Molecular evidence indicates that chub subpopulations inhabiting rivers draining to the Ionian Sea may represent a separate taxon (Lucentini et al. 2014), but they are included here pending a definitive review.

Global and European regional assessment: Least Concern (LC)
EU 27 regional assessment: Least Concern (LC)

Although this species' population trend may be decreasing due to habitat degradation, there is no evidence that the rate of decline approaches the minimum threshold for Vulnerable under Criterion A (≥ 30% over the longer of 10 years or three generations). It does not approach the range thresholds for Vulnerable under Criterion B (extent of occurrence (EOO) < 20,000 km², area of occupancy (AOO) < 2,000 km²) or D2. The population size significantly exceeds 10,000 mature 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.

Therefore, the Italian Chub does not currently meet the thresholds for any Red List criteria, and it is assessed as Least Concern both globally and for the EU 27 member states.

This species is native to the majority of rivers draining the Italian Peninsula and northern Adriatic Sea basin. On the Ligurian/Tyrrhenian slope of Italy its range extends from the Centa River in Liguria to the Noce River in Calabria, and it is also present from the Bradano to the Tacina River in the Ionian Sea basin (but see 'Taxonomic Notes'). In the Adriatic Basin, it occurs northward from the Ofanto River in Apulia, Italy to Istria, Croatia.

The precise extent of its natural range in the Western Balkans is unclear. Molecular analyses have revealed that isolated, putatively native subpopulations inhabit Lake Visovačko (Krka River system) in Croatia, and the Trebišnjica River in Bosnia and Herzegovina. It occurs sympatrically with the congeneric Neretva Chub (Squalius svallize) and a putative undescribed species in the Trebišnjica River, where hybridisation between the three has occurred and there are significant doubts as to which of them are native to the system.

A chub subpopulation inhabiting the Ljuta River in Konavosko polje, Croatia, is currently included in the Neretva Chub assessment for Red List purposes. However, all individuals contain Italian Chub haplotypes as a presumed consequence of past natural hybridisation.

This species' population size is unknown, but it significantly exceeds 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.

Field observations indicate that it remains both common and abundant throughout much of its range, but local declines have been reported in some areas of northern and central Italy, e.g., lowland parts of the Po River system, rivers of Arezzo Province, the Tiber River catchment. There are indications of decline in the Marche region (Foglia, Metauro, Potenza, Chienti, and Tronto rivers).

In the Po River system, studies indicate a general reduction at locations where it was historically among the most abundant native fish species, which is somewhat offset by increasing abundance at certain lotic sites where native salmonids have declined. This pattern is putatively linked to increasing temperatures and the presence of non-native aquatic taxa (see 'Threats'), and could be repeated elsewhere within its range.

This species occurs in rivers and streams with a diverse range of channel morphology and flow regimes, although it tends to be most abundant in the lower and middle reaches of medium-to-large channels and tributaries. It also inhabits lowland and perialpine fluvial lakes, and has colonised a number of artificial reservoirs and drainage canals at locations where there is access to suitable spawning habitat (but see 'Threats').

It feeds largely on invertebrates, but also consumes organic detritus, plant material, amphibian larvae and smaller fishes.

The maximum recorded lifespan is 15 years, with male individuals reaching sexual maturity at age 2-3+ and females at 2-5+. The annual reproductive period extends from March to July, but may commence later and continue until July or August at higher altitudes. This species is a fractional, polygamous spawner, and older individuals mostly spawn earlier in the season. Spawning behaviour itself is characterised by mature adults migrating to specific upstream sites comprising beds of well-washed gravel or other coarse substrata in shallow, fast-flowing water. However, some subpopulations spawn in floodplains, close to the banks of lowland rivers or along lake shorelines. Males often congregate in the vicinity of spawning sites prior to the arrival of females.

In central Italy, it is present in many intermittent streams and rivers characterised by a Mediterranean hydrological regime with significant inter- and intra-annual variations in discharge. Periods of flooding during the winter and early spring are followed by drought events extending from summer and early autumn (typically July-October), during which extensive river and stream reaches are dewatered and reduced to a series of isolated pools which function as refugia for native fishes. During dryer years, large parts of these systems may be completely dessicated, and site-scale abundance can fluctuate considerably. Resident subpopulations exhibit traits typical of freshwater fishes inhabiting unstable environments, including faster growth, earlier maturity and an extended reproductive period compared with those occupying perennial systems. Female individuals also tend to produce only a single batch of eggs per year, which is at odds with the batch-spawning strategy usually observed in this species.

At some locations this species naturally hybridises with the Italian Bleak (Alburnus arborella) or Southern Italian Bleak (Alburnus albidus).

This species is plausibly threatened by river regulation and other forms of anthropogenic habitat modification, although it is reportedly adaptable to moderately degraded conditions. Nevertheless, the construction of large dams plus smaller weirs and other barriers throughout its range has severely altered natural flow and sedimentation regimes, blocked migration routes, fragmented subpopulations, and reduced the extent of suitable habitat for all life stages. Hydroelectric dams 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 accumulation of fine sediments at some spawning 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 to this species' upstream spawning and nursery sites, some of which may also have been damaged by the industrial extraction of riverine gravel or other sediments for urban development.

This species is also exposed to diffuse and point source agricultural, domestic and industrial pollution, which has reduced the extent and quality of habitat at some locations due to eutrophication or discharge of toxic substances. Pollution can be particularly impactful when discharge is reduced during the summer, especially in temporal rivers where native fishes are often confined to small refugia (see 'Habitat and Ecology').

Non-native fish species established within the Italian Chub's range include Pumpkinseed (Lepomis gibbosus), Largemouth Bass (Micropterus salmoides), Eurasian Perch (Perca fluviatilis), Eurasian Pikeperch (Sander lucioperca), Common Bream (Abramis brama), Common Roach (Rutilus rutilus), Goldfish (Carassius auratus), Crucian Carp (Carassius carassius), Common Carp (Cyprinus domestic strain), Topmouth Gudgeon (Pseudorasbora parva), Black Bullhead (Ameiurus melas), Wels Catfish (Silurus glanis), Brown Trout (Salmo trutta) and Rainbow Trout (Onchorhyncus mykiss), all of which are considered invasive and can exert detrimental pressures on native freshwater fauna through increased competition, predation or habitat degradation. Native fish species have been completely displaced by non-native communities in some parts of the Po River system.

Some subpopulations may also be threatened by introgressive hybridisation with the congeneric European Chub (Squalius cephalus), e.g., in rivers of western-central Italy and some Alpine tributaries of the Po River. The extent to which this has occurred has not been investigated anywhere within its range.

The negative impact of some threats could plausibly be exacerbated by increasingly rapid climate change, which is already driving extended periods of drought in the Mediterranean region.

This species is sometimes targeted by recreational anglers, but is not otherwise used or traded.

This species was assessed as Vulnerable for the most recent iterations of the Swiss National Red List of Freshwater Fishes and Cyclostomes (2022) and Croatian Red Book of Freshwater Fish (2006), and Least Concern for the Red List of Italian Vertebrates (2022).

It occurs within the boundaries of various protected areas throughout its range, including a number of national parks and sites included in the European Union's Natura 2000 network.

Some subpopulations may have benefitted from improvements in habitat and water quality associated with implementation of the European Union Water Framework Directive 2000/60/EC.

Future research should ideally involve an appraisal of non-native European Chub within the Italian Chub's range, particularly in areas where intensive stocking has occurred in the past and introgressive hybridisation might be taking place. This species' native range in the Western Balkans is also in need of confirmation.