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Since ticks have been recognized as one of the most important vectors of pathogens causing serious diseases in humans, a number of studies have focused on identifying the pathogen composition as well as transmission and infection mechanisms. Although a plethora of detection methods is available today, PCR-based approach is regarded as the most sensitive and rapid. However, common challenges in molecular analyses conducted on ticks are weak amplification results because of present inhibitors, either from a mammalian bloodmeal or a male DNA in female reproductive organs. Present study aimed to evaluate which body part of an engorged tick is the most preferable as a starting material in DNA extraction for molecular detection of Borrelia burgdorferi sensu lato, causative agent of Lyme borreliosis. We analyzed 58 Ixodes ricinus ticks removed from patients in The Center for Emergency Medical Assistance of the Sarajevo Canton, Bosnia and Herzegovina. Our findings suggest using the anterior half of semi-engorged and fully-engorged ticks for DNA extraction with the purpose of Borrelia detection.

Interspecijska hibridizacija u porodici Cyprinidae zabilježena je širom svijeta, a Abramis brama (deverika) i Rutilus rutilus (bodorka) su jedan od često prijavljenih hibridizirajućih parova. Jedini opis takvog događaja u Bosni i Hercegovini potiče iz akumulacije Modrac. Koristeći morfološke i molekularne markere, istražili smo prisutnost hibrida, odredili smjer hibridizacije i procijenili strukturu hibridnih skupina u ovom ekosustavu. Naša su otkrića potvrdila nesmetanu prirodnu hibridizaciju bodorke i deverike u akumulaciji Modrac. Primjenom NewHybrids softvera, preko 50% hibridnih primjeraka klasificirano je kao F2 hibridi, dok su ostali kategorizirani kao čisti roditeljski oblik, što je prvi takav nalaz u Europi. Analiza mitohondrijskog citokroma b pokazala je da 90% hibridnih jedinki ima majčinsko podrijetlo od deverike. Hibridna skupina izrazila je veće srednje vrijednosti promatrane heterozigotnosti i raznolikosti gena u odnosu na obje roditeljske vrste. Otkriveni su znakovi introgresivne hibridizacije između roditeljskih vrsta. Čini se da hibridna zona akumulacije Modrac slijedi intermedijarni ili "ravni" hibridni model zasnovan na uravnoteženoj raspodjeli roditeljskih i hibridnih genotipova. Potrebna su daljnja istraživanja kako bi se rasvijetlili čimbenici koji omogućuju preživljavanje i uspjeh u parenju jedinki poslije F1 generacije., Interspecific hybridization in the Cyprinidae family has been recorded worldwide, with Abramis brama (bream) and Rutilus rutilus (roach) as one of the often-reported hybridizing pairs. The only account of such an event in Bosnia and Herzegovina has been in Modrac Reservoir. Using morphological and molecular markers, the presence of hybrids was surveyed, the hybridization direction was determined and the hybrid group structure in this ecosystem was evaluated. Our findings confirmed unhindered natural hybridization between roach and bream in Modrac Reservoir. Over 50% of the hybrid specimens were classified as F2 hybrids by the NewHybrids software, while the rest were categorized as pure parental form, making it the first such finding in Europe. The analysis of mitochondrial cytochrome b showed that 90% of hybrid individuals were of bream maternal origin. The hybrid group expressed higher mean values of observed heterozygosity and gene diversity than both parental species. Signs of introgressive hybridization between parental species were detected. The hybrid zone of Modrac Reservoir appears to follow the intermediate or “flat” hybrid model based on the balanced distribution of parental and hybrid genotypes. Further investigation is needed to elucidate the factors that enable the survival and mating success of post-F1 individuals.

The Largemouth bass (Micropterus salmoides) has been widely introduced worldwide as a popular recreational fishing species. The species was introduced to the freshwaters of Croatia in the early 20th century. This study assessed the distribution and status of Largemouth bass using field surveys, literature data and data collected by sport fisherman. The results indicate a wide distribution of M. salmoides in the Danube watershed and just one record in the Adriatic watershed (Neretva River). The species mostly inhabits oxbows, artificial lakes, reservoirs and channels with aquatic and riparian vegetation.

Fish assemblage of small and shallow marine lake called the Dead Sea, on Lokrum Island (Dubrovnik, Croatia) were investigated from March to July 2017 by using visual census. This salt lake is actually a cave that collapsed in the geological past and is connected to the sea by a submerged channel. Lokrum Island is a special reserve of forest vegetation since 1948. Today the island (72 ha) and the sea-belt (approx. 150 m) are also Natura 2000 site which includes eight Natura 2000 habitat types. Geomorphological phenomenon Dead Sea with its pit hole and the channel that connects the marine lake to the open sea is a Natura 2000 habitat type - Submerged or partially submerged sea caves. In spite of long natural history tradition in this area, there are no data on the biodiversity of Dead Sea. At least 15 fish species were recorded, of which some are listed on the IUCN Red list of Threatened Species: Chromis chromis, Tripterygion melanurum, Muraena helena, Scorpaena porcus, Microlipophrys dalmatinus, Diplodus vulgaris, Diplodus puntazzo, Sparus aurata. The main geostructural characteristic of Dead Sea (openness to light) significantly affect the species richness and fish assemblage structures inside. The species richness generally displayed a similar pattern with the nearby outer sea, whereas the patterns of fish abundance varied among species. Rare and cave exclusive species were not reported from this preliminary study. Although the natural values of the Lokrum Island represent unique whole of land and sea, Public Institution Lokrum Reserve does not currently manage the entire sea area of Natura 2000 Lokrum site. Therefore, this preliminary data represent guidelines not only for fish fauna conservation, but also with implications for conservation and management of Natura 2000 marine habitat types of Lokrum Island.

Individuals of Congridae leptocephali were accidentally caught during targeted research of small pelagic fish with small pelagic trawl nets (Italian-type otters) in the open waters of middle and south Adriatic during September 2010-2014. A total of 51 Conger conger, 19 Ariosoma balearicum and 3 Gnathophis mystax leptocephali were identified on the basis of their morphology, morphometric and meristic characteristics and pigmentation. 41 C. conger leptocephali were in premetamorphic stage, while 10 were in metamorphosis. The total number of myomeres ranged from 148 to 156, while the numbers of preanal myomeres differ for premetamorphic and metamorphic ones (75-81 and 55-57 respectively). According to morphometric and meristic characteristics of A. balearicum and G. mystax, all were in the premetamorphic stage. The total number of myomeres for A. balearicum varied between 125 and 134 and preanal myomeres from 108 to 112, while for G. mystax ranged from 134 to 137 and 114 to 117, respectively. The hatching dates back-calculated from the otolith microstructure of the field-caught C. conger leptocephali (8 to 11 months old) indicate a spawning season from late December through late August, with one annual peak occurring in August - September at the end of the warm season. Based on the age and distribution of leptocephali, as well as the upper-layer circulation and modelled mean current fields, a possible scenario of retention and dispersion of larvae suggesting South Adriatic Pit (SAP) as spawning area of Congridae species is explained.

The importance of transitional water ecosystems as nursery habitats and feeding grounds for juvenile fish species is well-known. However, detailed studies of colonization patterns of juvenile fish in specific ecosystem types are still missing. One hundred taxa ranging across more than 30 families (both marine and freshwater) were collected. Each taxon is characterized by trophic category, spawning area, ecological requests and determined as potential indicator/ new/ or alien species. The modified Estuarine Fish Index (M-EFI), which each aim to assess a different functional aspect of the estuarine fish assemblages and the integrated quality of the ecosystem (general degradation) was used. Also, assessment of anthropogenic pressure on coastal zone by calculating the LUSI index using the publicly available data was done. Pooling all species together, the structural features of the assemblages, relative abundance of families, and abundance of individual species all showed significant temporal patterns. Temporal segregation of species belonging to the same family or genus was obtained, suggesting that they avoid competition for space and resources by timing inward migration and peak occurrence differently. Of the environmental driving forces, salinity was the main factor affecting the distribution of individuals and species. The catch of a number of juvenile marine species confirmed the role of transitional waters as a nursery and feeding areas. With higher eutrophication, the transitional waters are more productive allowing more food both for resident and juvenile marine fishes. Also, productive waters offer more complex habitat providing micro niches and shelters for juveniles. The land impact, as sum of urban, agricultural and industrial pressures, is still low enough to encourage good ecological status. Low m-EFI values, obtained for low LUSI values is rather reflection of existing hydrographic and meteorological situation and seasonal variations than indicator of profound ecological changes in the transitional waters.

The present status, distribution, habitat, population structure, threats and conservation needs of the freshwater Neretva roach, Rutilus basak Heckel, 1843 are presented. Although inhabiting a restricted area which includes the Adriatic Sea watershed in Croatia and Bosnia and Herzegovina, only some biological and ecological population parameters are available. Lately, this species also faced with significant changes of taxonomy status raising the question of whether name changes have an impact on conservation status. Therefore more information about its biology is essential to develop appropriate conservation status and strategies. In this paper, we address these cases with a review of the relevant scientific literature. Our review speculates about possible outcomes of taxonomic change, primarily an impact on conservation efforts or affecting on reducing protection. Our study revealed that taxonomic change may have no predictable effects on conservation, while better understanding of biological- ecological status is always an important addition to our knowledge about the organisms that we want to protect. The combination of biological- ecological information and taxonomic status can be a useful tool for indicating failures in conservation management, but also for suggesting more effective actions. Finally, this study shows how this species can be good indicators for monitoring the success of biodiversity management in distributional areas

Lampetra soljani , new species, is described from the lower Neretva River in the Adriatic Sea basin. Previously it was identified as L. zanandreai . Based on morphological similarity and mitochondrial genetic data, it is related to L. lanceolata and L. ninae from the Black Sea basin. Lampetra soljani is distinguished from all other species of Lampetra by having a marmorate flank pattern in live, fully grown ammocoetes, and in some adults (vs. plain colour pattern). Lampetra soljani is distinguished from other Lampetra species by having three velar tentacles, 54–57 trunk myomeres between the last branchial opening and the anus, no posterial teeth and a bicuspid middle endolateral tooth. Lampetra soljani is also well distinguished by COI barcode data from its congeners. The new species is widespread in the Neretva River drainage and lampreys from Lake Skadar basin are likely to belong to this species also.