoobentoske zajednice na području ušća rijeke Neretve koje je izloženo neprestanom antropogenom utjecaju. Tijekom istraživanja pronađena je dosad najveća jedinka, duga 52, 80 mm i to na postaji Osinj, na kojoj je populacija manje ugrožena od one na postaji Ušće, a također je i gušće naseljena. Na istraživanom području žive kućice do sedam godina starosti koje pokazuju brži rast od pripadnika iste vrste koji žive na drugim područjima (od Portugala i Španjolske, preko Italije, do Turske i Ukrajine). Istraživanjem reproduktivnog ciklusa utvrđeno je da omjer mužjaka i ženki iznosi 1, 3:1, hermafrodita nema. Na temelju izgleda gonada tijekom cijele godine, uspostavljena je skala prema kojoj su razvrstani stadiji gametogeneze. Iako su gametogeneza i sporadično otpuštanje gameta zabilježeni tijekom cijele godine, tek u kolovozu, nakon razdoblja intenzivnog mriješćenja koje traje od travnja do srpnja, započinje razdoblje sazrijevanja gameta. Neaktivna razdoblja nisu zabilježena. Na istraživanim postajama pronađeno je 45 vrsta mekušaca, od kojih 31 školjkaš, 13 puževa i jedan koponožac. Pet vrsta pronađeno je u svim uzorcima: školjkaši Angulus tenuis, Cerastoderma glaucum, C. gallina i Donax semistriatus te puž Cyclope pellucida, koji zajedno s pužem Nasarius reticulatus znatno utječu na kvantitavnu komponentu zajednice. Indeksi bioraznolikosti najviši su u proljeće, a najniži zimi.

C. gallina, one of 16 commercial shellfish species in Croatia, occupies sand and muddysand substrates and coexists with other bivalve species. Investigations were conducted from January, 2003 to January, 2005. Samples were collected by a dredge, from the intertidal south-east part of river Neretva estuary, unique sandy and shallow area, on monthly basis. The total length of each clam (of 5598 specimen) was measured to the nearest 0, 1 mm. Total abundance of individuals ranged from 12 ind./m2 in February, 2004 to 229 ind./m2 in January, 2005, the average abundance was 75 ind./m2. The mean length of all collected clams ranged from 11, 70 mm in May, 2003 to 21, 58 mm in January, 2003. Normal distributions were separated using Bhattacharya's method. Growth parameters were calculated from von Bertallanfy growth function of length frequencies (growth constant k=0950). On each sampling occasion 50 specimen of commercial size were collected in order to calculate condition indexes. The condition index was analyzed and calculated for the year 2003 and it was highest in June (46, 297), and the lowest in April (24, 270). Another 30 specimen were fixed in 6% formaldehyde and further processed for histological analysis. After coloration with hematoxylin and eosin, the results showed that there were 97 female and 130 males from the total of 232 specimens. Spawning was recorded to occur from January until the end of August, and it is pronounced from April until July. After September the regression period followed. The beginning of gametogenesis is recorded in October and November, after which the maturation of sex products followed. The first spawning event is recorded in January. During research, total of 64, mostly mollusc species were recorded.

The treatment of live organisms is of increasing interest in many biological processes. More often than not these organisms reside within a fluid environment, and one example is the directed use of organisms in a bioreactor to create a product. Excessive heat, radiation or fluid forces can be damaging. Contrary to the above example in which we want to aid an organisms survival by manipulating fluid environment, there are situations where we want to use hydrodynamic forces as the tool for the elimination of unwanted organism’s. An important example for such applications would be in the treatment of ballast waters. In the system investigated here fluid forces in a cyclonic system are used in order to eliminate unwanted organisms. However, regardless whether we want to use hydrodynamics forces for an organism’s benefits or disadvantage, the understanding and control of such forces is essential. This study is focused on understanding the action of those forces through the use of Computational Fluid Dynamics (CFD) in order to evaluate the environmental parameters that contribute to cell damage. Data has become available that characterises the damage exerted by different cyclonic systems on sea water organisms when pumped into a ship’s ballast tanks. The work therefore aims to identify lethal conditions in the flow and use CFD to explain the action. Reverse engineering of this technology will allow the design of better fluid handling systems for sensitive organisms.

Obraštaj kao biološki kompleks posljedica je naseljavanja i pričvršćivanja bentoskih organizama na podlogu. Površina podloge se nakon uronjavanja u more prekriva tankim glikoproteinskim slojem, tzv. biofilmom koji omogućuje naseljavanje bakterija, gljiva, praživotinja i ostalih mikroorganizama ; nakon toga slijedi naseljavanje beskralježnjaka. Početak naseljavanja značajno utječe na tijek razvoja obraštajne zajednice, jer organizmi koji se prvi nasele onemogućuju, smanjuju ili potiču naseljavanje drugih organizama, a kompeticija za prostor i hranu unutar zajednice, utječe na dominaciju pojedinih vrsta. U područjima komercijalnog uzgoja različitih vrsta morskih organizama obraštaj predstavlja velike poteškoće jer povećava potrebu za sustavom plutača i sidara i nepovoljno utječe na rast i preživljavanje školjkaša. Obiman obraštaj začepljuje mreže kaveza za uzgoj i sprječava protok vode, čime se znatno smanjuje produktivnost, a time i dobit. Obraštajni organizmi svojom masom pridonose oštećenjima mreže što također rezultira gubicima. Razvoj akvakulture i traženje "novih" komercijalnih vrsta uspostavio je mehanizam širenja stranih, ne samo uzročnika bolesti, već čak i nekih pelagičkih vrsta. Na uzgajalištima školjkaša u Malostonskom zaljevu, najveće poteškoće uzrokuju dvije vrste, serpulidni mnogočetinaš Pomatoceros triqueter, koji smanjuje komercijalnu vrijednost školjkaša i plaštenjak Ciona intestinalis, koji nepovoljno utječe na rast školjkaša, a svojom biomasom iziskuje dodatna ulaganja u sustav parkova. Utvrđeno je da se obje vrste naseljavaju tijekom cijele godine, neovisno o sezoni. Brojnost jedinki je varijabilna. Najviše jedinki obiju vrsta zabilježeno je u hladnijoj sezoni kad je i najmanja kompeticija ličinki ostalih bentoskih vrsta.

Hrvatski se uzgoj školjkaša temelji na prikupljanju mlađi iz prirodnih populacija na kolektore nakon čega slijedi jedna ili više faza prerade. Postupci prerade zahtijevaju povećanje cijene proizvodnje školjkaša pa se pristupilo eksperimentalnom uzgoju dagnji Mytilus galloprovincialis (Lamarck, 1819.) na cilindričnim kolektorima od mješavine polietilena na kojima bi se dagnja uzgajala od prihvaćanja do konzumne veličine. Kolektori su iz mora vađeni radi uzimanja uzoraka i zamjenjivani novima u razmacima od dva, četiri, šest mjeseci, a nakon toga su se uzimali uzorci kako bi se utvrdilo vrijeme potrebno za dostizanje komercijalne veličine. Jedinke dagnji M. galloprovincialis nađene su na kolektorima uronjenima u more 4, 6 i 12 mjeseci. Od uzoraka na četiri mjeseca uronjenim kolektorima najviše je jedinki bilo u uzorcima iz travnja na kolektorima uronjenim u prosincu, a najmanje u prosincu na kolektorima uronjenim u more u kolovozu. Najviše jedinki dagnji zabilježeno je u uzorcima s kolektora uronjenih u prosincu i izvađenih nakon 12 mjeseci. Na kolektorima uronjenima u prosincu, 6 mjeseci nakon postavljanja, srednja duljina 949 jedinki iznosila je 18, 59 mm. Godinu nakon postavljanja kolektora, srednja duljina 699 jedinki iznosila je 37, 11 mm, a jedinkama na kolektorima nakon 18 mjeseci 51, 46 mm, čime je dostignuta tržišna veličina. Dobiveni rezultati ukazuju na mogućnost pojednostavljenja uzgojnog ciklusa dagnji, a daljnja će istraživanja pokazati isplativost ovakvog načina uzgoja.

Kuæ ; ; ica Chamelea gallina je školjkaš razdvojenog spola koji naseljava obalna podruè ; ; ja pjeskovite ili pjeskovitomuljevite podloge na dubinama do 20 m. Dosti e spolnu zrelost u prvoj godini ivota, kad dostigne duljinu od 12 mm, ali se fekunditet poveæ ; ; ava tek nakon što preraste 20 mm duljine. Biološki ciklus je pod znaè ; ; ajnim utjecajem ekoloških parametara, osobito temperature. Kako bi se pridonijelo poznavanju populacije radi odr ivog prikupljanja ovog komercijalno znaè ; ; ajnog školjkaša, praæ ; ; en je spolni ciklus od sijeè ; ; nja 2003. do sijeè ; ; nja 2004. godine na podruè ; ; ju ušæ ; ; a rijeke Neretve. Uzorci spolno zrelih jedinki su uzimani jedanput mjeseè ; ; no, konzervirani u 6%-tnom formaldehidu radi izrade histoloških preparata bojanih hematoksilinom i eozinom radi utvrð ; ; ivanja spolnog sastava, ciklusa sazrijevanja gonada i vremena razmno avanja. Od ukupno 232 jedinke, utvrð ; ; eno je 97 enki i 130 mu jaka, a za pet jedinki nije bilo moguæ ; ; e. Postojanje hermafrodita nije utvrð ; ; eno. Preliminarnim istra ivanjima je utvrð ; ; eno da su gonade mu jaka i enki sinkronizirano sazrijevale. Mriještenje je zabilje eno od sijeè ; ; nja do kraja kolovoza, a najizra enije je od travnja do srpnja. Od rujna slijedi razdoblje regresije. Poè ; ; etak gametogeneze zabilje en je u listopadu i studenom, nakon è ; ; ega slijedi sazrijevanje spolnih produkata, a prvo mriještenje je zabilje eno u sijeè ; ; nju.

The major part (about 74%) of Adriatic Sea coast belongs to Croatia but, because there is more import of cargo than export and the ballast water voulme dischared is low, Croatia plays only a minor role in today's ballast water situation in the Adriatic Sea. However, there is increased concern over ballast water in connection with the plans for oil pipeline integration projects in the region and oil export from port of Omišalj. Croatia currently faces ballast water issues in two respects: firstly, in relation to all of its export ports, where an examination on this matter is needed and both technical and regulatory solutions are required, and, secondly, in relation to a particular location – the port of Omišalj, which may experience an intensive and progressive tanker export traffic. Croatia is then left with three possible scenarios: 1.) no oil export, general traffic ; 2.) 5 million tonnes oil export + general traffic ; 3.) 15 million tonnes oil export + general traffic. The ballast water risk assessment is made up of several vectors: ballast water volume, quality and frequency of introduction. Ballast water volume and the number of vessels discharging ballast water will increase as a consequence of a natural growth in general vessel traffic re-corded in all Croatian ports during the last few years. Most of the vessel taffic and ballast water will remain local, from the Mediterranean and other Adriatic ports. But, if Omišalj becomes an oil export port, the ballast water volume will increase drastically. The majority of the ballast waters will arrive from completely different locations, probably from North America and North-West Europe. Huge changes in ballast water volume and origin will significantly increase the risk of introduction of nonnative species. Ballast Water Exchange is impossible in the Adriatic Sea due to depth and distance limitations. Therefore, alternate ballast water exchange zones must be considered, as well as land-based reception facilities. Croatian authorities are planning the implementation of the IMO Ballast Water Management Convention, but first of all detailed monitoring programmes on exotic species in Adriatic Sea have to be conducted. Also, information regarding the potential impacts of invaders and risk assessments are needed to identify vessels from critical areas. A precautionary approach in order to prevent unwanted impacts needs to be given high priority because certain invaders may cause negative influence on coastal environments, but also on two very important sectors in Croatia - tourism and fisheries. Creation of a regional network including all countries along the Adriatic sea is needed for a mutual benefit of all involved parties and for avoiding duplication of efforts and research. Hopefully, regional efforts will result in a minimization of future species introductions and preservation of the Adriatic Sea.

Spužve su najjednostavnije građene mnogostanične životinje. Nespolno razmnožavanje i velika sposobnost regeneracije osobine su koje olakšavaju njihov uzgoj. Hrane se filtriranjem čestica suspendiranih u moru pa je uzgoj spužava djelatnost koja ne onečišćuje okoliš, a može koristiti i za smanjenje negativnog utjecaja drugih akvakulturnih djelatnosti. Prirodne populacije spužava u Sredozemnom moru ugrožene su nepravilnim izlovom pa njihov uzgoj predstavlja moguće rješenje za obnovu i očuvanje postojećih prirodnih populacija.

Educational programme Lokrum island hidden colours was developed as a part of the Technical Museum Nikola Tesla exhibition Nature — the Laboratory of Colours. The exhibition represents the traditional knowledge of the use of natural dyes of mineral, plant and animal origins in the household in the far south of Croatia from Pelješac and Primorje to Konavle. Field research of this traditional knowledge was carried out during 2015 and 2016. Over 60 interviewees participated. The application of natural dyes in the household, especially the painting of walls, eggs at Easter time, clothing, fishing nets and as hair dye preparation was recorded. The most common plants used for obtaining dyes in the Dubrovnik region are: Pinus halepensis Mill., Allium cepa L., Rubia peregrina L., Chamomilla recutita (L.) Rauschert, Juglans regia L., Crocus sp., Fraxinus ornus L., Punica granatum L. The use of calx (quicklime) was also recorded. Each individual can contribute to the restoration of traditional knowledge, and the support of professionals and institutions, which can provide impetus with their educational programmes, is particularly important. Therefore, in order to enable the involvement of visitors in the preservation of natural and cultural heritage, the museum educator and curator, scientists in the field of natural and technical sciences and the expert on nature protection participated in the design of educational programme. It is designed with special attention to the preservation of habitats and biodiversity of Lokrum island and is intended for different target groups, from preschool children to senior citizens ; from locals to visitors to the island of Lokrum. The implementation of this programme on Lokrum island has been taking place since 2017 as a supplement to the respective exhibition staged in the Ethnographic Museum in Dubrovnik. Namely, the visitors had the opportunity to visit the exhibition with the expert guidance of the curator, after which the programme continued on Lokrum island within the framework of interdisciplinary workshops. These included short presentations, expert tours, fieldwork and determination of individual plant species, as well as elements of laboratory work and art workshops using natural dyes. During the workshops on Lokrum, a museum’s educational printed material was also used - a workbook as a supplement to the exhibition catalogue. Although the exhibition at the Ethnographic Museum was staged in 2017, the program continued successfully on Lokrum, confirming the role of the protected special reserve Lokrum Island as an active area in educational activities. Given the interest, especially in primary and secondary school teaching, it can also be concluded that this topic contributes to the protection of nature and the revival of traditional knowledge that is particularly relevant to the local community.