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Fish, cephalopods and shellfish provide a healthy source of high-quality proteins, essential vitamins, minerals and polyunsaturated fatty acids. The beneficial effects of fish consumption on human health such as protection against coronary heart disease and certain cancer may be offset by fish decomposition and the formation of chemical contaminants such as biogenic amines. There are several toxicological effects of biogenic amines on humans, especially histamine. It is the causative agent of histamine or scombroid fish poisoning which is a significant public health problem. In individuals with diminished histamine detoxification, ingestion of even a low or moderate histamine- or tyramine-containing fish may lead to food intolerance. Biogenic amines such as putrescine, tyramine and cadaverine can potentiate histamine toxicity. Furthermore, dietary polyamine intake should be minimised in some cancer patients. Besides their potential toxicity, biogenic amines are used for the evaluation of hygienic quality ...

Biogenic amines in fish, fish products and shellfish: a review

Pseudo-nitzschia, Nitzschia, and domoic acid: New research since 2011.

. Analysis of 20-year time-series of the vertically averaged salinity and nutrient data in the Southern Adriatic shows that the two parameters are subject to strong decadal variability. In addition, it is documented that nutrient and salinity variations are out of phase. Nutrients in the Ionian and in the Adriatic vary in parallel except that generally the nutrient content in the Adriatic is lower than in the Ionian, a fact that has been attributed to primary producer consumption following the winter convective mixing. As shown earlier, North Ionian Gyre (NIG) changes its circulation sense on a decadal scale due to the Bimodal Oscillating System, i.e. the feedback mechanism between the Adriatic and Ionian. Cyclonic circulation causes a downwelling of the nitracline along the borders of the NIG and a decrease in the nutrient content of the water flowing into the Adriatic across the Otranto Strait, and vice versa. In addition, the highly oligotrophic central area of the Ionian shows annual blooms only during cyclonic NIG circulation. Inversion of the sense of the NIG results in the advection of Modified Atlantic Water or of the Levantine/Eastern Mediterranean waters in the Adriatic. Here, we show that the presence of allochtonous organisms from Atlantic/Western Mediterranean and Eastern Mediterranean/temperate zone in the Adriatic are concurrent with the anticyclonic and cyclonic circulations of the NIG, respectively. On the basis of the results presented, a revision of the theory of Adriatic ingressions formulated in the early 1950s is proposed.

/pdf/on-the-impact-of-the-bimodal-oscillating-system-bios-on-the-hzifz98itg.pdf

On the impact of the Bimodal Oscillating System (BiOS) on the biogeochemistry and biology of the Adriatic and Ionian Seas (Eastern Mediterranean)

The Catalan Sea, located between the eastern Iberian coast and the Balearic Islands, is a representative portion of the western Mediterranean basin and provides a valuable case study for climate change effects on Mediterranean ecosystems. Global warming is reflected regionally by a rise in sea level over the last century, an increase in surface temperature of around 1.1°C in the last 35 yr, a progressive salinisation of intermediate and deep waters and a strengthening of the stratification. A likely scenario of what we can expect in the Mediterranean Sea is a consider- able decrease in rainfall and wind, warmer surface waters and a prolonged stratification period. The effects on Mediterranean ecosystems are evident in: (1) a meridionalisation of the algal, inver- tebrate and vertebrate species, which favours the more thermophilic species over the temperate species; (2) mass mortality events of sessile invertebrates of the coralligenous communities owing to anomalous warm waters during the period when food is scarce; (3) increases in the smallest phytoplankton due to the prolongation of the water stratification period; (4) proliferation of gelati- nous carnivores, including jellyfish, due to the temperature rise and the lack of rainfall; (5) a faster acidification of seawater, compared with the global oceans, accompanied by a decrease in the capacity to absorb atmospheric CO2. In order to anticipate and mitigate these predicted changes, we recommend investing in research and observation, conserving areas that serve as indicators of climate change and reducing other anthropogenic pressures such as habitat destruction, over- fishing or pollution, which may act synergistically to accelerate these changes.

https://www.int-res.com/articles/cr2012/50/c050p001.pdf

Effects of climate change on Mediterranean marine ecosystems: the case of the Catalan Sea

SUMMARY
The aim of our research was to study the composition of Pseudo-nitzschia species during a period when neurotoxin domoic acid (DA) was present in shellfish. Sampling was conducted in Kastela Bay (Central Adriatic Sea), between November 2015 and January 2016. Concentrations of DA analyzed in various shellfish species were low, below the regulatory limit, while the highest abundance of Pseudo-nitzschia spp. reached 1.85 × 105 cells L−1 in the surface layer, at the beginning of November. Within the temperature and salinity range recorded during the investigated period, a positive correlation of Pseudo-nitzschia spp. abundance was recorded with temperature. Morphological analyses by scanning electron microscopy revealed the presence of five Pseudo-nitzschia species that had already been reported in the Adriatic Sea – P. calliantha, P. delicatissima, P. fraudulenta, P. pseudodelicatissima /P. cuspidata and P. subfraudulenta – as well as an unknown Pseudo-nitzschia sp. The composition of the Pseudo-nitzschia assemblage changed over the investigated period. The species P. pseudodelicatissima/P.cuspidata was found throughout the entire period and the highest diversity was noticed in January, when all six observed species were recorded. These results represent the first taxonomical investigation of the genus Pseudo-nitzschia in Kastela Bay, as well as the first report of DA in shellfish from this area.

Taxonomical diversity of Pseudo-nitzschia from the Central Adriatic Sea

Coccolithophore diversity in open waters of the middle Adriatic Sea in pre- and post-winter periods

The effects of farming on planktonic microbial communities were investigated at the coastal sea bass/sea bream farm in the oligotrophic middle Adriatic Sea. Analyses of nutrients, chlorophyll a, cyanobacteria (Prochlorococcus), heterotrophic bacteria and nanoflagellates (both pigmented and heterotrophic) were carried out on samples taken during six seasonal cruises at different water depths. Farming activity increased the natural concentrations of some nutrients (ammonium, nitrite, phosphate, dissolved inorganic nitrogen) and changed their seasonal pattern. The values still remained typical for oligotrophic environ-ments demonstrating no risk for eutrophication. Enhanced nutrient supply provoked an immediate increase in abundances of both autotrophic and heterotrophic microbial groups (except pigmented nanoflagellates) and chlorophyll a. The effect of farming was more visible for the heterotrophic microbial component. Results from this study reveal a potential common pattern of microbial response to farming in the oligotrophic environments. It also suggests the importance of heterotrophic microbial web in transferring the matter and energy released from the fish farms in nutrient poor environments.

Effects of fish farming on microbial planktonic communities in the middle Adriatic sea

Present study describes the phytoplankton community structure and phytoplankton abundance in three bays on the eastern Adriatic coast (Sibenik Bay, Kastela Bay and Mali Ston Bay) during 2005. The highest phytoplankton biomass (expressed as chlorophyll a) were recorded at one station in Sibenik Bay (4.73 mg m-3), and in Kastela Bay (2.79 mg m-3), while at all other stations recorded values were generally below 1 mg m-3. At the investigated area of Sibenik Bay a total of 114 phytoplankton taxa have been determined. The most diverse were diatoms with 61 and dinoflagellates with 37 taxa. Coccolithophorids contributed with 6, cryptophytes with 3, silicoflagellates, euglenophytes and chlorophytes with 2 taxa. In the area of Kastela Bay 193 phytoplankton taxa have been recorded. Dinoflagellate group was the most diverse with 92 taxa, followed by diatoms (80), coccolithophorids (9), silicoflagellates and euglenophytes (4), cryptophytes (2) and chlorophyte (1). In the area of Mali Ston Bay a total of 88 phytoplankton taxa have been found, with 39 diatoms, 36 dinoflagellates, 2 silicoflagellates, 4 coccolithophorids, 2 euglenophytes, 1 chllorophyte and 3 chrisophyte taxa. Abundance of dinoflagellates was very low in this area. Coccolithophorids contributed more to the community composition in Mali Ston Bay, then in other areas of research. A diverse microflagellate group was present in the whole area of investigation with a high frequency of findings. During the investigated period a relatively small number of monospecific blooms in all areas have been recorded. The largest numbers of taxa were recorded at stations that are under an influence of freshwater input from rivers and strong anthropogenic influence.

/pdf/population-structure-and-abundance-of-phytoplankton-in-three-3ph9rqz9wn.pdf

Živana Ninčević Gladan

Papers

Taxonomical diversity of Pseudo-nitzschia from the Central Adriatic Sea

Coccolithophore diversity in open waters of the middle Adriatic Sea in pre- and post-winter periods

Effects of fish farming on microbial planktonic communities in the middle Adriatic sea

Population structure and abundance of phytoplankton in three bays on the eastern Adriatic coast: Šibenik Bay, Kaštela Bay and Mali Ston Bay

Impact of water column stability dynamics on the succession of plankton food web types in the offshore area of the Adriatic Sea