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

The Prespa Barbel is native to the Lake Prespa transboundary basin, which is shared by Albania, the Republic of North Macedonia and Greece. It has a restricted range (extent of occurrence (EOO) c. 17,000-24,812 km²), based on expert consensus and the maximum extent of the river catchments where the species is present. The lower value meets the threshold for Vulnerable under Criterion B1 (< 20,000 km²) and is considered to be the more plausible estimate. . The extent and quality of habitat are 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 this species demonstrates extreme fluctuations. No explicit area of occupancy (AOO), population size or trend data are available and the probability of extinction has not been quantified, so the remaining criteria are presently inapplicable. 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. 6,767 km². It is present at four locations where habitat quality is estimated to be declining, and is assessed as Vulnerable under Criterion B (B1ab(iii)).

This species is native to the Lake Prespa (sq. Liqeni i Prespës; mk. Преспанско Езеро; el. λίμνη Πρέσπα) transboundary basin, which is shared by Albania, the Republic of North Macedonia and Greece. In Greece it is present at four locations, comprising lakes Greater Prespa and Lesser Prespa, the Agios Germanos River in the Greater Prespa basin, and the upper Vjosa River.

It is also present in the Shkumbin, Seman, Dukati and Borsh river systems in central and southern Albania, and the Vjosa (el. Αώος/Aoös) River, which flows from Greece to Albania.

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

In the Prespa Lakes basin, its abundance is understood to have declined by an undetermined extent since the late 20^th century (see 'Threats').

The Prespa Lakes basin lies at 850 metres AMSL and is a hotspot for endemic biodiversity, including freshwater fishes, and migratory birds. It comprises two relatively shallow interlinked lakes; the larger Greater Prespa (el. Μεγάλη Πρέσπα; mk. Преспанско Езеро; sq. Liqeni i Prespës së Madhe) and Lesser Prespa (el. Μικρή Πρέσπα; mk. Мало Преспанско Езеро; sq. Prespa e Vogël), which are separated by a narrow strip of alluvial land. The catchment is fed solely by precipitation and snowmelt. It partially drains to nearby Lake Ohrid (sq. Liqeni i Ohrit; mk. Охридско Езеро), and by extension the Drin (sq. Drini; mk. Дрим) River system, via subsurface karstic conduits.

Prespa Barbel subpopulations occurring in these lakes mostly inhabit littoral zones with substrata of stones, gravel or sand, which they also use for spawning between April and June. In Greater Prespa there are additional spawning grounds in a number of tributary streams, into which the fish migrate during spring. Fluvial subpopulations are most abundant in stream and river reaches with clean, flowing, well-oxygenated water and substrata of gravel, cobbles and boulders. This species is benthic and feeds primarily on aquatic invertebrates such as amphipods.

The Prespa Lakes have been partially modified. They are connected by a man-made channel excavated through the alluvial isthmus which separates them, on which a controllable sluice is installed and was reconstructed in 2004. In addition, a minor natural outflow from the affluent Agios Germanos river delta to Lesser Prespa was blocked during the 1930s and has not been restored, reducing the volume of water that flows into the lake. In Albania, Lesser Prespa was for a number of years artificially connected to the Devoll River via the so-called Prespa Canal Scheme in order to abstract water for irrigation purposes, but the project was abandoned and the canal filled in during the early 2000s. During the period that the canal was open, sedimentation in the southern portion of Lesser Prespa increased drastically, leading to a pronounced reduction in water depth and notable expansion of reedbeds.

Ongoing water abstraction for agricultural and domestic use takes place throughout the Prespa basin. Water abstraction has been cited as the central cause for the continued diminishing water level in Greater Prespa, which has receded by at least eight metres since the mid-20th century. However, climate change is also a primary driver, with a significant decrease in discharge, winter precipitation and snowfall observed since the 1960s. The situation is so drastic that the sluice gate between the lakes has to be kept closed at all times in order to maintain the water level in Lesser Prespa, which is now located at a higher altitude than Greater Prespa and would otherwise drain into it. The reduction in water volume, coupled with an increase in nutrients, toxic substances and solid materials (including plastics) entering the lakes from surrounding farmland, industry (small-scale food processing, poultry farming, textiles, metal and wood processing, civil construction, ceramics and chemicals), illegal landfills, fly-tipping and untreated domestic wastewater has resulted in escalating eutrophication and a reduction in the extent and quality of littoral spawning and nursery habitat for native fishes. This is particularly evident in Lesser Prespa, where blooms of toxic cyanobacteria now occur on a regular basis during summer and autumn.

Construction of small dams on streams draining into Greater Prespa has blocked access to some of the Prespa Barbel's traditional spawning grounds, and additional hydroelectric projects are planned. Elsewhere, fluvial Prespa Barbel subpopulations are threatened by the construction of dams and other barriers, which disrupt natural discharge, sediment and temperature regimes while driving habitat fragmentation and the establishment of non-native fish species.

Moreover, no fewer than 13 non-native freshwater fish species have been introduced to the Prespa basin, of which at least six have become established. These include the Topmouth Gudgeon (Pseudorasbora parva), Pumpkinseed (Lepomis gibbosus), Common Carp and European Bitterling (Rhodeus amarus), all of which are considered invasive and can exert detrimental pressures on native freshwater fauna through increased competition, predation or habitat degradation.

Although sometimes cited as such, predation by waterbirds does not constitute a plausible threat to native fishes in the Prespa ecosystem.

In smaller river systems and tributaries excessive water abstraction and pollution from agricultural, domestic and industrial sources are also of concern.

This species is harvested by commercial fishers in the Prespa Lakes, where it is sold to local restaurants or exported to regional wholesalers. Although highly prized, it only comprises a relatively minor component of the Prespa fishery, which is dominated by native Prespa Bleak (Alburnus belvica), Prespa Nase (Chondrostoma prespense) and Dalmatian Roach (Leucos basak), plus introduced Common Carp (Cyprinus domestic strain).

The total number of fishermen in the Prespa basin has declined considerably since the late 20^th century, and most traditional fishing methods have been abandoned since the early 2000s. Fishing sustainability models suggest that the historic level of offtake has been reasonable, while the current level does not constitute a plausible threat.

This species is included (as Barbus spp.) in Annex V of the European Union Habitats Directive. The species has been assessed as Vulnerable under criteria B1ab(ii,iii)+2ab(ii,iii) for the Greece national Red List (Vagenas 2024).

The entire Prespa Lakes basin falls within the limits of the Prespa Park, the first transboundary protected area in the Balkan Peninsula. The park was established in 2000 following a trilateral declaration by the bordering nations in response to environmental concerns regarding the lakes, but was not formalised until 2017. The lakes are also surrounded by four National Parks and two sites within the basin are included in the European Union's Natura 2000 network of protected areas. In addition, both lakes are designated as Wetlands of International Importance by the Ramsar Convention on Wetlands. Since 2005, the Prespa Park Management Body controls the volume of water exiting Lesser Prespa to Greater Prespa by regulating the outflow discharge on the artificial channel connecting the two lakes. The environmental organisation 'Society for the Protection of Prespa' currently coordinates a transboundary environmental monitoring system within the Prespa basin, which includes tri-annual fish surveys.

The European Union co-funded LIFE project 'Prespa Waterbirds' (LIFE15 NAT/GR/000936) ran from 2016-2021 and aimed to contribute to waterbird conservation in Lesser Prespa via a series of actions, including a specific plan to improve "spawning grounds and access for fish species". Specific actions included the clearing of sediment and reedbeds from around the mouths of tributary streams to facilitate the passage of migratory fishes. An earlier LIFE project (LIFE2002 NAT/GR/8494) also targeting bird conservation took place from 2002-2007 and aimed to "increase fish spawning grounds", while the Global Environment Facility project 'Integrated Ecosystem Management in the Prespa Basin in Albania, North Macedonia and Greece' ran from 2006-2011. Furthermore, a LIFE+ Information and Communication Project entitled 'Fish, Fisheries & European Policy' in the Prespa Basin (LIFE09 INF/GR/000319) was funded from 2010-2013 with the objective to "promote the conservation of the threatened endemic and rare fish fauna of the area and the implementation of sustainable fishery practices".

The introduction of non-native species to the Prespa Lakes has been outlawed, and strict annual catch limits are in place for the native fishes of commercial interest. Fishing of any kind is also forbidden during mid-to-late spring, when native fish species spawn. Fly-tipping, disposal or processing of any kind of waste, discharge of untreated waste water, shoreline construction, excavation of sand or gravel, unlicensed use of lake water, uncontrolled cutting of trees and forests, and inappropriate utilisation and burning of pastures have all been prohibited.

In 2023, the entire Vjosa River catchment was designated as Europe's first Wild River National Park. A number of sites in the upper Vjosa, Greece, are additionally included in the European Union's Natura 2000 network.

A deeper understanding of its present distribution, demographics (population size and trend), life history and response to the ongoing threats would likely prove beneficial in the design of any structured management plan.