Italian bleak  (Alburnus albidus)

The Italian bleak is classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

This small freshwater fish, once a common inhabitant of rivers in southern Italy, has been the victim of a drastic population decline in recent years. The Italian bleak (Alburnus albidus) has a spindle-shaped body with a slight protrusion behind the head. It is a dark metallic colour on the upperparts and silvery-white on the underside, with yellow eyes and grey fins. The tail is forked with sharpened lobes. Different populations of this species may differ slightly in size and colouration (4).

The Italian bleak differs from the closely related common bleak (Alburnus alburnus) by its rounded mouth and less prominent jaw (4).

The Italian bleak is endemic to southern Italy. Its natural range stretches from the Voltumo to Alento Rivers in the west, and from the Trigno to Basento Rivers in the east. Introduced populations are found in the Mingardo, Bussento, Lao, and Savuto Rivers (1) (5).

The Italian bleak inhabits well-oxygenated, clear, mountainous and hilly streams, as well as small rivers(5). It usually populates the middle and lower parts of a river, where it is often the dominant species together with the European chub (Squalius cephalus) and the common barbel (Barbus barbus) (4).

An omnivorous fish, the Italian bleak’s diet is strongly influenced by the changing of the seasons. During spring the Italian bleak feeds on drifting insects or invertebrates that have fallen onto water’s surface (5), in summer it tends to eat freshwater green algae, while in winter its diet is largely composed of organic debris (4).

Reproduction takes place late in the spring, when the female lays eggs between small stones close to the riverbank (4).

The population of the Italian bleak has been reduced by 50 percent in the past 10 years, mainly due to the introduction of Rutilus rubilio (South European roach), and by the decline in habitat quality caused by the creation of canals and draining of water courses (1). Hybridization with Leuciscus cephalus (European chub) is also a threat to this little fish (1) (6).

Climate change also poses a long-term threat to the Italian bleak (1), as an increase in global temperatures is predicted to result in a decrease in freshwater in the Mediterranean basin region (8).

The Italian bleak is protected in Europe under Appendix III of the Convention on the Conservation of European Wildlife and Natural Habitats (also known as the Bern Convention) (7). Efforts are being made to protect the habitat of this fish by creating special conservation zones. Educating fishermen, who sometimes uses the Italian bleak as bait, is another important action being undertaken by Italian authorities (4).

To learn about efforts to protect freshwater ecosystems see:

• The Nature Conservancy:
  http://www.nature.org/initiatives/freshwater
• Conservation International:
  http://www.conservation.org/learn/freshwater
• Zoological Society of London:
  http://www.zsl.org/conservation/regions/uk-europe/fish-net,1334,AR.html