Search

An inventory of phytoplankton diversity in 12 Adriatic ports was performed with the port baseline survey. Particular emphasis was put on the detection of harmful aquatic organisms and pathogens (HAOP) because of their negative impact on ecosystem, human health, and the economy. Phytoplanktonic HAOP are identified as species, either native or non-indigenous (NIS), which can trigger harmful algal blooms (HAB). A list of 691 taxa was prepared, and among them 52 were classified as HAB and five as NIS. Records of toxigenic NIS (Pseudo-nitzschia multistriata, Ostreopsis species including O. cf. ovata) indicate that the intrusion of non-native invasive phytoplankton species has already occurred in some Adriatic ports. The seasonal occurrence and abundance of HAOP offers a solid baseline for a monitoring design in ports in order to prevent ballast water uptake and possible expansion of HAOP outside their native region.

This chapter includes a review of the recent results regarding zooplankton in offshore Montenegrin waters (since 2009) and a comparison of these results with earlier surveys. The highest abundance of total zooplankton was determined at station E, close to the river Bojana, in the summer period reaching 74, 972 ind m 3. A lower density of total zooplankton was observed during the winter. The abundance of total zooplankton increased toward the southern part of Montenegrin waters and from offshore to coastal stations. Contrary to the abundance, biodiversity grew from the coastal to the offshore sites as well as from the southern to the northern part of Montenegrin waters. Thirteen groups and 126 mesozooplankton taxa were determined. Analysis of the 12-month monitoring revealed that copepods were the most dominant group with an average contribution of 79% and a maximum share of 99%. Copepods were the most diverse group with 44 determined taxa. The most dominant taxa were Onceaidae-like species with 17% share, followed by: Oithona nana (14%), Acartia (Acartiura) clausi and Euterpina acutifrons (10%), and Paracalanus parvus parvus (8.5%). Cladoceran species dominated during the summer period, but the average contribution was 10%. Noctiluca scintillans reached a maximum value of 6, 417 ind m 3 in August 2009 at A3 station. Seventeen taxa of hydromedusae and 11 species of siphonophorae were collected during the survey period. Chelophyes appendiculata was noted for the first time in Montenegrin waters. High abundances of meroplankton larvae were recorded in this area throughout the investigation period, representing 2.7% of the total mesozooplankton. Bivalve larvae generally constituted the majority of this population. Biodiversity indexes showed statistically significant difference by seasons and decreasing values from transect A to transect E but no statistical difference was found. Comparison of medians of coastal with offshore stations showed statistically significant difference for the Margalef’s index. The data presented here nevertheless suggest where limited sampling resources should be used to describe more confidently the functional role of the mesozooplankton community in the Montenegrin Adriatic offshore waters.

Marine aquaculture is one of the fastest growing industries in the world, with a long-term growing trend and wide opportunities for the development and dissemination of production. It is clear that seafood production is the future of the marine fisheries sector, especially in terms of preserving existing fish resources, repopulation and conservation of endangered species, developing innovations in breeding technologies, and supplying the market with quality farmed food throughout the year.

Plankton (ichthyo, zoo and phyto) communities were studied in the temperate shallow waters of the Port of Bar, one of the main cargo ports on the south-eastern Adriatic coast. Sampling was undertaken in February, April, June and October 2015 at 12 stations using the BALMAS Port Baseline Survey protocol. The research was conducted to determine the presence of invasive and potentially toxic plankton species in the port.The most dominant species of ichthyoplankton were eggs and larvae of families Engraulidae, Bothidae and Sparidae with a dominance of Engraulis encrasicolus , Arnoglossus laterna and Diplodus annularis . In addition to ichthyoplankton, sampling of phyto and zooplankton was performed to estimate the abundance and diversity of species. The most numerous zooplankton species throughout investigated period were Penilia avirostris , Euterpina acutifrons , Oithona nana , Acartia clausi, Centropages kroyeri, Paracalanus parvus , Oncaeidae and larvae of Bivalvia. One very unusual occurrence was the spawning of parrotfish Sparisoma cretense (Linnaeus, 1758), a species with Atlantic origin and tropical affinities, whose presence throughout the Mediterranean has shown an increasing trend over the last decade. The most dominant species of phytoplankton were the diatoms Chaetoceros affinis and Chaetoceros spp., Asterionellopsis glacialis, Pseudo-nitzschia spp ., Thalassionema nitzschioides , and dinoflagellates G ymnodinium spp. and Prorocentrum triestinum . The potentially toxic species from genus Pseudo- nitzschia reached an abundance of 10 4 cells L -1 . Toxic dinoflagellates Prorocentrum cordatum and P. micans reached values of 10 3 cells L -1 . Although there were no HAOP species found during the survey, presence of several potentially toxic and toxic phytoplankton species whose impact is not sufficiently known indicates the necessity of introduction of regular monitoring activities and definition of preventive protection measures.

Marine bioinvasions and other rapid biodiversity changes require today integrating existing monitoring tools with other complementary detection strategies to provide a more efficient management. Here we explored the efficacy of fishermen observations and traditional port surveys to effectively track the occurrence of both indigenous and non-indigenous megafauna in the Adriatic Sea. This consisted mainly of mobile taxa such as fishes, crustaceans and molluscs. Port surveys using traps and nets within 10 major Adriatic harbours, were compared with the information obtained from 153 interviews with local fishermen. Information gathered by traps and nets varied significantly and generally resulted of limited efficacy in exotic species detection. Interviews allowed tracking the occurrence of new species through time and space, providing complementary knowledge at the low cost. This combined approach improves our capability of being informed on the arrival of species of different origin, providing a more rational, improved basis for environmental management and decision making.

Ports are subject to a variety of anthropogenic impacts, and there is mounting evidence of faecal contamination through several routes. Yet, little is known about pollution in ports by faecal indicator bacteria (FIB). FIB spatio-temporal dynamics were assessed in 12 ports of the Adriatic Sea, a semi-enclosed basin under strong anthropogenic pressure, and their relationships with environmental variables were explored to gain insight into pollution sources. FIB were abundant in ports, often more so than in adjacent areas; their abundance patterns were related to salinity, oxygen, and nutrient levels. In addition, a molecular method, quantitative (q)PCR, was used to quantify FIB. qPCR enabled faster FIB determination and water quality monitoring that culture-based methods. These data provide robust baseline evidence of faecal contamination in ports and can be used to improve the management of routine port activities (dredging and ballast water exchange), having potential to spread pathogens in the sea.

Port baseline surveys (PBS) provide species inventories in and around ports, with a focus on non-indigenous species that may have been introduced by vessels, primarily via ballast water. PBS are an essential tool to support effective management strategies for non-indigenous as well as native harmful aquatic organisms and pathogens (HAOP). This paper describes the methodology of PBS that were conducted in 12 Adriatic ports. The PBS employed existing protocols that were adapted to meet the characteristics of the Adriatic sites. Their results are reported in several papers included in this special issue, each of which is devoted to a specific community. An overview of existing surveys protocols – which provide valuable support to decision-making and to design effective monitoring of non-indigenous species – is also supplied.

Phytoplankton assemblages and pigment distribution were determined in the transitional Boka Kotorska Bay. Samples were collected four times from three stations in the inner part of the Bay between April 2008 and March 2009. Microscopic analysis revealed that the phytoplankton was composed of marine diatoms, dinoflagellates, cryptophytes, chlorophytes and coccolithophorids. Aside from fucoxanthin as the dominant biomarker pigment, alloxanthin, 19′-hexanoyloxyfucoxanthin, peridinin and chlorophyll b provided indicative contributions. Fucoxanthin and alloxanthin showed significant correlation with the phytoplankton chlorophyll a biomass throughout the investigated period. In November 2008, the diatoms were outcompeted by coccolithophorids, which probably efficiently absorbed nutrients during a period of their reduced supply. Due to the reduced nutrient input, in the summer, the phytoplankton community in the Bay was composed mostly of marine dinoflagellates, cryptophytes, and chlorophytes., Prisutnost zajednica fitoplanktona i rasprostranjenost pigmenata utvrđivani su u tranzicijskim vodama Bokokotorskog zaljeva. Uzorci su prikupljeni četiri puta na tri lokaliteta u unutrašnjosti Zaljeva u periodu između travnja 2008. i ožujka 2009. godine. Mikroskopskom analizom utvrđeno je da fitoplankton čine morske dijatomeje, dinoflagelati, kriptofiti, klorofiti i kokolitoforidi. Pored fukoksantina kao dominantnog biomarkerskog pigmenta, bili su zastupljeni i aloksantin, 19′-heksanoiloksifukoksantin, peridinin i klorofil b‏. Fukoksantin i aloksantin su pokazali značajnu korelaciju sa klorofilom a kao indikatorom biomase fitoplanktona tijekom čitavog perioda ispitivanja. U studenom 2008. godine, dijatomeje su nadjačale kokolitoforide, koji su vjerovatno efikasno apsorbirali nutrijente tijekom perioda u kojem je njihova dostupnost bila smanjena. Kao rezultat smanjenog unosa nutrijenata, u ljetnom periodu, zajednicu fitoplanktona u Bokokotorskom zaljevu sačinjavali su uglavnom morski dinoflagelati, kriptofiti i klorofiti.

The goal of this paper was to explain variability of phytoplankton in a shallow coastal area in relation to physico-chemical parameters. Temporal variability and composition of phytoplankton were investigated in the Kotor Bay, a small bay located in the south-eastern part of the Adriatic Sea. Samplings were performed weekly from February 2008 to January 2009 at one station in the inner part of the Kotor Bay, at five depths (0 m, 2 m, 5 m, 10 m, 15 m). Phosphates, nitrites and nitrates ranged from values under the level of detection to the maximum values of 1.54, 1.53 and 23.91 µmol l−1, respectively. The phytoplankton biomass — represented by chlorophyll a concentration — ranged from 0.12 to 6.78 mg m−3, reaching a maximum in summer. Diatoms were present throughout the whole sampling period, reaching the highest abundance in March (3.42×105 cells l−1at surface). The peak of dinoflagellates in July (2.2×106 cells l−1 at surface) was due to a single species, Prorocentrum micans. The toxic dinoflagellate Dinophysis fortii occurred at a concentration of 2140 cells l−1 in May. The present results of phytoplankton assemblages and distribution provide valuable information for this part of the south-eastern Adriatic Sea where data is currently absent.

The Boka Kotorska bay, located in the SE part of Adriatic See, is influenced by great influx of fresh waters from numerous water streams and submarine springs. Seawater samples were taken from five depths (0, 2, 5, 10 and 15 m) weekly, at one station in Kotor bay, from March 2008 to February 2009. Nutrient salts varied widely, with maximum values 23.91 μmol dm−3 for nitrates, 1.52 μmol dm−3 nitrites and 0.77 μmol dm−3 for phosphates. Chlorophyll a concentration ranged from 0.12 to 11.13 mg m−3 and the highest value was measured in winter period of the year (February). It seems that the reason for this is the land-based nutrient input into the coastal area. According to the different criteria for nutrients and chlorophyll a concentration the area could be mesotrophic, and we could conclude that the natural eutrophication still prevails over the anthropogenic eutrophication in this part of the Adriatic Sea. This study should help in determining future data needs for monitoring of water quality and human and climate influence on the health of the bay.

Subsurface chlorophyll maximum (SCM) are common phenomena in variety of environmental, from fresh water, brackish water, estuaries, shelf areas, the coastal zone to open ocean. It is now known that the chlorophyll maximum at the subsurface layer occurs widely in water where the water column is stratified. In permanent stratified tropical water, therefore, the SCM is expected to be a year round phenomenon. In higher latitudes, where there are occasional vertical mixing of the water column due to seasonal surface cooling or strong winds, the SCM will be restricted during a particular period of the year, such as in the summer or between spring and autumn. The Boka Kotorska Bay is semi-enclosed basin, located in the south-easter Adriatic Sea (Mediterranean Sea). The weekly changes in chlorophyll a and physico-chemical parameters were investigated in the period September 2008 to March 2009. Maximum phytoplankton biomass (11.13 mg m -3 chlorophyll a) was observed on 2m depth in February nearly the pycnocline. The good correspondence of SCM with occurrence of nitrate clearly indicates that the phytoplankton that make up the SCM depended highly on nitrate, which is supplied mainly by diffusional process from depth below the SCM.

Compiling the available data collected over many years of research of Boka Kotorska Bay showed variability in terms of dynamics and abundance of phytoplankton organisms. The Boka Kotorska Bay is a relatively large (87 km2), semi-enclosed bay, located in the south-eastern part of the Adriatic Sea. In addition to human impact, significant inflow of freshwater from numerous karstic streams and submarine springs contributes to the unique ecological characteristics of the Bay, particularly in its inner part (the Kotor Bay). Based on the data presented for the Boka Kotorska Bay (the Kotor Bay) phytoplankton abundance reaches up to 107 cells/l. Diatoms are the phytoplankton group present throughout the year. In some researches conducted in the Boka Kotorska Bay diatoms abundance reaching up to 107 cells/l was recorded. Dominant species are typical of areas with higher eutrophication that prefer nutrient rich areas and are very good indicators of ecosystem conditions. Dinoflagellates are the second important group of microplankton, frequently found in the aquatorium of the Boka Kotorska Bay. Dinoflagellates are generally less represented than diatoms, both quantitatively and qualitatively. The maximal recorded phytoplankton values indicate changes that may lead to eutrophic conditions in the Bay ; however, it can be concluded that the Bay is still moderately trophic. According to the two trophic indices TRIX and Fp ratio natural eutrophication is still dominant over anthropogenic eutrophication in Boka Kotorska Bay.

This study includes a review of recently published results regarding zooplankton in the Boka Kotorska Bay (since 2009), and comparison of these results with earlier investigations. Non-loricate ciliates were the most numerous microzooplankton in spring 2013 (37%). Loricate ciliates (tintinnids) values were low and similar to those recorded in the open Adriatic Sea. However, their diversity was quite high: 20 estuarine–neritic and 26 species typical of the open sea were identified. Copepod nauplii were dominant metazoan microzooplankton component (32%). Seven phylums and 81 mesozooplankton taxa were determined. Copepods were the most dominant group. Among them, Oncaea–cyclopoids and Oithona nana were the dominant copepod taxa at all stations. Heterotrophic dinoflagellate Noctiluca scintillans and cladocera Penilia avirostris were often extremely numerous during warm seasons. Changes in the zooplankton community noted during recent investigations can be linked with the observed climate changes identified in the Adriatic and Mediterranean Sea since the 1990s, which are reflected in: (1) zooplankton high densities in the winter period with a lack of spring peak; (2) domination of small-size cyclopoid copepods and decreasing of contribution of neritic calanoid species; (3) prolongation of high Penilia avirostris abundance in the autumn period; (4) spreading of invasive siphonophorae Muggiaea atlantica in the inner part of the Bay; (5) frequent outbreaks of gelatinous zooplankton; and (6) The first registered bloom of the ctenophore Bolinopsis vitrea in the Mediterranean in spring 2014, having a major impact on the regular planktonic food web system.

Temporal and spatial distribution of pelagic tunicates appendicularians was studied at six stations in Boka Kotorska Bay from March 2009 to June 2010. There were found nine species at all. The most numerous pelagic tunicates were found in Tivat Bay. Higher abundance was noticed during spring months. Most numerous species were Oikopleura dioica, Oikopleura longicauda, Oikopleura fusiformis and Fritillaria pellucida. O. dioica was dominant during winter and spring, O. longicauda during warm period of the year. O. fusiformis was more abundant in autumn while F. pellucida was noticed more during winter. Species Oikopleura intermedia and Kowalevskia tenuis were found in Herceg Novi Bay only. Species Oikopleura gracilis, Fritillaria borealis, Fritillaria haplostoma were noticed as rare in all three bays. Temperature was the main hydrological factor which influenced the abundance of appendicularians. Chlorophyll a was the main biological factor as indicator of phytoplankton biomass that influenced the abundance of appendicularians, mainly O. longicauda and O. fusiformis. Absence of correlation of these factors with O. dioica indicates that abundance of these pelagic tunicates could be regulated by the presence of predator ctenophore, Bolinopsis vitrea.

During the last 50 years ecological changes were already noted in the northern Adriatic, and many species disappeared from this zone. Following concern about substantial changes in the northern Adriatic, in this study we present the comparative results of the composition and abundance of hydromedusan fauna of northern Adriatic, pointing to the possibility of species repopulating recent years. Presented data are results of investigations during three study periods: the first from 1999-2002, second from 2003-2007 and the third from 2009-2011. Our results clearly showed that the number of species and their abundance increase from the first to the third investigated period. We assume that some species were introduced by input currents in the northern Adriatic, which is confirmed by the increasing density of trachymedusa, but abundances of some species were several times higher than in previous records. Although the abundance of hydrozoan species vary during their life cycles, our high mean and maximum values of this metagenetic specimens could indicate the possibility of establishing stable populations in the area. These changes are consistent with the recent changes in the plankton composition and abundance, probably caused by a climatic forcing and recognized oligotrophication of the entire northern Adriatic.

The ctenophore Bolinopsis vitrea has been rarely observed in the Mediterranean Sea. A bloom of B. vitrea is here reported for the first time in the southern Adriatic Sea in the spring and summer of 2009, together with its effect on the plankton of Kotor Bay. Ctenophores were only found below 5 m depth, where the hydrographic conditions were more stable. Results of the investigation indicate that mass occurrence of B. vitrea could have a great impact on the Kotor Bay ecosystem. Their predation on copepods would reduce grazing pressure on phytoplankton, favouring an uncommon bloom of the latter. It is evident that B. vitrea are capable of altering rapidly the composition and biomass of coastal plankton communities when present in large masses. This first evidence of such events for this species may indicate changes in the functioning of marine ecosystems of the southern Adriatic.