Goran Marković

Non-native and translocated fish species in Serbia and their impact on the native ichthyofauna

A total of 22 fish species have been introduced into the inland waters of Serbia, either intentionally or accidentally. This paper provides a summary of data concerning time and reason of introduction, mode of expansion, degree of acclimatization, impact on native fish and estimated area of recent distribution. Four of the non-native fish species currently occupy more than 51% of Serbian territory while 5 of them occupy between 21–50% of territory. This paper reviews impacts of introduced freshwater fish in Serbia based on collected data.

Application of the MODIPROM method to the final solution of logistics centre location

AbstractAwareness of the role of logistics centres is the precondition for successful planning, optimization, design, management, control and analysis of logistics processes and subsystems. Transportation requirements in supply chains, ecological requirements and the need for quality life in cities particularly emphasize the importance of selection of logistics centre locations, manner and time of supply. Taking into account the significance of selection and ranking of different locations, it is necessary to compare, as objectively as possible, the influences of various criteria and reduce them to a common function, i.e. present the methodology of solving complex problems associated with ranking of alternatives. The proposed method is expected to be a comprehensive tool of decision makers during the selection of the optimal logistics centre locations.

The role of allochthonous (non-native) fish species in Serbian aquaculture

Fish farming is the only type of aquaculture in Serbia. Fish farming is mostly carried out in cyprinid and salmonid (trout) fishponds (over 95% of the total fish produced), with considerably lower ichthyoproduction being practiced in cages and some bodies of open water such as reservoirs and channels. Serbian aquaculture currently includes 12 fish species, 4 of which are allochthonous (non-native). With the exception of the rainbow trout (Oncorhynchus mykiss) and, to a certain extent, grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis), allochthonous fish species have no economic importance. The presence and abundance of certain allochthonous species in fishponds and open waters have a negative effect on the total ichthyoproduction.

A contribution to the data on tench (Tinca tinca L., Cyprinidae, pisces) distribution in Serbia

The studies on the ichthyofauna of Serbia that have been conducted so far indicate the sporadic tench (Tinca tinca L.) presence in typical habitats. The hydroenvironmental conditions necessary for the survival of this fish species are highly variable and, generally, are more favourable in the northern part of the country (the Vojvodina Province). Although the tench presence has been registered at over 30 sites, there is a tendency of a decrease in population abundance. This is due to the reduction of the surface area of the macrophyte-covered flood zones induced by the damming and regulation of rivers, high water level fluctuations, and water amount reduction in the majority of watercourses, a massive increase in the number of allochthonous phytofagous species, reservoir sediment deposition, water quality deterioration and other factors. The tench conservation status in Serbia is officially designated as Low Risk - Least Concern. It may be transferred to a higher category if the tendency towards deterioration of survival conditions for the species should continue.

Alternative Cereals in Carp (Cyprinus carpio L.) Nutrition

Summary Due to their high carbohydrate content, cereals are the main source of energy in human, livestock and fish diets, with wheat and maize being the most commonly used crops. Although these two crops, along with rice, satisfy about 50% of human energy requirements, it is necessary to introduce other crops, which are of minor commercial importance. This necessity has been intensified by the growing needs of aquaculture, particularly with respect to carbohydrate requirements. Cereal grains account for an average of 35-45% of the feed ration for common carp (Cyprinus carpio). Experiments have been conducted on the use of barley, triticale and rye as substitutes for wheat and maize. The grains of these replacement cereals are preliminarily subjected to gelatinisation due to the high content of crude starch. Results indicate the possibility of partial or complete substitution (for maize) in some fish feeds. The usability (feed value) of cereals in fish nutrition is ranked in the order: wheat > triticale > maize > barley > rye.

First record of water chestnut (Trapa natans L., Trapaceae, Myrtales) in Central Serbia.

Water chestnut (Trapa natans L.) is a floating macrophyte that generates differing views on its role and importance in aquatic ecosystems. It is protected as a rare species in a number of European countries and is an invasive species in some regions of the world. T. natans inhabits stagnant and slow flowing waters that exhibit large fluctuations in water level. Occurrence records are frequently reported from the north of the Republic of Serbia (Vojvodina Province), while there are no relevant data about its habitats in southern parts of the country. The first record of T. natans in Central Serbia was from the Međuvrsje Reservoir on the Zapadna Morava River (the Danube River Basin) in 2011. A marked increase in species abundance in certain sections of the reservoir was observed in 2012. High water temperatures and continuous inflow of nutrients reported in recent years will most likely induce further propagation of this species, potentially leading to further eutrophication of the system and upsetting the ecological balance of the new habitat.