Dinaric Alps or Dinaric Karst water systems inhabit 25% of the total of 546 fish species in Europe. Watercourses of this area inhabits a large number of endemic species of fish. The river Neretva and its tributaries represent the main drainage system in the east Adriatic watershed and the foremost ichthyofaunal habitat of the region. According to Smith & Darwall (2006) the Neretva river, together with four other areas in the Mediterranean, has the largest number of threatened freshwater fish species.
Degree of endemism in the karst eko-region is greater than 10% of the total number of fish species. Numerous species of fish that inhabited this area live in very narrow and limited areal and are vulnerable, so they are included on the Red List of endangered fish and the IUCN-2006. The Adriatic basin has 88 species of fish, of which 44 are Mediterranean endemic species, and 41 are Adriatic endemic species. More than half of the Adriatic river basins species of fish inhabit the Neretva, the Trebišnjica section known as Ombla, the Trebišnjica, the Morača rivers and their tributaries, and more than 30 are indigenous species.
Salmonids |
| Neretva River watershed |
Salmonids fishes from the Neretva basin show considerable variation in morphology, ecology and behavior. The Neretva also has many other endemic and fragile life forms that are near extinction.
Among most endangered are three endemic species of the Neretva trout:
- Neretvan Softmouth trout or Adriatic trout (Bosnian: Neretvanska mekousna pastrmka also Bosnian: Jadranska pastrmka) (Salmothymus obtusirostris oxyrhinchus Steind.);
- Salmo dentex or Toothtrout (Bosnian: Zubatak) (Salmo dentex); and
- Marble trout (Bosnian: Glavatica also Bosnian: Gonjavac) (Salmo marmoratus Cuv.).
- Neretvan brown trout (which is Adriatic lineage of Brown trout, Salmo trutta) (Bosnian: Neretvanska potočna pastrmka also Bosnian: Zubara)
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| Neretva and tributaries |
Softmouth trout (also Adriatic trout)
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| Mekousna neretvanska - Neretvan Softmouth (Salmo obtusirostris oxyrhynchus) |
Marble trout
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| Glavatica neretvanska - Neretvan Marble trout (Salmo marmoratus) |
Tooth trout
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| Zubatak neretvanski - Neretvan Tooth trout (Salmo dentex) |
Neretvanski zubatak, Salmo dentex je slabo istražena vrsta, endemska za vode Jadranskog slijeva. Pisani materijal o vrsti je oskudan i ograničen na originalne opise iz rijeke Neretve od Heckel-a (1852). Istraživanjima u razdoblju 2000-2008 godine utvrđeno i opisano je postojanje populacije zubatka u jezerima, potocima i močvarama Parka Prirode "Hutovo blato", rijeci Neretvi od Mostara do samog ušća. Zubatak po nekim podacima može narasti i do 30 kilograma, a u ovim istraživanjima najveši je težio 11,2 kilograma (!). Zimi ulazi u vode donje Neretve u Hrvatskoj, te se lovi na samom ušću (!). Tijekom životnog ciklusa primjerci između 100-500 grama ulaze u močvare Parka Prirode "Hutovo blato", bogate autohtonom ihtiofaunom i s posebnim temperaturnim uvjetima, te se pretpostavlja da je ova značajka važna za recentnu specijaciju ove vrste od ishodišne neretvanske pastrve. Praksa poribljavanja alohtonim pastrvama u zadnjih 50-tak godina dovela je do križanja autohtonih i alohtonih pastrva donje Neretve i njihovih fertilnih hibrida, što danas rezultira utvrđenim postojanjem večeg broja fenotipskih formi. Ovo ukazuje da su potrebne žurne mjere za očuvanje autohtonih genetičkih značajki vrste formiranjem čistih matičnih stokova, te akvakulturna istraživanja u svrhu proizvodnje mlađi za uzgoj i poribljavanje.
Neretvan toothtrout, Salmo dentex is relatively unknown species, endemic for rivers of Eastern Adriatic. Reports on it are scarce and limited to original descriptions by Heckel (1852). Research in the period 2000-2008 reported existence of populations of neretvan toothtrout in the lakes, streams and wetlands of Nature Park "Hutovo blato", Neretva River flow from town of Mostar to river mouth. According to some data the species could grow to 30 kilos and the heaviest we caught was 11, 2 kilos. During winter it enters water of Lower Neretva in Croatia, and was caught even on river mouth. During life cycle the younger specimens (100-500 grams) enter wetlands of Nature Park "Hutovo blato", rich with autochthonous fish and with special temperature regime. We proposed that this characteristic is important for recent speciation from ancient Neretvan trout. The practice of stock enhancement with introduced trout in the last 50-years lead to crossing of autochthonous and introduced trout and their fertile hybrids, what resulted in existence of numerous phenotypic forms. Quick measures for protection of native genetic characteristics of the toothtrout are necessary. The crucial steps are establishment of broodstock, and aquaculture research for production of juveniles for breeding and stock enhancement.
(Autor: prof. Branko Glamuzina - Neretvanski zubatak, Salmo dentex- značajke, zaštita i akvakultura - Neretvan toothtrout, Salmo dentex- characteristics, protection and aquaculture)
The genetic structure of Salmo dentex and its phylogenetic relations to sympatric salmonids in the Neretva and Skadar River basins were evaluated using mitochondrial DNA (mtDNA) control region, eight microsatellites, and somatolactin (SL) gene. In the Neretva River basin of Bosnia-Herzegovina, the results based on mtDNA analysis showed extensive haplotype sharing between S. marmoratus, S. dentex, and S. trutta, and were therefore not conclusive; however, F-statistics and assignment testing based on nuclear DNA markers indicated that S. dentex of the Neretva basin were grouped in a genetically unified cluster with S. marmoratus in the Neretva basin. Using the same analytical approach, S. dentex from the Skadar basin in Montenegro appeared to be genetically distinct from S. marmoratus in the same basin and indistinct from local S. trutta. Molecular data also indicated that S. dentex of the Neretva basin in Bosnia-Herzegovina are not closely related to S. dentex of the Skadar basin in Montenegro. Based on these results, we hypothesize S. dentex to be a particular life history form of S. marmoratus in the Neretva basin and of S. trutta in the Skadar basin. These results clearly demonstrate that S. dentex does not represent a monophyletic lineage and should not be considered a distinct species.
(Autor: grupa autora - Resolving taxonomic uncertainties using molecular systematics: Salmo dentex and the Balkan trout community)
Brown trout (Adriatic lineage)
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| Potočna neretvanska pastrmka (S. trutta Adriatic lineage) |
According to mtDNA haplotypes, Neretva basin is inhabited by three lineages of S. trutta: native Adriatic lineage and two introduced lineages (the Danubian and Atlantic). Using nuclear DNA markers, natural introgression between S. obtusirostris and native S. trutta was detected being biased toward S. trutta, which may explain the preservation of the S. obtusirostris integrity despite observed interspecific hybridisation.
On the brink of extinction
All three endemic trout species of the Neretva are endangered mostly due to the habitat destruction or construction of large and major dams (large as higher than 15-20 m; major as over 150-250 m) in particular and hybridization or genetic pollution with introduced, non-native trouts, also from illegal fishing as well as poor, incompetent and irresponsible management of water and fisheries especially in form of introduction of invasive allochthonous species (dams, overfishing, mismanagement, genetic pollution, invasive species).
According to studies carried on by Andrej Razpet, expert ichthyologist of BTRG (Balkan Trout Restoration Group):
According to studies carried on by Andrej Razpet, expert ichthyologist of BTRG (Balkan Trout Restoration Group):
The Neretva basin is the main salmonid habitat in the Adriatic part of the south-western Balkans. On the basis of external morphology, several sympatric salmonid species (i.e., Salmo trutta, S. marmoratus, S. obtusirostris, S. farioides and S. dentex) were described, however, original descriptions were vague and some of the names are now questionably valid, which makes taxonomy unclear. In order to revise the existent taxonomy of salmonid taxa in the Neretva basin, to determine their mutual relationship and relationship to valid salmonid taxa, we conducted genetic screening of 206 specimens, randomly sampled in the upper part of the Neretva basin. On the basis of mtDNA, we determined the phylogeographic lineage of individuals, whereas population genetic structure and introgression were determined using microsatellite and SNP data. According to mtDNA haplotypes, Neretva basin is inhabited by S. obtusirostris and three lineages of S. trutta: native Adriatic lineage and two introduced lineages (the Danubian and Atlantic). S. dentex and it S. marmoratus exhibit the Adriatic lineage mtDNA haplotype. Using nuclear DNA markers, natural introgression between S. obtusirostris and native S. trutta was detected being biased toward S. trutta, which may explain the preservation of the S. obtusirostris integrity despite observed interspecific hybridisation. Hybridisation between the native and introduced lineages of S. trutta was detected as well, representing a potential threat to sympatric co-existence of all the native lineages.
Cyprinids
Same as the Neretva salmonids, most endangered of cyprinids (Cyprinids - Cyprinidae family) are those of endemic species.
Especially interesting are five Phoxinellus (sub)species that inhabits isolated karstic field or karstic plains (fields) of eastern as well as western Herzegovina and West Bosnia, which eventually drains its waters to Neretva watershed and/or coastal drainages of south-eastern Dalmatia in Croatia.
Karst Minnow
(Bosnian: Gatačka gaovica) (Phoxinellus metohiensis). It is considered Vulnerable (VU).
South Dalmatian Minnow
(Bosnian: Trebinjska gaovica) (Phoxinellus pstrossii). It is threatened but with Data Deficient (DD) fish vulnerability is not designated on IUCN Red List of Threatened Species Version 2009.1.
Dalmatian Minnow
(Bosnian: Popovska gaovica) (Phoxinellus ghetaldii). It is considered Vulnerable (VU).
Adriatic Minnow
(Bosnian: Uklja; Croatian: Pijurica) (Phoxinellus alepidotus) endemic to Bosnia and Herzegovina and Croatia, occurs in lowland water bodies, with little current. Is threatened due to pollution and habitat destruction. It is considered Endangered (EN).
Spotted Minnow
(Bosnian: Gaovica) (Phoxinellus adspersus) endemic to Bosnia and Herzegovina and Croatia. This species is present in the Tihaljina River, which is fed by underground waters from Imotsko field and is connected to the Trebižat river via the Mlade river also occurs in Mostarsko Blato wetlands. Fish was found in the source of the Norin River, a right-hand tributary of the lower Neretva at Metković, in Croatia, at Kuti Lake, the left-hand tributary of the lower Neretva, at Imotsko field in Crveno Lake and the Vrljika River drainage and near Vrgorac in the Matica river system. It is considered Vulnerable (VU).
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| Gaovica |
Minnow Nase
(Bosnian: Podbila) (Chondrostoma phoxinus) It is considered Critically Endangered (CR)
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| Podbila |
Neretvan Nase
(also Dalmatian Nase also Dalmatian Soiffe) (Bosnian: Neretvanska podustva) (Chondrostoma knerii) is a fish species endemic to the Neretva river. Neretvan Nase is mainly distributed in the lower parts and delta of the Neretva river shared between Croatia and Bosnia and Herzegovina, the Neretva left tributary Krupa River, Nature Park Hutovo Blato wetlands, Neretva Delta wetlands. Occurs in water bodies with little current. Is threatened by habitat destruction and pollution. It is considered Vulnerable (VU).
Adriatic Dace
Adriatic Dace (Jadranski klijen) (Bosnian: Strugač; Croatian: Sval) also Balkan Dace (Squalius svallize also Leuciscus svallize Heckel & Kner 1858) endemic to Bosnia and Herzegovina and Croatia, also to Montenegro and Albania. Adults inhabit water bodies on the low plains, with little current, lakes. Feed on invertebrates. It is threatened due to pollution, the habitat destruction and especially due to introduction of other species. It is considered Vulnerable (VU).
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| Adriatic Dace - Jadranski klijen, Strugač ili Sval |
Illyric Dace
(Bosnian: Ilirski klijen) (Squalius illyricus also Leuciscus illyricus Heckel & Kner 1858) inhabits karstic waters of Bosnia and Herzegovina, Croatia and Albania. Occurs in water courses on low plains, with little current. Feeds on invertebrates. Is threatened due to habitat destruction, pollution and the introduction of other species. It is considered Near Threatened (NT).
Turskyi Dace
(Bosnian: Turski klijen) (Leuciscus turskyi also Squalius turskyi turskyi and Telestes turskyi) inhabits karstic waters, lake Buško Blato in Bosnia and Herzegovina and the Krka and the Čikola rivers in Croatia. Occurs in water courses on the low plains, with little current and in lakes. Feeds on invertebrates. Is threatened due to water abstraction and pollution. It is considered Critically Endangered (CR).
Dalmatian Barbelgudgeon
(Bosnian: Oštrulja) (Dalmatian Barbelgudgeon - Aulopyge hugeli) inhabits karstic streams of Glamocko Polje, Livanjsko Polje and Duvanjsko Polje, lakes Buško Blato and Blidinje in Bosnia and Herzegovina and Cetina, Krka and Zrmanja river drainages in Croatia. Occurs in lentic waters, feeds on plants. Fish is threatened by water pollution and habitat destruction. Migratory in Livanjsko Polje. It is considered Endangered (EN).
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| Oštrulja |
Cobitidae
Neretvan Spined Loach (Bosnian: Neretvanski vijun) (Cobitis narentana Karaman, 1928) is Adriatic watershed endemic fish, inhabits a narrow area of the Neretva watershed in Croatia and Bosnia and Herzegovina (Mrakovčić et al., 2006). In Bosnia and Herzegovina inhabits only downstream of the Neretva river and its smaller tributaries like the Matica river (section of Trebižat River). In Croatia Neretvanski vijun is strictly protected species and inhabits only in the Neretva delta and its smaller tributaries the (Norin) and lake systems of the Neretva delta (Baćina lakes, Kuti, Desne, Modro oko) (Mrakovčić et al., 2006). It is considered Vulnerable (VU).
Neretva delta endemics
Ichthyofauna of the Neretva delta is rich in endemic species, and there are more than 20 endemic species, of which 18 species are endemic species of Adriatic watershed, and three endemic species in Croatia. Nearly half of species (45%) of the total number of species that inhabit this area are included in one of the categories of threat, and are mainly endemic species.
