Odnosi dimenzija otolita s dužinom tijela kod europske jegulje Anguilla anguilla (Linnaeus, 1758) iz jadranskog sliva Crne Gore

This study examined the relationship between the sagittal otolith morphometric variables (length, height and weight) and body growth of the European eel. Eels that were studied ranged in total length from 11.2 to 79.5 cm. The relationships between the sagittal otolith variables and fish somatic growth were described with a non-linear function. The resulting coefficients of determination ((r^2)) ranged from 0.782 to 0.914. The variable most strongly related to fish size was found to be the sagittal otolith length (OL) with 91.4 % of the variability. The results of this study provide the first comprehensive data regarding the relationship between the sagittal otolith morphometric variables with the body length of Anguilla anguilla.U ovom radu se opisuje odnos između morfometrijskih varijabli sagitalnog otolita (duljina, visina i težina) i rasta tijela europske jegulje. Proučavane jegulje imale su raspon ukupne dužine od 11,2 do 79,5 cm. Odnos između sagitalnih otolitskih varijabli i somatskog rasta ribe opisani su nelinearnom funkcijom. Dobiveni koeficijenti određivanja ((r^2)) kretali su se od 0,782 do 0,914. Varijabla koja je najsnažnije povezana s veličinom riba utvrđena je na temelju sagitalne duljine otolita (OL) s 91,4% varijabilnosti. Rezultati ove studije pružaju prve sveobuhvatne podatke o odnosu između morfometrijskih varijabli sagitalnog otolita sa dužinom tijela Anguilla anguilla

Political and Socio-Economic Aspects of Fisheries in Inland and Coastal Waters of the Western Balkan

In the last decades in Europe, especially in the Balkan region, modernization of agriculture gave priority to economic growth without consideration of the environmental impact and sustainable development. Fisheries have traditional and essential importance of food and income in the Slovenia, Croatia, Serbia, Bosnia and Herzegovina, Montenegro, North Macedonia, and Albania (Western Balkans). The fisheries sector in Western Balkans is still not organized according to requirements of ecosystem integrity and sustainable utility. Practical application of the legislation indicates that the fishery has been developed without adequate harmonization with socio-economic characteristics, enforcement resources, and adequate control measures. Policymakers continue to be reluctant to give importance to the fishery sector, when allocating fishery resources among multifunctional users of water resources. In the following text, we gave review of the fisheries policy and socio-economic aspects of fishery sector in the Western Balkan countries. Critical fisheries policy and management measures are discussed and the propositions and recommendations of environmental sustainability measures under modern anthropogenic pressures are presented

Effect of the introgression of Atlantic brown trout, Salmo trutta, into Adriatic trout, Salmo farioides in a stream at the drainage area of the Adriatic Sea basin of Montenegro

Background. The diversity of wild trout stocks in Montenegro is compromised by insufficiently controlled stocking. Adriatic and Mediterranean areas show a high degree of endemism of the salmonid species, with numerous native Salmo taxa described. The invasive effect of brown trout, Salmo trutta Linnaeus, 1758, of the Atlantic haplogroup on the endemic Adriatic trout, Salmo farioides Karaman, 1938, in the drainage area of the Adriatic Sea basin is lower compared to the effect inflicted by S. trutta has on Salmo labrax Pallas, 1814 of the Danubian haplogroup. The presently reported study was intended to describe the genetic structure of the population of Adriatic trout, Salmo farioides, from the Mrtvica River, a right tributary of the Morača River, Montenegro, in order to get an insight into the spread of non-native strains and their introgression into the native Adriatic trout gene pool. Materials and methods. Trout specimens sampled from the lower section of the Mrtvica River from 2004 to 2007, and from its upper section in the spring of 2014, were analysed for their mtDNA haplotypes. Nuclear DNA markers (microsatellites, LDH-C1* gene) were also included in genetic analyses since mtDNA is inherited only maternally. After statistical analyses, relations between individuals from the upper and lower Mrtvica River were reconstructed. Results. Using both LDH-C1* and seven microsatellite loci with several alleles exclusive to S. trutta, an introgression was detected only in the upper reaches of the Mrtvica River, where only stream-dwelling trout form occurs. In the lower reaches no introgression was detected at all, as revealed by the absence of both the Atlantic mitochondrial haplotype and microsatellite alleles exclusive to S. trutta. Conclusion. The allelic frequency at seven microsatellite loci of Salmo spp. from the two river sections revealed very different population structure, as a consequence of a low rate of gene flow between them. In addition to the physical barrier that prevents Salmo sp. from the lower Mrtvica River to migrate to the upper river section, it seems that the opportunity to mate with the large pool of conspecifics, including lake-dwelling S. farioides (i.e., Salmo cf. dentex), prevents Salmo trutta from surviving at the lower stretch and spread to the rest of the Morača River and Lake Skadar systems

An assessment of regulation, education practices and socio-economic perceptions of non-native aquatic species in the Balkans

Alongside climate change, the introduction of non-native species (NNS) is widely recognized as one of the main threats to aquatic biodiversity and human wellbeing. Non-native species and biodiversity are generally low priority issues on the political agendas of many countries, particularly in European countries outside the European Union (EU). The objectives and tasks of this study were to address the policy regulation, education level, education practices, and socioeconomic perceptions of NNS in the Balkans. A questionnaire-based survey was conducted in Albania, Bosnia and Herzegovina, Montenegro, North Macedonia and Turkey (Balkan EU candidate and potential candidate members), in Croatia and Greece (Balkan EU Member States) and Italy (non-Balkan EU Member State). The EU Alien Regulation (1143/2014) concerning NNS is implemented in EU Member States and Montenegro, whereas Albania, Bosnia and Herzegovina and Turkey have not reported specific policy regulations for NNS. Permanent monitoring programmes specifically designed for NNS have not yet been established in the EU Member States. Most countries tackle the issue of NNS through educational activities as part of specific projects. Education level is indicative of the implementation of NNS policy regulation, and efforts are needed for the proper development of relative study programmes. Public awareness and educational preparedness concerning NNS in the Balkans were identified as poor. Strong programmes for management and education should be developed to increase public awareness to prevent further biodiversity losses in the Balkan region

Assessment of macro-, trace- and toxic elements in Small Indian mongoose, Herpestes auropunctatus (Hodgson, 1836), from Montenegro: potential use for biomonitoring

The aim of this study was to determine the concentrations of 28 elements in the liver, kidney, muscle, and heart of a small Indian mongoose from Montenegro. Element concentrations were determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Significant differences in elemental concentrations between analyzed tissues were observed for Ag, Al, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, P, S, Se, and Zn. The concentrations of Ag, Fe, Mo, and S were significantly different between all analyzed tissues. Muscle tissue is characterised by higher concentrations of some macroelements (K, Mg, S) and liver tissue by higher concentrations of some trace elements (Fe, Mn, Mo, and Zn). Cardiac tissue could be the target organ for bioaccumulation of Ag and Se. The molar ratio Se:Hg was higher than 1 in all studied tissues. There were few significant differences between element concentrations in mongooses from three analyzed (Airport, Saline, Inland) groups. Significantly higher concentrations of Ag and Se were found in liver tissue of Inland mongooses compared to animals from Airport and Saline. There were few significant differences (Zn in liver and muscle, Fe in muscle) in element concentrations between females and males

Prvi popis hrskavičnjača Crne Gore temeljen na kombinaciji monitoringa gospodarskog ribolova i građanske znanosti

Chondrichthyans are considered a highly threatened marine species, due both to the intense fishing pressure they have experienced in the world’s Oceans over several decades, and other threats, such as habitat loss, climate change and marine pollution. A rapid decline in their populations could trigger significant negative changes in marine ecosystems, highlighting the need for improved conservation measures. This study analyzes the current state of this group in the waters of Montenegro (in the southeastern Adriatic Sea). The first national checklist is provided here, comprising of 44 species, with information on their occurrence frequencies in Montenegrin fishery catches. The dataset used consists of 1469 records obtained from 281 field samplings conducted as part of the official monitoring of commercial fisheries (DCF-DCRF) as well as 1222 records derived from citizen science. The latter contributed significantly in documenting a greater number of species, particularly those considered threatened or rare in the region, and/or overlooked by DCF-DCRF monitoring. The frequency of species in Montenegrin catches is described based on the percentage of their records in the total number of records originating from local fisheries. The obtained results indicate that only 16% of the species recorded in Montenegro are commonly present in country’s catches, while 66% are either rare or not observed in local fishery. The creation of the country’s first checklist might contribute to overcoming drawbacks in national legislation and protection measures, notably by reporting the presence of endangered species in national marine waters.Hrskavičnjače se smatraju visoko ugroženim morskim vrstama zbog jakog ribolovnog pritiska kojem su izložene tijekom više desetljeća u svjetskim morima i oceanima, ali i zbog drugih negativnih utjecaja, poput gubitka staništa, klimatskih promjena i zagađenja mora. Ubrzano smanjenje njihovih populacija može pokrenuti negativne promjene u morskim ekosustavima, što dodatno naglašava potrebu za unaprjeđenjem mjera zaštite. Ovo istraživanje prikazuje analizu trenutnog stanja ove skupine organizama u crnogorskim vodama (jugoistočni Jadran). U radu je prikazan prvi popis hrskavičnjača, koji uključuje 44 vrste, s pojedinostima o učestalosti pojavljivanja u crnogorskim ulovima. Podaci se sastoje od 1469 zabilježenih nalaza u 281 terenskom istraživanju provedenom u okviru monitoringa gospodarskog ribolova (DCF-DCRF), kao i 1222 prijavljena nalaza prikupljena kroz „građansku znanost“ (citizen science). Građanska znanost značajno je doprinijela povećanju broja zabilježenih vrsta, posebice onih koje se smatraju ugroženim ili rijetkim u regiji i koje nisu zabilježene u DCF-DCRF monitoringu. Učestalost vrsta u crnogorskim ulovima prikazana je kao udio broja njihovih nalaza u ukupnom broju nalaza hrskavičnjača u lokalnom ribolovu. Dobiveni rezultati ukazuju da je tek 16% zabilježenih vrsta uobičajeno prisutno u ulovima u Crnoj Gori, dok je 66% ili rijetko u lovinama ili potpuno odsutno. Izrada prvog nacionalnog popisa hrskavičnjača može doprinijeti rješavanju nedostataka u nacionalnom zakonodavstvu i mjerama zaštite, posebice kroz zabilježene nalaze ugroženih vrsta u nacionalnim vodama

A treatise about reliability in dating events of evolutionary history of brown trout Salmo cf. trutta (Actinopterygii) at Western Balkans: Impassable barriers, isolation of populations and assistance of geological timeframe

A pool of data already existing about D-loop, i.e., the Control Region (CR) haplotypes of the mitochondrial DNA (mtDNA) of brown trout, Salmo trutta Linnaeus, 1758, tentative Adriatic trout Salmo farioides Karaman, 1938, and tentative Macedonian trout, Salmo macedonicus (Karaman, 1924), and their reconstructed phylogeography makes a good starting point for resolving their evolutionary history. That includes the dating of particular events in it. The events have hitherto been dated using the method of a molecular clock. Various calibrations were applied for the mutation rate, owing to the incongruence between the time of divergence that various authors notified and general knowledge about events in geological history and the periods in which they occurred in the Mediterranean region. Since geological history events were mandatory for setting the scene for the evolutionary history of brown trout, the incongruence between them has questioned the molecular clock calibration’s validity. From results about both the phylogeography and phylogenetic relations between native haplotypes (both partial and whole CR sequences) and the population genetics that characterized particular populations, we calculated the time of divergence between haplotypes in the regions of the western part of the Balkans: Iron Gate broader area in eastern Serbia, continental Montenegro and south-eastern Serbia. The distinct status of adjacent populations was verified by frequencies of microsatellites’ alleles and the STRUCTURE analysis that examined the significance of differences between them. In particular, we examined the populations that were clearly separated either by physical barriers, such as a waterfall in eastern Serbia (e.g., the upper and lower River Rečka supplemented by nearby rivers Vratna and Zamna), or by underground drops in Montenegro (e.g., upper and lower River Zeta, and rivers Nožica and lower River Mrtvica as isolated counterparts). We used the so far most common substitution rate of 1% in a million years’ (MY) period. The divergence times we obtained were compared to the events known for the region from available geological history data. There was a fairly good congruence between the dating obtained by the molecular clock method and that by geological history where the advanced, i.e., modern haplotypes, were concerned. In contrast, the congruence was worse for dating of divergence when more ancient haplotypes were in question, being much better if the mutational rate would be decreased to lower rates. That supported results both from the Rate Correlation Test about the independence of evolutionary rates in different lineages of brown trout, and from the Molecular Clock Test, which revealed that the evolutionary rate throughout the phylogenetic tree is not equal. That implies a difference in the speed of evolution in them, which was likely slower and faster, in the ancient, pre-Pleistocene haplotypes and the advanced, Pleistocene ones, respectively. The setting of the variable, or non-linear (i.e., logarithmic) speed of evolving seems helpful, since the early cladogenesis with the dominance of mutations was most likely combined afterwards with the acting of other evolutionary mechanisms, especially of genetic drift in populations that passed through the bottleneck episodes of the abrupt decrease in population size during the unfavourable periods of their evolutionary history

Changing climate may mitigate the invasiveness risk of non-native salmonids in the Danube and Adriatic basins of the Balkan Peninsula (south-eastern Europe)

Salmonids are an extensively hatchery-reared group of fishes that have been introduced worldwide mainly for their high commercial and recreational value. The Balkan Peninsula (south-eastern Europe) is characterised by an outstanding salmonid diversity that has become threatened by the introduction of non-native salmonids whose potential risk of invasiveness in the region remains unknown and especially so under predicted climate change conditions. In this study, 13 extant and four horizon non-native salmonid species were screened for their risk of invasiveness in the Danube and Adriatic basins of four Balkan countries. Overall, six (35%) of the screened species were ranked as carrying a high risk of invasiveness under current climate conditions, whereas under predicted conditions of global warming, this number decreased to three (17%). Under current climate conditions, the very high risk (‘top invasive’) species were rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta (sensu stricto), whereas under predicted climate change, this was true only of O. mykiss. A high risk was also attributed to horizon vendace Coregonus albula and lake charr Salvelinus namaycush, and to extant Atlantic salmon Salmo salar and brook trout Salvelinus fontinalis, whose risk of invasiveness, except for S. fontinalis, decreased to medium. For the other eleven medium-risk species, the risk score decreased under predicted climate change, but still remained medium. The outcomes of this study reveal that global warming will influence salmonids and that only species with wider temperature tolerance, such as O. mykiss will likely prevail. It is anticipated that the present results may contribute to the implementation of appropriate management plans to prevent the introduction and translocation of non-native salmonids across the Balkan Peninsula. Additionally, adequate measures should be developed for aquaculture facilities to prevent escapees of non-native salmonids with a high risk of invasiveness, especially into recipient areas of high conservation value

Alien freshwater fish species in the Balkans-Vectors and pathways of introduction

Fish introductions, particularly in areas of high biological diversity and endemism, represent a major threat for biodiversity. In the Balkan Peninsula, 60 fish species have been introduced to date, of which 36 have become naturalized in inland waters. Since the Balkans are one of the world's 35 biodiversity hot spots, this large presence of alien fish species poses a serious threat for the stability of freshwater ecosystems and the survival of the native ichthyofauna and of aquatic biodiversity in general. The motivation for the introductions, and the historical timeline, varies among the Balkan states. Despite recent attempts to implement and align legislation aimed at preventing the introduction of potentially invasive species, and the implementation of rigorous controls of introductions and increased protection of open waters, the majority of current introductions remain intentional, primarily via aquaculture. This review article provides a historical overview of freshwater fish introductions, the motivation behind them a nd the current distribution of alien freshwater fishes in the Balkans. The ecological implications and future perspectives concerning alien fish species in the region are also discussed