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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.

Filogenija i sistematika u drugoj polovini 20. veka sve više se zasnivaju na molekularnim metodama kojima se nastoje rešiti kompleksni odnosi između rodova i vrsta u okviru porodice Salmonidae. U ovom radu, kao molekularno-genetički markeri korišćeni su kontrolni region mitohondrijalne DNK (CR mtDNK), mikrosateliti i jedarni LDH-C* gen, važan dijagnostički marker koji se dobro pokazao u rešavanju problema postglacijalne kolonizacije populacija S. trutta. Krajem 20. veka definisane su jasne filogeografske linije pastrmki – atlantska (AT), dunavska (DA), mediteranska (ME), jadranska (AD) i marmoratus linija (MA). Zapadni deo Balkana čini jadransko-mediteranska oblast sa najvećim fenotipskim diverzitetom među pastrmskim populacijama, dok veliki deo unutrašnje teritorije pripada crnomorskom slivu. U ovoj disertaciji analizirane su potočne pastrmke iz reka crnomorskog sliva u Bosni i Hercegovini, i reka jadranskog sliva u Crnoj Gori, sa ciljem utvrđivanja genetičke strukture i raznovrsnosti populacija kompleksa S. cf. trutta na području zapadnog Balkana, uzimajući u obzir potencijalne hibridizacione procese. U rekama crnomorskog sliva detektovana su dva haplotipa DA (Da2, Da22), i jedan AT linije (At1). U jadranskom slivu ustanovljeno je šest haplotipova iz tri linije: AD (ADcs11, Ad+Prz), DA (Da1, Da2) i AT (A17, At1). U gotovo svim rezidentnim populacijama primećeno je ukrštanje između autohtonih i introdukovanih jedinki. Invazivni efekti stranih haplotipova potočne pastrmke (At1, A17, Da2) u analiziranim rekama otkriveni su u proceni rizika od strane autora navedenih u ovoj disertaciji. Nužno je ustanoviti politiku upravljanja pastrmskim ribolovom i mere konzervacije kako bi se redukovao rizik koji neadekvatno poribljavanje predstavlja po autohtoni fond potočne pastrmke., Phylogeny and systematics in the second half of the 20th century are mostly based on molecular methods that seek to resolve complex relationships between genera and species within the Salmonidae family. In this research, the following molecular molecular genetic markers were used: mitochondrial DNA (CR mtDNA) control region, microsatellites and nuclear LDH-C * gene, an important diagnostic marker that has proven particularly well for addressing postglacial colonization of S. trutta populations. At the end of the 20th century clear phylogeographic lineages of brown trout were defined – Atlantic (AT), Danubian (DA), Mediterranean (ME), Adriatic (AD), and marmoratus (MA). Western part of Balkan is made up of the Adriatic-Mediterranean area, which represents the area of greatest phenotypic diversity among trout populations, while a large part of the its inland territory belongs to the Black Sea basin. In this dissertation, brown trout from the rivers of the Black Sea basin in Bosnia and Herzegovina, and the rivers of the Adriatic basin in Montenegro were analyzed, with the aim of determining the genetic structure and diversity of populations of the complex of brown trout S. cf. trutta in the Western Balkans, taking into account potential hybridization processes. In rivers of the Black Sea basin, three haplotypes were detected, two of which belong to the DA lineage (Da2 and Da22), and one haplotype belongs to the AT lineage (At1). Six haplotypes from three lineages were detected in the Adriatic basin: AD (ADcs11, Ad + Prz), DA (Da1, Da2) and AT (A17, At1). In almost all resident populations, crossing between autochthonous and introduced individuals was observed. The invasive effects of foreign haplotypes of brown trout (At1, A17, Da2) in analyzed trout rivers were discovered in a risk assessment by the authors cited in this dissertation. There is a great need to establish a trout fisheries management policy and conservation measures to reduce the possible risk that inade

The surface area of Montenegro’s portion of the Black Sea drainage basin is 7075 km2, or 0.9% of the entire basin, and is made up of the rivers Tara, Piva, Lim, Ćehotina and Ibar, and Lake Plav. The major polluters of watercourses are wastewaters and solid waste from inhabited settlements. According to water categorization regulations, the rivers of the Danube Basin in Montenegro are, based on the status quo, classified into four quality classes. Thus, the mid- and lower courses of the larger rivers fall within quality classes II and III. The water quality of the Lim, downstream of Berane, worsens at its exit from Montenegro and falls into quality class III. The Ibar profile downstream of Bać is largely out of a prescribed class. The Ćehotina downstream of Pljevlja is in water quality class III, and occasionally out of a prescribed class. The Tara belongs to the Durmitor National Park, but its water quality is class I only at its most upstream profile; its profiles downstream of Kolašin are from class II to class III. These findings are confirmed by analyses of their aquatic macroinvertebrate communities, i.e. Oligochaeta, as bioindicators of water quality. The ichthyofauna of the Danube Basin rivers in Montenegro comprises 20 fish species. Hydromorphological alterations of watercourses, such as dam construction, have a significant effect on fish populations. Thus, the dam on the Piva river has a negative effect on the fish population, presenting a barrier to migration routes, as is the case with huchen or Danube salmon (Hucho hucho).

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.

Kontrolna regija mitohondrijske DNK pokazala se kao odličan filogeografski marker kad je kompleks potočne pastrmke (Salmo cf. trutta) u pitanju. Krajem 20. veka ustanovljeno je pet osnovnih filogeografskih linija (haplogrupa) potočne pastrmke: dunavska, atlanska, mediteranska, jadranska i marmoratus koje uglavnom korespondiraju sa odgovarajućim slivovima. Analizirane jedinke na području Srbije nosile su haplotipove dunavske, atlanske i jadranske haplogrupe. Najdominantniji haplotip u slivu Crnog Timoka i rekama desne obale Dunava u Đerdapskom regionu pripadao je dunavskoj liniji i opisan je pod imenom Da23c (ACCN KC630984). Obzirom da je ovaj haplotip zasada otkriven samo u ovoj oblasti i to sa velikom učestalošću smatra se autohtonim za ovu regiju. U okviru Đerdapskog regiona uočen je i haplotip Da1, ali samo u Rečkoj reci u njenom desnom delu iznad nepremostive prepreke, vodopada visine 10 m. Kao pleziomorfni u odnosu na haplotip Da23c i široko rasprostranjen na ovom delu Balkanskog poluostrva postoji velika verovatnoća da je i on autohton za ovo područje, međutim nije isključena ni mogućnost da je unesen poribljavanjem. U okviru sliva Crnog Timoka osim autohtonog haplotipa Da23c otkriven je i Da2, koji je najverovatnije alohton. U prilog tome govore činjenice o rasprostranjenju haplotipova na zapadnom Balkanu, kao i podaci o korišćenju jedinki ovog haplotipa za poribljavanje i gajenje u Austrougarskoj, a kasnije u celoj Evropi i Srbiji. Osim dunavske u okviru šireg područja Đerdapa otkriveno je i prisustvo atlanske linije u rekama Brnjica, Dobrinjska, Porečka i Vratna, a samo u poslednjoj jedinke atlanskog haplotipa koegzistiraju sa pastrmkama koje nose autohtoni haplotip, Da23c. Atlanski haplotip ne smatra se autohtonim za Balkansko poluostrvo, pa je najverovatnije u reku Vratnu dospeo poribljavanjem, a analize jedarnog gena, laktat dehidrogenaze, pokazale su da se ove jedinke međusobno ukrštaju. Programske analize podataka osam mikrosatelitskih lokusa ukazale s, Control Region of mitohondrial DNA is a good phylogeographic marker for brown trout species complex (Salmo cf. trutta). Five main brown trout phylogeographic lineages (haplogroups) that mostly correspond to the particular basins have been established at the end of 20th century: Danubian, Atlantic, Mediteranean, Adriatic and marmoratus. Individuals from Serbia held haplotypes of Danubian, Adriatic and Atlantic haplogroups. Prevailing haplotype in the River Crni Timok drainage area and in the right tributaries of the River Danube from Đerdap region is Da23c (ACCN KC630984) of Danubian haplogroup. This haplotype is considered indigenous there since it has been found only in this area and with a great frequency. Another haplotype also detected in the Đerdap region is Da1, but only in the River Rečka, in its right fork above the 10 m high waterfall, which is an impassable obstacle for upstream dispersal of brown trout from downstream section. Considering its plesiomorphic character compared to haplotype Da23c and its wide distribution in this part of Balkan Peninsula, there is a high probability that it is indigenous for this region, as well. However, the possibility that it has been imported by stocking activities cannot be excluded. In addition to the indigenous haplotype Da23c, the haplotype Da2 was also detected in the Crni Timok drainage area, probably as an allochthonous one. This was supported by haplotype distribution in Western Balkans, as well as by history of stocking and breeding with the Da2 haplotype in Austria-Hungary and later, both in middle and southeastern Europe, including Serbia. Individuals of the Atlantic haplogroup were detected in rivers Brnjica, Dobrinjska, Porečka and Vratna of the broader Đerdap area. Only in the last river these individuals coexist in sympatry with brown trout of indigenous Da23c haplotype. Since Atlantic haplotype was not considered indigenous for Balkan Peninsula, it has been probably introduced there by stocking. Analysis