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Inter-population variability in morphological traits and fecundity of Alburnus alburnus (Linnaeus, 1758) from Bosnia and Herzegovina was analysed in this study. The results of the analyses based on 21 standard measurements and six meristic characters have shown the highest variation between distance between pelvic (ventral) fins and anal aperture. Analysis of variance (ANOVA) indicate statistically significant differences between six populations. Differences among meristic characters have been tested by Multiple Comparisons Kruskal-Wallas. Obtained results indicate statistically significant difference among samples for number of branched rays for caudal fin (KA/Ca), lateral line scales (Le) and a number of gill rackers (Rac). Discriminant function analysis indicate characters that had the strongest effect on the geographical variation between A. alburnus samples from Bosnia and Herzegovina. Characters with the strongest discriminant power are: preanal distance, length of pectoral fin, length of the ventral (pelvic) fin, minimum body height, caudal fins branched rays, and pelvic fins branched rays.Values for weight of the gonads and gonadosomatic index (GSI) have not shown any statistically significant difference among observed bleak populations. Regression analysis has been used to estimate the relations between GSI and standard length, body, and gonads weight. The gonadosomatic index has shown positive, non substational, relationship to gonads weight.

AbstractBuško Blato Reservoir, the third largest hydro accumulation in Europe, is situated in the south-eastern part of the karstic Livanjsko Polje Valley. This aquatic ecosystem is distinguished by a very rich ichthyofauna and the presence of four endemic fish species. Numerous studies focus on ichthyological researches of Buško Blato Reservoir. Its ichthyofauna has been exposed to changes in ecological factors, which in turn reflected on the structure and composition of fish populations. The main objective of this paper was to assess the current state and predict future trends in the ichthyofauna structure and dynamics based on the field data and comprehensive analyses of literature data. The results of the research indicated the presence of 11 fish species from four families, which is the largest number of fish species ever recorded in this ecosystem. Sander lucioperca, Lepomis gibbosus, Pseudorasbora parva and Tinca tinca were recorded for the first time in this ecosystem, while some previously recorded species were not found. The results of the analyses clearly indicate the presence of natural interspecific competition and significant level of threats to the endemic fish species caused by human activities.

UDK 574.587:595.371(497.6 Sarajevo)          595.371:502.17(497.6 Sarajevo) The paper is the result of a research into the composition of benthos of the hydro-system within the protected area of Vrelo Bosne (water source of River Bosna) and the wider region during 2009 - 2010 period. The aim of the paper is to establish the state of the populations of the endemic species of amphipod Niphargus illidzensis S., get an overview of the underlying ecological conditions within the habitats, conduct a morpho-metrical analysis of the specimens and designate the new habitats of this species. By analysing the basic physical/chemical and biological (phytobenthos and macrozoobenthos) parameters a high-quality level of water inside the habitats of this endemic species of amphipods was established: the water source of River Bosna (four), stream Stojčevac and the water source in the area of Blažuj. The highest number of specimen was recorded in stream Stojčevac where the longest specimen was also noted – 22 mm. The source in the area of Blažuj (potable water bottling plant Dijamant) is the new habitat for this species which was previously only noted in the area of Avala and Topčider near Belgrade. The paper presents a comprehensive overview of the ecology and the current state of this endemic species after its repeated description dating from 1974.