''Zingel asper'', also known as the Rhone streber, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of freshwater

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

in the family

Percidae The Percidae are a family of ray-finned fish, part of the order Perciformes, which are found in fresh and brackish waters of the Northern Hemisphere. The majority are Nearctic, but there are also Palearctic species. The family contains more than ...

that is at a high risk of becoming

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

due to

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

and pollution. It is endemic to the rivers

Durance The Durance (; ''Durença'' in the Occitan classical norm or ''Durènço'' in the Mistralian norm) is a major river in Southeastern France. A left tributary of the Rhône, it is long. Its drainage basin is .Beaume Beaume may refer to: Several communes in France *La Beaume, arrondissement of Gap, Hautes-Alpes *La Haute-Beaume, arrondissement of Gap, Hautes-Alpes *Beaumes-de-Venise, a canton of the arrondissement of Carpentras, Vaucluse **Muscat de Beaumes-de- ...

in the

Rhône The Rhône ( , ; wae, Rotten ; frp, Rôno ; oc, Ròse ) is a major river in France and Switzerland, rising in the Alps and flowing west and south through Lake Geneva and southeastern France before discharging into the Mediterranean Sea. At Ar ...

basin in France and Switzerland.

Diet and habitat

The asper's diet consists of small insects which include flies (

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

), mayflies (

Baetidae Baetidae is a family of mayfly, mayflies with about 1000 described species in 110 genera distributed worldwide. These are among the smallest of mayflies, adults rarely exceeding 10 mm in length excluding the two long slender tails and someti ...

), and caddisflies (

Hydropsychidae The Hydropsychidae are a family-level taxon consisting of net-spinning caddisflies. Hydropsychids are common among much of the world's streams, and a few species occupy the shorelines of freshwater lakes. Larvae of the hydropsychids construct ...

), and varies by season, with flies consumed primarily during the winter. ''Zingel asper'' can be found in the rivers

. ''Zingel asper'' lives in habitats similar to that of the

loach Loaches are fish of the superfamily Cobitoidea. They are freshwater, benthic (bottom-dwelling) fish found in rivers and creeks throughout Eurasia and northern Africa. Loaches are among the most diverse groups of fish; the 1249 known species of C ...

, '' Cobitis calderoni'', and the

common minnow The Eurasian minnow, minnow, or common minnow (''Phoxinus phoxinus'') is a small species of freshwater fish in the carp family Cyprinidae. It is the type species of genus ''Phoxinus''. It is ubiquitous throughout much of Eurasia, from Britain and ...

(''Phoxinus phoxinus''). It lurks on the stone bottoms of fast-flowing rivers in the day, coming out at night to feed on aquatic vertebrates. It reaches its full maturity after one year, and its length ranges from . Breeding takes place in the deeper parts of riffles. Spawn is deposited on gravel and the eggs stick to the substrate and hatch in about fourteen days. The fertility of ''Zingel asper'' is related to its size.

Status

There are four populations of ''Zingel asper''. The subpopulations in the Durance, with 200 fish per hectare, and the Beaume, with 80 fish per hectare, are relatively stable, but the

Drôme Drôme (; Occitan: ''Droma''; Arpitan: ''Drôma'') is the southernmost department in the Auvergne-Rhône-Alpes region of Southeastern France. Named after the river Drôme, it had a population of 516,762 as of 2019.

population is small and the population in the river

Doubs Doubs (, ; ; frp, Dubs) is a department in the Bourgogne-Franche-Comté region in Eastern France. Named after the river Doubs, it had a population of 543,974 in 2019.IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

rates this species as being " Critically endangered". Its total population is declining and this is thought to be due to the fragmentation of its populations and the modification and destruction of its habitat due to the construction of dams and the pollution of water.

Taxonomy

''Zingel asper'' was first formally described as ''Perca asper'' by Linnaeus in 1758 with its type locality given as the river Rhône.

References

External links

* * {{Taxonbar, from=Q931839 asper Fish described in 1758 Taxa named by Carl Linnaeus Freshwater fish of Europe Fish of Europe