As a group, barbel range from England to Asia and northern Europe to South Africa. There is a great deal of confusion over identification of species and no one source can be taken as fully authoritative.
The southern or Mediterranean barbel lives in small rivers along the French, Spanish and Italian Mediterranean coasts and in parts of the Danube basin and the Balkans. Like all barbel, it has a torpedo-shaped, fully scaled body and two pairs of barbels on its thick lips.
However, the Mediterranean barbel is easily distinguished from the common barbel by the irregular dark blotches on its body and fins. These spots give it a troutlike appearance, which results in its French name ‘barbeau truite’.
The pair of barbels at the back of its lips are slightly longer than those at the front, and it has fewer and larger body scales than those of the common barbel (51-57 in the lateral line as opposed to the common’s 55-65). Also, the Mediterranean fish’s dorsal fin has a smooth — not serrated — rear edge.
Mediterranean barbel are generally smaller than the more common species -due mainly to their shallow and not particularly rich habitat. They only reach about 25cm (10in) in length, whereas the common barbel can reach 90cm (3ft).
However, in the upland reaches of the region’s few larger, fast-flowing rivers the Mediterranean barbel does reasonably well. Unfortunately these areas are threatened by irrigation and the fish (suited to a clean-water existence) is vulnerable to all kinds of pollution.
Even migration downstream to escape these hazards only serves to bring it into competition with larger fish.
Breeding takes place in early summer over gravelly shallows and the eggs, shed among river bed stones, hatch within a few days. The fish uses its barbels to scour the river bed for bottom-living creatures such as insects and freshwater shrimps.
Populations of barbel are isolated in numerous river systems and are genetically different from each other. Even in a moderately small area like the Iberian peninsula (Spain and Portugal), which is bounded by the Pyrenees to the north and by the sea everywhere else, there is still some confusion as to just how many species of barbel actually occur.
One species – the Iberian barbel (Barbus comiza) – is found in the southern and western rivers of Spain and Portugal. (Another very similar subspecies is also found in eastern Spain.) It lives in reservoirs and the slow-flowing reaches of rivers where the water is often warm and clouded with silt. Unlike the Mediterranean barbel, it does not have the dark spots covering its skin. Instead, the Iberian barbel’s most distinctive feature is its longer, flatter snout.
All these populations of barbel are isolated in different water systems and each population is slightly different genetically from the other. These are good reasons why the barbel should be given full protection wherever it occurs.