UDK: 574.5(282.249 Bunica) Research into the benthic diatoms in the Bunica River was performed during the period from 5th May 2013 to 9th January 2014 on three different sites, from the headwaters to the mouth. The Bunica River is located in the south-eastern part of the Mostar valley, in the south of Bosnia and Herzegovina. The aim of this research was to test the use of benthic diatoms as indicators and the use of diatom indices as a tool for estimating water quality in an example of a small karstic river. For that purpose, diatom indices were calculated using OMNIDIA GB 5.3 software. This was the first testing of diatom indices for a small karstic river. Diatom indices showed different results and huge variations between sites on the Bunica River. According to the results, the indices in the OMNIDIA software are not applicable for karstic rivers in Bosnia and Herzegovina and they must be modified for this purpose. This paper can be the first step towards calibration indices for karstic region. Also, it can be useful for the development of biomonitoring tool for karstic rivers in Bosnia and Herzegovina.

– The aims of this paper were to describe seasonal changes in the qualitative and quantitative composition of diatom taxa and the potential application of benthic diatoms for ecological status evaluation. Diatom indices (IPS and TI) were calculated from data from three different locations along a longitudinal profile of the Bunica, a small karstic river in Bosnia and Herzegovina. A total of 147 taxa were recorded in 12 samples. The most common taxa were Meridion circulare (Greville) C.Agardh and Ulnaria ulna (Nitzsch) Compère. Physical and chemical analyses showed low concentrations of nutrients, good oxygenation, typical pH for carbonate bed/origin and generally oligotrophic conditions and high ecological status. All sites had similar physico-chemical conditions and there were only few seasonal differences. Ordination of the diatom data showed that samples showed neither longitudinal nor seasonal patterns. Median value for IPS (16.8) and for TI (7.3) can be possible ‘‘expected’’ values for ecological status assessment for small karstic rivers in the Mediterranean region. We propose the use of the phytobenthos Intercalibration Common Metric (pICM - an index that combines the IPS and TI) as a national metric for countries developing WFD diatom methods at a late stage. One situation is described, and a solution, which is potentially transferable to other locations in Bosnia and Herzegovina and also to other countries facing similar challenges.

UDK: 556.115:574.587(282.249 Neretva) This paper presents the research results of benthos community (phytobenthos and macroinvertebrates) on three locations of the Neretva River: Glavatičevo, Žitomislići and Višići. According to typology of rivers, the site Glavatičevo belongs undertype 10a, while sites Žitomislići and Višići are undertype JIVT (heavily modified water bodies). Research of the benthos community has been done in December 2016 with the simultaneous monitoring chemical parameters of water. All research states showed a great number and a high diversity of benthic taxa, although sampling was spent in December. The saprobic values of benthos community at the site Glavatičevo indicates to oligosaprobic level, the water unloaded with organic substances. The site Žitomislići points to oligo/betamesosaprobic level, the water a bit loaded with organic substances. The site Višići according to phytobenthos demonstrates to oligo/betamesosaprobic level, while according to benthic macroinvertebrates point to betamesosaprobic level (the water loaded with organic substances). Based on saprobic values and chemical parameters of water in keeping with The decision on the characterization of the surface and underground water, reference conditions and parameters for the detection of water state and water monitoring (Official newspapers FBiH, No. 1/14), a maximum ecological potential has been registered on sites Žitomislići and Višići, while a high ecological status has been registered on the site Glavatičevo.

Soft‐mouth trout, Salmo obtusirostris has disappeared from most of its historical distribution range in the River Neretva catchment. Remnant groups are highly fragmented and distribution of the species is restricted to only 15% of it's historical area. The most abundant length range of remnant individuals is between 20 and 40 cm; with a significant decrease of the bigger individuals. Age population structure is dominated by younger fish aged 2, 3 and 4 years, however, age class 4⁺ and 6⁺ predominated in the lower river part. Specimens older than 8 years were not observed, and estimated fishing mortality (F) was high, particularly in the upper part of the river (0.786). The River Neretva soft‐mouth trout population is under heavy pressure including anthropogenic habitat changes and illegal fishery, leading to disappearance in number of formerly inhabited areas. The Upper and Lower Neretva are the only areas where the species is still abundant. However, the collapse of the number of old individuals increases the risk of extinction of the remaining wild subpopulations.