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

The Neretva Spined Loach is endemic to southeastern Europe, where it has a restricted extent of occurrence (EOO) c. 3,848 km², which meets the threshold for the Endangered category under Criterion B1 (EOO < 5,000 km²). The extent and quality of habitat are estimated to be undergoing continuing decline, but the number of locations is unknown and it is unclear whether the extant subpopulations are severely fragmented. There is no evidence that it 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 currently inapplicable. Therefore, this species is assessed as Near Threatened at the global and European regional scales because it is close to qualifying for Endangered under Criterion B.

In the EU 27 member states, the EOO is c. 180 km² and the area of occupancy (AOO) is c. 20 km², both of which meet the thresholds for the Endangered category under Criterion B (EOO < 5,000 km², AOO < 500 km²). It is present at five locations where the extent and quality of habitat are estimated to be undergoing continuing decline, but 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 (VU°) under Criterion B (B1ab(iii)+2ab(iii)).

This species is endemic to the Neretva River system in the Dinaric Karst region of Croatia and Bosnia and Herzegovina.

Most records pertain to the lower reaches of the river, including channels and lakes (Kuti, Modro Oko) within its delta, plus the Hutovo Blato wetland. It also inhabits the adjacent Trebišnjica River drainage, which is partially connected to the Neretva via subterranean karstic conduits. There are no confirmed records upstream of the city of Mostar, or from isolated plateaus (polje) associated with left-bank tributaries of the river in Bosnia and Herzegovina, e.g., Nevesinjsko, Gatačko, Dabarsko and Fatničko poljes. It is naturally absent from the right-bank Lištica and Trebižat tributary systems, which are somewhat isolated by karstic landscape features and inhabited by congeneric taxa.

This species' global AOO is unclear. In the EU 27 member states (Croatia) the AOO is 20 km², which meets the threshold for the Endangered category (< 500 km²) and approaches the threshold for Critically Endangered (< 10 km²).

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

This small-bodied, benthic species inhabits karstic rivers, wetlands and artificial channels with substrata comprising fine sediments, rocks or gravel, sometimes with dense growth of aquatic vegetation. The Trebišnjica is a spring-fed sinking river which flows through a series of karstic depressions known as poljes. It is partially connected to the Neretva system via subterranean karstic conduits.

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

Like other Cobitis species, it feeds by filtering mouthfuls of fine material through the gills, from which minute organic particles and small benthic organisms are extracted and consumed. It is also a facultative air-breather that makes use of its hindgut as an accessory air-breathing organ. Little is known of its life history, but related species tend to spawn among submerged vegetation, where the eggs are retained until they hatch. Female individuals grow considerably larger than males.

The extent and quality of habitat are estimated to be undergoing continuing decline based on field observations and the identified threats (see 'Threats').

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

In particular, the 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 future plan to divert water from Hutovo Blato for domestic use may further reduce habitat quality. 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 Trebišnjica River system has 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 (see below). 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.

The Trebišnjica system is set to undergo further modification as a result of the ongoing (as of 2023) "Upper Horizons" hydropower strategy, which aims to artificially redirect water from poljes draining to the Buna and Bregava rivers in the lower Neretva watershed to the Bileća reservoir through a cascading series of canals, tunnels and smaller hydroelectric stations. Once complete, the scheme is projected to significantly reduce discharge in the lower Neretva, and drive a range of negative impacts on Hutovo Blato and the river's delta region.

Non-native fish species established in the Neretva system include Common Carp (Cyprinus domestic strain), Prussian Carp (Carassius gibelio), Sunbleak (Leucaspius delineatus), Largemouth Bass (Micropterus salmoides), Pumpkinseed (Lepomis gibbosus), Eurasian Pikeperch (Sander lucioperca), Eurasian Ruffe (Gymnocephalus cernua), Brown Bullhead (Ameiurus nebulosus), and Eastern Mosquitofish (Gambusia holbrooki), all of which are considered invasive and can exert detrimental pressures on native freshwater fauna through increased competition, predation or habitat degradation.

This species is not used or traded.

No specific conservation actions are in place, but this species is included (originally as Cobitis taenia) in Appendix III of the Bern Convention and Annex II of the European Union Habitats Directive.

It is strictly protected at the regional scale in the Republic of Srpska (Bosnia and Herzegovina), and at the national scale in Croatia. The Neretva River Delta is a protected area that is listed in the Ramsar Convention on Wetlands of International Importance (site no. 585), and incorporates six sites included in the European Union's Natura 2000 network. The Neretva Spined Loach is not listed as a target species in any of the latter, which are primarily focused on birds.

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.