Macroinvertebrates of Serbian streams and their significance as bioindicators in estimation of water quality

Despite the fact that it represents only a small part of the total amount of water on the planet (1.2%), land-based water is very significant for man. The demographic explosion that marked the 20th century on the one hand caused constant growth of the need for pure water and on the other hand increased the extent of water pollution due to development of industry, intensification of agriculture and expansion of urban regions. Human action leads to greater or lesser changes of ecological factors in aquatic ecosystems (amount of dissolved oxygen, pH, heavy metal concentration, etc.), regulation of watercourses, disruption of communication between biocoenoses and disturbance of the natural water regime (through the creation of reservoirs). All of this brings about changes in biocoenoses that can be very pronounced, going even so far as to the virtual destruction of life in an aquatic ecosystem or in less severe cases to replacement of an existing biocoenosis by a new one that due to greater homogeneity of ecological factors is characterized by lower diversity. In order to conserve the water resources of the Republic of Serbia, it is necessary to monitor them closely. Biomonitoring is an obligatory part of this task because it is a simple, fast and economical way to follow the state of ecosystems of land-based water. Of all groups of aquatic organisms used in biomonitoring: bacteria, protozoans, zooplankton, phytobenthos, macrophytes and fish, macroinvertebrates are the most widely employed, especially in streams, where they are absolutely the most significant community of bioindicatory organisms. Modern biomonitoring of streams both in the world at large and in Serbia is based to the greatest extent on the use of macroinvertebrates as bioindicators of water quality owing to their many advantages over other aquatic organisms. Macroinvertebrates are widely disseminated organisms that inhabit various types of aquatic ecosystems, from little temporary (ephemeral) stagnant pools, small springs and creeks to large lakes and rivers. The great diversity of macrozoobenthic organisms and extremely complex structure of their communities on the one hand make them very sensitive to anthropogenic action causing changes of ecological factors, and on the other hand enable them potentially to respond with changes in the composition of their biocoenoses that are proportional to intensity of the anthropogenic action in question. Such organisms are characterized by the ability to persist in conditions of fast flowing water because they live attached to the bottom, possess long life cycles and have limited mobility. Their low mobility and sedentary way of life enable the investigator to establish the state of ecological factors on a given area. The relatively long life cycles (lasting 2-3 years) of these organisms make it possible to investigate changes occurring over the course of time. Apart from biological considerations, there are also numerous practical reasons why these organisms are considered good indicators of water quality: samples are taken with relatively inexpensive equipment; the taxonomy of most groups has been thoroughly elaborated; keys for their identification are available; methods that employ macrozoobenthic organisms have been used for many years and are highly reliable; and the responses of certain organisms to different types and levels of pollution have been precisely defined. Macrozoobenthic organisms can be used to test the influence of anthropogenic stress on aquatic. biotopes at all levels of biological organization, from molecular to ecosystematic. The effects of pollution on these organisms under natural conditions are most often analysed on the level of their populations or communities, using structural attributes (measured by indexes of diversity and similarity, biotic indexes, etc.) or functional characteristics, including, for example, primary production, respiratory processes, biomass (secondary production) and circulation of elements, but also aspects of the organisms' life history such as functional guilds in the feeding of a taxon. Investigation of macrozoobenthic communities has been and will be a central part of the ecology of land-based water, partly due to the fact that streams for them represent a crucial link between resources in the form of organic matter (for example, fallen leaves, algae, detritus, etc.) and fish in food webs, and partly due to the diversity and wide dissemination of the organisms involved. In view of these facts, it is unsurprising that systematic research on the fauna of macroinvertebrates in land-based water of Serbia was initiated almost a century ago and has been carried out in continuity with varying intensity up to the present day. More intensive use of macroinvertebrates in biomonitoring of the ecosystems of land-based water in Serbia, as in the world at large, began around the middle of the last century, at which time they started to be included in monitoring of water quality by the Hydrometeorological Institute of Serbia. As can be seen from the above, Serbian science actively followed world trends in biomonitoring of land-based water from the very start, although the intensity of these investigations was highly variable. Intensification of research on macroinvertebrates and their use in biomonitoring of land-based water occurred during the 1990s, with the formation in Novi Sad, Belgrade and Kragujevac of several independent teams of investigators that laid a solid foundation for further progress, as is evident in a series of studies introducing new and modern methods of biomonitoring, methods such as employment of biomarkers, recording of morphological asymmetries and deformities and use of artificial neuron networks. To be specific, the work of these teams has greatly advanced available knowledge about biology of the macroinvertebrates of land-based water in Serbia and continued to keep pace with world trends in their use for biomonitoring. A good example is the development of BNBI and incorporation of a number of EU standard methods into norms for regulation of biomonitoring in Serbia. Despite this positive trend, it must be stated that the use of macroinvertebrates as bioindicators of the quality of land-based water in Serbia is relatively limited because in the majority of cases it is done within the framework of saprobiological analyses, whereas biotic indexes are for the most part unjustifiably ignored, while multimetric indexes and the multivariant approach have not even begun to be employed. For these reasons, the state of biomomitoring in Serbia still cannot be considered satisfactory. To be specific, if the extent of land-based water biomonitoring in Great Britain where it is continuously conducted at more than 6000 localities is compared with the state of affairs in Serbia where about 90 localities out of a planned 500 are continuously monitored it can be seen that the level of biomonitoring in our country is disproportionally lower. Moreover, a comparison of stream quality in Great Britain, despite that country's significantly more advanced industrial development and greater population density, with the situation in Serbia shows that the quality of streams in our country is conspicuously far worse. It is clearly necessary to expand the volume and content of biomonitoring because only in that way will it be possible to make correct decisions in the management of water resources and thereby improve their quality. Meanwhile, at the existing level of macroinvertebrate studies in Serbia, that is not simply a question of political willingness, but also a task limited by the quality and quantity of fundamental research. As has been stated before, successful use of macroinvertebrates in biomonitoring demands an exceptionally good knowledge of the base reference state. That at the present time calls for additional faunistic, taxonomic, biogeographic and toxicological research, as well as studies on the typization of watercourses. It will be possible to define groups of reference localities in Serbia, as has been done in Great Britain, only if the inventory of species in our country is known in detail, if taxonomic problems are resolved, if keys for the identification of species are available, if their range has been clarified and if the types of watercourses and their ecological status (condition) are known. This in turn will make it possible to apply some highly organized system of biomonitoring like RIVPACS or to develop a multimetric index like the ones elaborated in the EU's AQEM program. That the path to this goal is long is clearly indicated by the fact although acknowledged experts today exist for the taxonomy of macroinvertebrate groups such as Chironomidae, Oligochaeta, Heteroptera, Trichoptera, Amphipoda and Gastropoda, research on a number of very important groups such as Ephemeroptera and Plecoptera has only just begun, a situation that has a significant effect on the quality and reliability of determination of these groups, knowledge about their distribution and awareness of their ecological preferences, as well as on the typization of land-based water habitats in Serbia vis-a-vis other countries in the world. Progress in this area largely depends on politics of the state, that is on the measure in which it is ready to support studies, finance the necessary increase in the number of researchers and through selection of programs and projects guide investigative efforts in an appropriate direction. It is also necessary to widen the network of localities at which sampling is prescribed by law, since only by sampling in an organized and planned manner will it be possible to collect an adequate number of data in a procedurally uniform way permitting the drawing of comparisons, development of new biomononitoring methods in Serbia and improvement of ones already in existence. That is the only way to form a standardized database of information about the ecosystems of Serbian streams. Such a database will be the foundation needed for the standardization of reference localities, which represents a key step toward the implementation of both multivariant and multimetric methods in biomonitoring

Comparative body shape variation of the European grayling Thymallus thymallus (Actinopterygii, Salmonidae) from wild populations and hatcheries

We employed geometric morphometric techniques to investigate external (body) morphology of European grayling (Thymallus thymallus) populations from the wild and hatchery facilities. Wild graylings were representative of Balkan and Caspian phylogenetic clades, whereas hatchery-reared specimens originated from Balkan and Adriatic phylogenetic clades. Individuals of T. thymallus from the Adriatic phylogenetic clade were the largest, followed by those from the Balkan phylogenetic clade, while graylings from the Caspian phylogenetic clade were the smallest. Graylings from hatchery facilities were larger than graylings from the wild. Body shape variation in T. thymallus coincides with genetic differentiation of the analyzed populations, whereas it is less influenced by difference in environment they experience in wild and captive habitats. Although hatcheries can generate large numbers of individuals, some of which will have an extreme phenotype, the variance in body shape was similar in captive and wild populations. Allometric relations were different between specimens from the wild and from hatchery facilities, as well as among those belonging to different phylogenetic clades. Allometric analyses performed separately for the wild and hatchery-reared populations revealed significant effect of allometry and similar trends in size-related shape variation among populations from different phylogenetic clades. We found that phenetic relationships among the studied wild grayling populations inferred from non-allometric body shape variation better reflected their phylogenetic relationships than equivalent data from hatchery populations

Risks from the microbiological and chemical contamination of fish materials

Fish is today one of the most important commercial material. In our market as in the world market they are present in fresh and manufactured products. Fish products always have some risk. They could be contaminated with dangerous chemicals and biological contaminants. From biological originated polutions Aflatoxin and other Mycotoxins are very dangerous. The contamination starts in fish ponds, in canals and swamps. Also, the contamination occurs at storage and prepararation of fish materials. It is very important to recognize hygienically correct fish material and control fish food and different products from fish by educated inspectors (Vlahović, 1999)

Exploring the phylogenetic signal in the cranial variation of European populations of grayling (Actinopterygii, Salmonidae)

This is a preliminary and exploratory study of cranial variation in European populations of grayling. We investigated the correspondence between size/shape variation of the dorsal (DC), ventral (VC) and occipital (OC) cranium and phylogenetic relationships (inferred from mitochondrial control region – mtDNA CR and microsatellite DNA data) of six grayling populations: three from Balkan phylogenetic clade and two from Caspian phylogenetic clade of the European grayling Thymallus thymallus and one population of the Adriatic grayling Thymallus aeliani, which until recently was considered the Adriatic phylogenetic clade of T. thymallus. Significant size and shape differences were found between populations in all three cranial views. However, significant size-related shape variation (allometry) was found for DC and VC, but not for OC. The size variation of each cranial view does not contain phylogenetic signal, but size variation of OC is consistent with genetic variation inferred from microsatellite DNA. Regarding shape variation, a significant phylogenetic signal was detected only for OC, and only the shape variation of OC is consistent with the genetic variation inferred from the mtDNA CR. Moreover, the Adriatic grayling T. aeliani (Soča population) was clearly separated from the three T. thymallus populations of the Balkan phylogenetic clade and the two T. thymallus populations of the Caspian phylogenetic clade only at the level of OC. Thus, our results suggest that different cranial regions differ in allometry, reflect phylo(genetic) relationships differently, and exhibit differences in ecophenotypic plasticity, with OC seeming best suited to represent the phylogenetic relationships of the grayling populations studied

The begginings of Pistia stratiotes (Linnaeus, 1753) invasion in the lower Danube delta: The first record for the Province of Vojvodina (Serbia)

Pistia stratiotes L. (water lettuce) is known as one of the most troublesome aquatic macrophytes, strongly affecting the environment and human activities in slowmoving and stagnant inland water systems. It was introduced into Europe in the 20th century and has since spread to 15 European countries. This paper presents data on the first record of this invasive aquatic plant in natural inland waters of Vojvodina (northern lowland part of Serbia) and discusses the possible pathways of its introduction. Field research was conducted in October and November 2017 on the Begej River in Vojvodina Province (Serbia), where populations of P. stratiotes were documented for the first time near Srpski Itebej, in close proximity (1.2 km downstream) of the Romanian border. The plant samples were collected, photographed in situ and deposited in the BUNS Herbarium. The relevant environmental data were also recorded in situ and water samples were collected for chemical analysis. This new record presents the first documented case of this invasive alien in rivers in Serbia, and expands upon the previous findings of this species in natural thermal waters of south-eastern and eastern Serbia. Taking into account the distance from the Romanian border and the fact that it has already been present in this country for several years, this introduction could be attributed to the spontaneous spreading of P. stratiotes from this neighbouring country. Nevertheless, despite this possibility, discarded aquarium plants cannot be entirely discounted as a potential source of this new introduction. Although it is hard to predict the exact consequences of this new introduction at such an early stage, bearing in mind the detrimental impacts P. stratiotes can have on the environment and excellent lateral connectivity of the Begej River with the canal and river network of Serbia, this finding highlights the need to take urgent action to control and instate regular monitoring measures, especially on the rivers and canals located close to the state borders