The Mediterranean Barbel (Barbus meridionalis) is endemic to Europe, where it is native to a series of river systems in southern France and northeastern Spain. The species does not approach the range size thresholds for Vulnerable under Criterion B1 (extent of occurrence (EOO) < 20,000 km²) or D2, and Criterion B2 is precluded by its uncertain area of occupancy (AOO). The population size is believed to exceed mature 10,000 individuals, hence it does not approach the thresholds for Criteria C or D. There exists no quantitative analysis which would permit application of Criterion E.

Although no range-wide population trend data are available, significant site-scale declines have occurred within the last 20-30 years, and a suspected ongoing reduction based on declining habitat quality and the effects of introduced taxa could meet the threshold for Vulnerable under Criterion A2 (≥ 30% in the past ten years). As a result of this data uncertainty, Least Concern and Vulnerable are equally plausible Red List categories for the present assessment, and this species is assessed as Near Threatened (A2ce) on the basis of a population decline over the past three generations that at least approaches the threshold for a threatened category, driven by an estimated continuing decline in habitat quality, based on the impacts from invasive alien species and pollution.

This species is native to a series of river systems in southern France and northeastern Spain, where its range extends southward from the Rhône River to the Llobregat River. It is naturally absent from the upper Rhône catchment.

In Spain it has been introduced to the Llobregat River, and its presence in the Garonne River, France, is probably a result of translocation during the 17^th century.

This species' population size is unknown, but is believed to exceed the minimum threshold for Red List criteria (< 10,000 mature individuals). The current population trend has not been quantified, and the number of subpopulations is unclear. However, a number of site-scale reductions in abundance have reportedly occurred in Catalonia, Spain, since the turn of the 21^st century, and this pattern is suspected to be ongoing based on declining habitat quality (see 'Threats').

This benthic species exhibits a preference for the middle and upper reaches of rivers and streams, where it is typically associated with habitats characterised by coarse stony substrata, often with exposed bedrock and abundant riparian vegetation.

Some subpopulations inhabit temporal rivers, which naturally dry out during the summer and other drought periods. The abundance of resident fish is significantly reduced at such times, but some individuals survive in remnant pools or short perennial reaches. This species' life history has not been extensively studied. The annual reproductive period extends from May to June, during which period nuptial male individuals develop a series of tubercles on the body.

It hybridises naturally with the Iberian Redfin Barbel (Barbus haasi) in the Besós River, Spain, and with the Common Barbel (Barbus barbus) in the Hérault River, France.

This species is threatened by river regulation and other forms of anthropogenic habitat degradation. In particular, the construction of dams, sills, weirs and other barriers throughout its range has severely altered natural flow and sedimentation regimes, fragmented subpopulations, and reduced the extent of suitable habitat for all life stages. Hydroelectric schemes have created 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, changes in land use, and the removal of riparian vegetation has increased the accumulation of fine sediments at some sites, plausibly impairing the hatching and survival rates of eggs and larvae.

The quality of available habitat has been further diminished by bank stabilisation, channelisation and other efforts to enhance flood protection or exploit water resources for irrigated agriculture. Unregulated water abstraction may constitute a particular threat in temporal river stretches during the summer, where native fishes are often confined to small refugia (see 'Habitat and Ecology').

This species is also threatened by diffuse and point source agricultural, domestic and industrial pollution, which has at some locations reduced the extent and quality of habitat due to eutrophication or discharge of toxic substances. Pollution can be particularly impactful when discharge is reduced during the summer.

In the Argens River, France, it may also be threatened by introgressive hybridisation with the congeneric but non-native Common Barbel (Barbus barbus), which entered the river during the 1980s via man-made canals connecting it to the Rhône River system. There is also a potential risk of increased transmission of metazoan parasites to the Mediterranean Barbel through hybrid individuals. Hybridisation between these two species has also been detected elsewhere, e.g., in the Hérault River, but is understood to be a natural phenomenon.

The remnant pools in which some Mediterranean Barbel individuals typically spend the summer favour colonisation by non-native fishes and crustaceans such as the Pumpkinseed (Lepomis gibbosus), Largemouth Bass (Micropterus salmoides) and Eastern Mosquitofish (Gambusia holbrooki), plus the Red Swamp Crayfish (Procambarus clarkii), all of which prefer lentic conditions and are known to exert negative effects on native species through predation and/or resource competition.

The negative impact of some threats could plausibly be exacerbated by increasingly rapid climate change in the Mediterranean region. Some areas in the Spanish region of Catalonia received no rainfall at all between 2020-2023, leading to an extended period of significantly decreased river discharge throughout the southern part of this species' range.

This species is not used or traded.

This species is included in Appendix III of the Bern Convention plus Annexes II and V of the European Union Habitats Directive. It is nationally-protected in France, where it is prohibited to damage sites important for its feeding, growth or reproduction (Arrêté du 8/12/1988, Arrêté du 23/04/2008). It occurs within the boundaries of various protected areas, some of which are included in the European Union's Natura 2000 network.

It has been assessed as Near Threatened and Vulnerable for the most recent National Red Lists of France (2019) and Spain (2002), respectively.

Although not targeted by any specific conservation management plan, some Spanish subpopulations may have benefitted from recent efforts to increase connectivity through installation of fishways on existing dams and other barriers.