This species cannot be distinguished from the congeneric Italian Bleak (Alburnus arborella) by morphological characters, and additional systematic research is recommended (Geiger et al. 2014).

Global and European regional assessment: Near Threatened (NT)
EU 27 regional assessment: Vulnerable (VU°)

The Neretva Bleak has a restricted range (extent of occurrence (EOO) c. 9,140 km²), which meets the threshold for the Vulnerable category under Criterion B1 (EOO < 20,000 km²). The quality of habitat is estimated to be declining, but the number of locations is unknown and it is unclear whether the extant subpopulations are severely fragmented. There is no evidence that the number of mature individuals demonstrates extreme fluctuations. Therefore, this species is assessed as Near Threatened at the global and European regional scales, because it is close to qualifying for Vulnerable under Criterion B.

In the EU 27 member states, the EOO is c. 1,416 km², which meets the threshold for Endangered under Criterion B1 (EOO < 5,000 km²), and it is present at four threat-defined locations where habitat quality is estimated to be declining. However, these sites are linked to a transboundary river system inhabited by the largest extant stock, hence its assessment is downlisted by one category from Endangered to Vulnerable under Criterion B (B1ab(iii)).

This species is endemic to the Neretva and Trebišnjica river systems, which together comprise a single large catchment in the Dinaric Karst region of the Western Balkans.

It is currently present in the Neretva main stem and tributaries from the river's delta upstream to the Salakovac hydroelectric dam, including the Baćina and Kuti lake basins, Vgorsko polje (Vrgorska Matica River), the Crna Rijeka, Norin, Trebižat, Buna, Bregava and Krupa rivers, and the Hutovo Blato wetland. It has not been recorded in Imotsko polje in the upper Trebižat River.

In the Trebišnjica River catchment it is reported from Popovo and Gatačko (Mušnica River) poljes.

This species' current population size and trend have not been quantified, and the number of subpopulations is unknown.

Between the 1990s and 2000s it was extirpated from the Jablaničko and Ramsko reservoirs in the upper Neretva catchment (see 'Threats').

This species inhabits perennial karstic rivers and associated wetlands, and has colonised several artificial accumulation lakes.

The Vrgorska Matica, Trebišnjica and Mušnica rivers are spring-fed sinking rivers which flow through karstic depressions known as poljes. They are characterised by significant seasonal fluctuations in discharge, and are connected to the Neretva system via subterranean karstic conduits.

A number of its habitats naturally flood on an annual basis, providing spawning and nursery zones for resident fishes.

It feeds predominantly on pelagic zooplankton, crustaceans and aquatic invertebrates, with some flying and terrestrial arthropods taken at the water surface. The maximum recorded weight is c. 100 g.

Sexual maturity is attained at age 2-3+, and the annual reproductive period extends from April to June. Nuptial adults are understood to migrate short distances to spawning sites in floodplains, side-channels, and tributaries plus some associated wetlands, e.g., Hutovo Blato in Bosnia and Herzegovina. Juveniles remain in the vicinity of spawning sites for several months post-hatching, typically until October.

This species is plausibly threatened by river regulation and other forms of anthropogenic habitat degradation.

In particular, construction of four large hydroelectric dams along the middle section of the Neretva River main stem since the 1950s has altered natural flow and sedimentation regimes and potentially blocked migration routes, fragmented subpopulations, and markedly reduced the extent of habitat for all life stages. The scale of annual flooding in the Hutovo Blato wetland has declined significantly due to reduced discharge of the Neretva and some affluent springs such as Čapljina, which is also exploited for hydropower generation. The southern part of the wetland was partially impounded in 1979, and a proposed plan to divert water from Hutovo Blato for domestic use may further reduce habitat quality.

Hydroelectric dams also create unnatural fluctuations in discharge and water temperature (hydropeaking and thermopeaking) which bring about artificial dewatering of downstream river stretches and loss of stable nursery habitat for juveniles. Furthermore, the combined effect of hydropeaking, dam flushing operations and changes in land use is likely to have increased accumulation of fine sediments and negatively impacted foraging and reproductive success at some locations. The proposed construction of around 70 additional hydroelectric projects in the upper reaches of the river, plus an ongoing expansion scheme in the Trebišnjica River (see below) together represent a plausible future threat to the entire Neretva ecosystem.

The extent and quality of habitat in the Neretva catchment has been further diminished by bank stabilisation, channelisation and other efforts to enhance flood protection or exploit water resources for irrigated agriculture. In the river's delta, only three of its original twelve branches remain and most former marshes and lakes have been reclaimed for agriculture since the 1960s. Diffuse and point source agricultural, domestic and industrial pollution has resulted in eutrophication or discharge of toxic substances at some locations. The industrial extraction of riverine gravel and sand for urban development has taken place since the 1970s, causing the river bed to become deeper in places and hampering the transport of heavy sediments.

Elsewhere, Vrgorsko polje is almost entirely turned over to agriculture, and the Vrgorska Matica River is extensively impacted by eutrophication and water abstraction.

The hydrological regime of Gatačko polje has been significantly disrupted due to construction of two accumulation dams in its upper reaches. In addition, the northwestern part of the polje has been extensively degraded since the 1970s following construction of a coal-fired power plant and open-pit mining operation. Water is directed through a pipeline from the two reservoirs to supply the power plant, and no longer flows through the polje. A number of the Mušnica River's tributaries have been channelised in order to prevent flooding in the area around the mine, and the lower reaches of the Mušnica main stem are also regulated.

A number of non-native fish species that are documented to exert negative effects on native ichthyofauna through predation, resource competition or habitat degradation are established in different parts of the Neretva Bleak's range, including Eurasian Pikeperch (Sander lucioperca), Pumpkinseed (Lepomis gibbosus), Largemouth Bass (Micropterus salmoides), Eurasian Ruffe (Gymnocephalus cernua), Prussian Carp (Carassius gibelio), Common Carp (Cyprinus domestic strain), Topmouth Gudgeon (Pseudorasbora parva), Brown Bullhead (Ameiurus nebulosus) and Rainbow Trout (Oncorhynchus mykiss). The Neretva Bleak is among the major dietary components of Eurasian Pikeperch in artificial lakes, and this may have accelerated its extirpation from the Jablaničko and Ramsko reservoirs.

Future threats involve the channelling and pumping of water from the Mušnica River to adjacent Nevesinjsko polje within the framework of the ongoing (2023) "Upper Horizons" hydropower strategy, which aims to artificially redirect water from poljes draining to the Buna and Bregava rivers in the lower Neretva catchment to an accumulation reservoir in the Trebišnjica River through a cascading series of canals, tunnels and hydroelectric stations. Once complete, the scheme is projected to significantly reduce discharge in the lower Neretva, with a range of projected negative impacts on Hutovo Blato and the river's delta region.

The Trebišnjica River system has already been heavily modified by the "Lower Horizons" hydropower scheme, which was initiated during the 1960s and today comprises several dams and hydroelectric plants. The artificial lakes associated with these barriers have favoured the widespread establishment of non-native fish species. Since 1978, much of the main stem has been converted into a 65-kilometre canal designed to prevent loss of water into the surrounding karst, and former temporal wetlands at some locations, e.g., Popovo polje, no longer exist.

This species is harvested for local human consumption in Bosnia and Herzegovina, where it is considered to have tasty flesh. The current level of offtake is unclear.

It is also used as a bait fish by recreational anglers targeting piscivorous species.

This species is nationally-protected in Croatia. No specific conservation management plan exists, but parts of its range are located within protected areas. Among these, Hutovo Blato and the Neretva Delta are included in the Ramsar Convention on Wetlands and a few sites are listed in the European Union's Natura 2000 network. A new, ostensibly more sustainable, management policy was implemented in the Hutovo Blato basin following a European Union-funded LIFE project which ran from 2000-2002.

The proposed hydropower developments in the Neretva and Trebišnjica rivers have been opposed by local communities and several NGOs, leading to the publication of various news articles, reports, research projects and dissemination events, e.g., Neretva Science Week (July 2022).

A deeper understanding of this species' population trend, abundance, distribution and life history would likely prove useful in the establishment of future management efforts and priority conservation sites.