Marina Piria

Evaluation of Genotoxic Pressure along the Sava River.

In this study we have performed a comprehensive genotoxicological survey along the 900 rkm of the Sava River. In total, 12 sites were chosen in compliance with the goals of GLOBAQUA project dealing with the effects of multiple stressors on biodiversity and functioning of aquatic ecosystems. The genotoxic potential was assessed using a complex battery of bioassays performed in prokaryotes and aquatic eukaryotes (freshwater fish). Battery comprised evaluation of mutagenicity by SOS/umuC test in Salmonella typhimurium TA1535/pSK1002. The level of DNA damage as a biomarker of exposure (comet assay) and biomarker of effect (micronucleus assay) and the level of oxidative stress as well (Fpg—modified comet assay) was studied in blood cells of bleak and spirlin (Alburnus alburnus/Alburnoides bipunctatus respectively). Result indicated differential sensitivity of applied bioassays in detection of genotoxic pressure. The standard and Fpg—modified comet assay showed higher potential in differentiation of the sites based on genotoxic potential in comparison with micronucleus assay and SOS/umuC test. Our data represent snapshot of the current status of the river which indicates the presence of genotoxic potential along the river which can be traced to the deterioration of quality of the Sava River by communal and industrial wastewaters. The major highlight of the study is that we have provided complex set of data obtained from a single source (homogeneity of analyses for all samples).

Ichthyofauna of the River Sava System

On the survey of the recent records, the fish and lamprey fauna of the River Sava catchment consists of 74 species, 15 of which being considered alien. The indigenous species diversity, explained using the relation N = 0. 546 A 0.232, fits well into the range common for large catchments in Europe. Both taxonomic and ecological diversity, as well as the character of fish communities in streams and rivers, are strongly correlated with the stream order. On the relative abundance of species in fish communities, the upper rhithron fish communities cluster distinctly from those belonging to the middle rhithron, within which several subgroups of fish communities were distinguishable. Fish communities of the middle rhithron character in streams and small rivers stand distinctly apart from those belonging to particular sections of large rivers (e.g., the Rivers Sava, Drina, Vrbas, and Bosna), with the transitional type of middle rhithron fish community in larger rivers (e.g., those in the Rivers Una and Sana) that resemble more to the fish communities common in middle rhithron streams. Fish communities in the middle section of the River Sava in Croatia and in the bordering area with Bosnia and Herzegovina mainly belong to the lower rhithron, attaining the character of potamon in the most downstream, Serbian section. River Sava’s fish communities strongly interact with the ones occurring in the most downstream sections of their largest tributaries, e.g., the Rivers Una, Vrbas, Bosna, Drina, and Kolubara, which makes them very similar in structure in the areas of river mouths. Classification of fish communities based solely on the presence and absence of species revealed similar general pattern of fish community classification, though with the more sharp delimitation between those belonging to the upper and middle rhithron on one and to the lower rhithron and potamon on the other side. That was supported by the determination of fish communities belonging to the upper rhithron with brown trout Salmo cf. trutta, European bullhead Cottus gobio, and minnow Phoxinus phoxinus as the most common fish species. Fish communities belonging to the middle rhithron were determined mainly with chub Squalius cephalus and spirlin Alburnoides bipunctatus, whereas brook barbel Barbus balcanicus and stone loach Barbatula barbatula occurred in both upper rhithron and middle rhithron. Nase Chondrostoma nasus were associated with both middle and lower rhithron fish communities. The most common fish species that determine the lower rhithron fish communities were common bream Abramis brama, ide Idus idus, and bleak Alburnus alburnus, with the northern pike Esox lucius, Balon’s ruffe Gymnocephalus baloni, and racer goby Neogobius gymnotrachelus as significant species explaining fish communities of both lower rhithron and potamon. The level of production of fish in the River Sava varies remarkably within the sections with the similar ecological features, as well as between the sections that differ for the type of fish community. The greatest biomass and annual natural production were recorded in the sections homing the potamon and lower rhithron fish communities, especially in the flooding areas of side arms and oxbows which serve as spawning areas and nurseries. A total of 15 alien fish species was recorded in the River Sava catchment, the Prussian carp Carassius gibelio and brown bullhead Ameiurus nebulosus being assessed the most invasive in the areas with the potamon fish community. A strong impact from both long-term and recent stocking with alien hatchery-reared brown trout strains and rainbow trout in the upper rhithron fish communities was recently recognized. Mudminnow Umbra krameri and huchen (or Danube salmon) Hucho hucho are considered the two most threatened fish species of the River Sava catchment, where various types of riverbed modifications, especially the damming, were seen the most prominent threatening factors for fish diversity.

Characterization of sections of the Sava River based on fish community structure.

Sampling was undertaken, with the same fishing gear and along the Sava River, from its source to its confluence, in September 2014 and September 2015. In total, 44 fish species were identified, of which 37 were native species and 7 were alien. Fish samples revealed independence in terms of both species composition and their abundance under different hydrological conditions. During flooding and high water levels in 2014, pelagic fish species were sampled in greater proportion than at lower water levels in 2015 when benthic fish species were more abundant. The flood wave in 2014 was accompanied by catch of common carp, Cyprinus carpio, a typical lower rhithron fish species in the upper course, and of tench, Tinca tinca, a typical potamon fish species of backwaters, in the main channel of the lower Sava River. One specimen of bighead goby, Ponticola kessleri, which is common in the potamon fish community, was caught during the 2015 sampling close to the boundary between the upper and middle sections of the Sava. This is the first record of Ponto-Caspian gobies in the inland waters of Slovenia. Its finding far upstream indicates a strong effect of an as yet unidentified stress along the Sava River up to the spot where the bighead goby was sampled. Finally, these results indicate that pelagic fish species are more resistant to the stressful effect of flooding than benthic species, and that the structure of fish communities is influenced/affected by flooding as a short-term stressor. The progressively increasing number of alien fish species downstream in the Sava River point to the effects of long-term human-induced stressors in the area.

Past and present of and perspectives for the Danube huchen, Hucho hucho (L.), in the Danube basin

Abstract Huchen, Hucho hucho (L.), also known as Danube salmon, is an iconic, endemic species inhabiting the Danube basin of Central Europe. Historically, the Danube huchen inhabited a significant portion of the Danube drainage basin stretching to the Iron Gate and the majority of large and medium-sized tributaries. Larger populations in the natural zoogeographical distribution of Danube huchen were once found in Austria, Bavaria, the former Yugoslavia, Slovakia, and western Ukraine. Currently, the species is severely fragmented within the Danube drainage, where most populations exclusively depend on stocking and natural reproduction is very limited due to habitat alterations and flow regime changes. In the Czech Republic and Poland, Danube huchen occurrence is the result of introducing the species to several rivers in the Baltic Sea and North Sea drainage basins. Danube huchen is a threatened species throughout is range of occurrence, and, according to IUCN criteria, it is classified as endangered (EN). Habitat degradation is the most serious negative factor impacting huchen populations. Dam construction, pollution, and river regulation have led to loss and degradation of spawning sites. Detailed research on population abundance and structure is greatly needed to help identify the populations which are most threatened and to help to develop the best protection systems.

The game damages on agricultural crops in Croatia

Conflicts between wildlife and humans have been reported from all over the world, but in Croatia the extent and intensity of the conflict is increasing. Agricultural damage by game is a major concern for both agricultural and wildlife agencies at the national level. In this study 4,695 cases of game damage over a 4-year period were analysed. Results indicated that the total amount of economic impact on agriculture from game damage was significant. The distribution of payments shows that a majority of payments have lower economic value with an average amount of single payment being 477.08 €. The annual number of payments was found to have a negative correlation coefficient (-0.469) to the total payment amount for damages. According to the number of payments (68% of the number of payments) and the payment amount (60% of total payment amount), the crop most often damaged was maize. Analysis of the data found that there was a negative growth trend of payment frequency and total payment amount for grape vineyards. The correlation between yearly number of payments and yearly production was not calculated for any crop. The high seasonal nature of payments was a determent of seasonal regression using a dummy variable regression (r2=0.93). A comparison of the monthly number of payments and monthly amounts is depicted by a time series using a seasonal line. The impact of wild boar damage on agriculture crops, in total, leads to the conclusion that this game species is a major problem. The results showed a specific subset of game damage in Croatia and, as such, it can be extrapolated to provide insight into the damage caused by wild boar in other countries.

Dietary items as possible sources of 137Cs in large carnivores in the Gorski Kotar forest ecosystem, Western Croatia

The mountain forest ecosystem of Gorski Kotar is distant from any significant sources of environmental pollution, though recent findings have revealed that this region is among the most intense (137)Cs contaminated area in Croatia. Therefore, the aim of this study was to investigate (137)Cs and (40)K load in three large predator species in the mountain forest ecosystem. Radionuclides mass activities were determined by the gamma-spectrometric method in the muscle tissue of brown bear (47), wolf (7), lynx (1) and golden jackal (2). The highest (137)Cs mass activity was found in lynx (153 Bq kg(-1)), followed by brown bear (132 Bq kg(-1)), wolf (22.2 Bq kg(-1)), and golden jackal (2.48 Bq kg(-1)). Analysis of 63 samples of dietary items suggests that they are not all potentially dominant sources of (137)Cs for wildlife. The most important source of radionuclides for the higher parts of the food-chain from the study area were found to be the mushroom species wood hedgehog (Hydnum repandum), with a transfer factor TF of 5.166, and blueberry (Vaccinium myrtillus) as a plant species (TF=2.096). Food items of animal origin indicated higher mass activity of radionuclides and therefore are possible moderate bioindicators of environmental pollution. The results also revealed that possible unknown wild animal food sources are a caesium source in the study region, and further study is required to illuminate this issue.

Biochemical indicators and biomarkers in chub (Squalius cephalus L.) from the Sava River

Biochemical indicators and biomarkers were analyzed in the liver and gills of chub caught in three localities along the Sava River exposed to different environmental impacts. Sampling sites were: downstream from Zagreb (Zgd), downstream Sremska Mitrovica (SM) and downstream from Belgrade (Bgd). We observed that the relative amounts and levels of activity of Cu, Zn containing superoxide dismutase and glutathione in both the liver and gills, and the relative amounts of heat shock protein (HSP90) and metallothioneins in the gills were highest in the Zgd locality, suggesting a higher impact of metal pollution. The Zgd locality had higher concentrations of trace metals in the water, especially iron. In the SM and Bgd localities, higher relative levels of glutathione peroxidase and catalase were recorded (especially in SM) as compared to the Zgd locality, pointing to the presence of hydrogen peroxide and different classes of organic peroxides. Low water oxygen and high temperature levels in the Bgd locality suggesting different metabolic activity between examined locations. Our results suggest that different presence and concentrations of individual environmental factors (total environment) influence the way how fish establish homeostasis.

Variation of wild boar reproductive performance in different habitat types : implications for management

The aim of this study was analyze reproductive performance of wild boar in different habitat over a 7-year period (2006–2012). A total of 468 pregnant females and 2.819 fetuses were analyzed, the mean number of fetuses was 6.02 (median = 6) per animal (4.62 per juvenile, 6.39 per yearling and 6.77 per adult). In litters, male-biased fetuses occurred significantly more often than female, the overall fetal sex ratio is 1: 0.86. Positive reproductive traits increased up to 90 kg of live body weight and then decreased. The reproductive parameters observed in our study reflect a relatively high reproductive capacity compared to the populations in southern and northern Europe, but are comparable with some populations in central Europe. Concerning habitat conditions, it is obvious that they influence the reproductive performance of females, and therefore must be included in management plans.

A review of introduction of common carp Cyprinus carpio in Pakistan: origin, purpose, impact and management

Abstract Common carp Cyprinus carpio was introduced from Thailand to Pakistan in 1964 for the purpose of aquaculture. Due to its high tolerance to temperature and turbidity, and prolific pond breeding habit, it was established promptly in most of natural inland waters, including rivers, lakes, streams, canals, wetlands and even village ponds of the country. Although common carp became one of the most abundant cyprinid species in inland waters and important food fish in Pakistan, its impact is not well documented. Fish farming of common carp has been carried out in Pakistan since 1970; initially it grew slowly but now it is playing an important role in the economy of the country by employing more than 400,000 people. Nowadays, farming of freshwater carps is present throughout Pakistan, especially in the provinces of Punjab and Sindh. There is a huge potential in common carp farming and it could help increase the livelihood of people and gross domestic product (GDP) of the country as well. Still, there is a need to improve the fish farming practice to meet the world-class demands that could only be possible by the keen interest of policy makers and stake holders with better management.

First record of palmetto bass (Morone saxatilis x M. chrysops) in the Croatian part of the river Danube

On October 19, 2010, a male specimen of palmetto bass (Morone saxatilis x M. chrysops) was caught by commer- cial fishing net in the Croatian section of the river Danube (302 mm TL and 331 g). It was in its third year of age (2+). A condition factor of 1.20 was based on the total length. Six specimens of prey fish were found in its gut (22.97 g altogether). Morphometric and meristic traits of this palmetto bass are presented and its possible threat to the fish community is dis- cussed.