Concentrations of 17 elements in muscle, gills, liver and gonads of five economically important fish species from the Danube River

The Danube River in the vicinity of the city of Belgrade receives large amounts of untreated or poorly treated communal and industrial waste waters. The aim of this study was to assess elemental accumulation patterns in a number of economically important fish species in this area that belong to different trophic levels. Concentrations of 17 elements (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Se, Sr and Zn) were assessedin liver, muscle, gills and gonads of silver carp (Hypophthalmichthys molitrix), freshwater bream (Abramis brama), white bream (Blicca bjoerkna), common carp (Cyprinus carpio) and wels catfish (Silurus glanis) from the Danube River in Serbia by the use of ICP-OES. Silver carp specimens were differentiated from the other four species by high concentrations of Al and Fe in the liver. Common carp specimens were differentiated by high concentrations of Zn in gills, muscle and liver. Distribution of elements among different tissues had a consistent pattern among the species. Concentrations of Pb, Cd, As, Zn, Cu and Fe in muscle were at acceptable levels for human consumption, while concentrations of Fe and Zn were above maximum acceptable concentrations in liver and gonads

In vitro Radioprotective Activity of the Bryozoan Hyalinella punctata

The objective of the present study was in vitro evaluation of radioprotective activity of the freshwater bryozoan Hyalinella punctata on cultured human peripheral blood lymphocytes after irradiation with 2 gy of Co-60 gamma-rays. Since its water extract at concentration 0.001 mg/mL reduced the incidence of radiation-induced micronuclei for almost 30 %, it could be considered as a promising source of new natural products with the aforementined activity. Both the content of sulphur (1.17%) determined by gravimetric method and infrared absorption frequences (76 % similarity with those of bacitracin) of the investigated extract indicate the presence of organic sulphur compound(s) such as cyclic peptides and polypeptides which might be responsible for the observed radioprotectio

Assessing the range of newly established invasive species in rivers using probabilistic methods

Data on the presence of invasive species are often scarce, especially during the initial period following their introduction, when population abundance and species detectability are both still very low. In such cases, sporadic sightings in their newly occupied territory are often the only available information about their presence and distribution. Here, we demonstrate the potential of using probabilistic models for the assessment of the distribution of newly established invasive species in rivers, based on their sighting records. We have applied Solow's equation to the sighting record of the Amur sleeper (Perccottus glenii) in the Danube River, to assess the probable range of its population. The method applied indicated that, at the time when the sightings have been made (2003-2008), the Amur sleeper population in the Danube most probably extended between the 704.5 and 1,178.5 river km, while it was highly improbable (P lt 0.05) that it was present downstream from the 606 river km or upstream from the 1,277 river km. The application of this approach has, however, to be tested further on a larger number of scenarios and case studies in order to evaluate its reliability. What this method lacks in complexity, compared to more advanced species distribution assessments, it makes up by its ability to be easily used and quickly applied for preliminary assessments of the ranges of riverine species. As a result, the proposed approach might be of interest for scientists and managers dealing with invasive species

Diet and growth of asp, Aspius aspius (Linnaeus, 1758), in the Danube River near the confluence with the Sava River (Serbia)

P>A sample of 198 asp (Aspius aspius) was collected over a 28.5 km long section of the Danube River, upstream and downstream from the mouth of the Sava River, in order to provide information on population structure, diet, growth, and condition of this species. Total body lengths of sampled fish were 90-405 mm, and body weights 5-567 g. The sample was predominantly sub-adult fish aged 0+ to 4+ years. Sexually immature asp prevailed over the sexually mature asp. The sex ratio (1.4 : 1) was biased toward males. Male asps in the Danube become sexually mature only in their fifth year of life, and the females even later, as no sexually mature females were caught. The diet spectrum consists exclusively of fishes; of seven determined prey species, most important are bleak Alburnus alburnus, roach Rutilus rutilus, and goldfish Carassius auratus. Highest value of the seasonal vacuity index is in November (I(v) = 94.1), and the smallest in July (I(v) = 35.6). Trophic niche breadth is largest in May (H = 1.40), and smallest in November (H = 0.00). The largest average number of prey items is found in age class 4+ (2.33), the smallest in age class 0+ (1.00). Von Bertalanffy growth parameters are L(infinity) = 526.46, K = 0.28, and t(0) = 0.22. The length-weight relationship is described as log W = -5.16 + 3.03 log L. Fulton's condition factor increases with fish length, from 0.70 to 0.83. Regarding seasonal fluctuations, this factor begins to increase in late spring, with the trend continuing until autumn, and then decreasing from autumn to spring.Ministry of Science and Environmental Protection of the Republic of Serbia [143045

Diet and growth of asp, Aspius aspius (Linnaeus, 1758), in the Danube River near the confluence with the Sava River (Serbia)

P>A sample of 198 asp (Aspius aspius) was collected over a 28.5 km long section of the Danube River, upstream and downstream from the mouth of the Sava River, in order to provide information on population structure, diet, growth, and condition of this species. Total body lengths of sampled fish were 90-405 mm, and body weights 5-567 g. The sample was predominantly sub-adult fish aged 0+ to 4+ years. Sexually immature asp prevailed over the sexually mature asp. The sex ratio (1.4 : 1) was biased toward males. Male asps in the Danube become sexually mature only in their fifth year of life, and the females even later, as no sexually mature females were caught. The diet spectrum consists exclusively of fishes; of seven determined prey species, most important are bleak Alburnus alburnus, roach Rutilus rutilus, and goldfish Carassius auratus. Highest value of the seasonal vacuity index is in November (I(v) = 94.1), and the smallest in July (I(v) = 35.6). Trophic niche breadth is largest in May (H = 1.40), and smallest in November (H = 0.00). The largest average number of prey items is found in age class 4+ (2.33), the smallest in age class 0+ (1.00). Von Bertalanffy growth parameters are L(infinity) = 526.46, K = 0.28, and t(0) = 0.22. The length-weight relationship is described as log W = -5.16 + 3.03 log L. Fulton's condition factor increases with fish length, from 0.70 to 0.83. Regarding seasonal fluctuations, this factor begins to increase in late spring, with the trend continuing until autumn, and then decreasing from autumn to spring.Ministry of Science and Environmental Protection of the Republic of Serbia [143045

First record of a hybrid striped bass (Morone saxatilisxMorone chrysops) in the Danube River

Ministry of Education, Science and Technological Development of the Republic of Serbia [OI 173045, TR 37009

Distribution and accumulation of elements (As, Cu, Fe, Hg, Mn, and Zn) in tissues of fish species from different trophic levels in the Danube River at the confluence with the Sava River (Serbia)

Pikeperch (Sander lucioperca), European catfish (Silurus glanis), common carp (Cyprinus carpio), and gobies (Neogobius gymnotrachelus, Neogobius melanostomus) were collected from the Danube River (Belgrade section), and samples of liver, muscle, or whole-body composites (in the case of gobies) were analyzed for As, Cu, Fe, Hg, Mn, and Zn with inductively coupled plasma optical spectrometry to find out if there was a correlation between accumulation of these elements in predatory and prey species, as well as in pairs of species with overlapping diets. Concentrations of all analyzed elements were either higher (Cu, Fe, Mn, Zn) in liver than in muscle, or equal (As, Hg), except for Hg in carp, which was higher in muscle. Mercury concentration in liver and muscle of predators (catfish, pikeperch) was significantly ( lt 10(-4)) higher than in prey fishes (carp and gobies). The results indicate that Hg concentration was biomagnified through the food chain. Concentrations of As, Fe, and Hg in carp liver and gobies whole-body composite were similar, but carp had significantly ( lt 10(-4)) higher values of Zn and Cu in liver. The regression analysis and trendline equations indicate that the concentrations of all tested elements, except for As in liver, and Mn and Fe in muscle, were similar in predatory fish (pikeperch and catfish), on one hand, and in prey fish (carp and gobies), on the other hand. Distinctly high Zn concentration in carp is very common in this species due to its physiology. Concentrations of Hg and Zn were higher than the maximum acceptable concentration due to the high pollution level in this section of the Danube River, accordingly posing a risk for the human consumption of these fish species

First record of a hybrid striped bass (Morone saxatilisxMorone chrysops) in the Danube River

Ministry of Education, Science and Technological Development of the Republic of Serbia [OI 173045, TR 37009

Heavy metal and trace element bioaccumulation in target tissues of four edible fish species from the Danube River (Serbia)

Pikeperch (Sander lucioperca), European catfish (Silurus glanis), burbot (Lota Iota), and common carp (Cyprinus carpio) were collected from the Danube River (Belgrade section, Serbia), and samples of liver, muscle, and gills were analyzed for Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Se, Sr, and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES) to highlight the importance of species and tissue selection in monitoring research, contaminant studies, and human health research. The Kruskal-Wallis test revealed significant differences between fish species in regard to metal levels in liver, muscle, and gills. The principal component analysis (PCA) indicated that the studied fish species could be grouped on the basis of the level of analyzed elements in liver and gills. The Mann-Whitney test showed two subsets (one comprising two piscivorous species, pikeperch and catfish, and the other, two polyphagous species, burbot and carp) in regard to Cr and Hg levels in liver (higher levels in piscivorous species), as well as B, Fe, and Hg in gills (B and Fe with higher levels in polyphagous and Hg in piscivorous species), and As in muscle (higher levels in polyphagous species). Carp had distinctly higher levels of Cd, Cu, and Zn in liver in comparison to other three species. None of the elements exceeded the maximum acceptable concentrations (MAC). However, since Hg levels are close to the prescribed MAC levels, the consumption of these fishes can be potentially hazardous for humans