''Zingel asper'', also known as the Rhone streber, is a
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of freshwater
ray-finned fish
Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...
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 nearly 250 ...
that is at a high risk of becoming
extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
due to
habitat destruction
Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
and
pollution
Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...
. 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 in the
Rhône
The Rhône ( , ; Occitan language, Occitan: ''Ròse''; Franco-Provençal, Arpitan: ''Rôno'') is a major river in France and Switzerland, rising in the Alps and flowing west and south through Lake Geneva and Southeastern France before dischargi ...
basin in
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
and
Switzerland
Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. 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 advance ...
Hydropsychidae
The Hydropsychidae are a Family (biology), family-level taxon consisting of net-spinning Trichoptera, caddisflies. Hydropsychids are common among much of the world's streams, and a few species occupy the shorelines of freshwater lakes. Larvae o ...
), and varies by season, with flies consumed primarily during the winter.
''Zingel asper'' can be found in 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. ''Zingel asper'' lives in habitats similar to that of the
loach
Loaches are ray-finned fishes of the suborder Cobitoidei. They are freshwater, benthic (bottom-dwelling) fish found in rivers and creeks throughout Eurasia and North Africa, northern Africa. Loaches are among the most diverse groups of fish; the ...
common minnow
''Phoxinus phoxinus'' (known colloquially as the Eurasian minnow, minnow, Channel minnow, or common minnow) is a species of freshwater ray-finned fish belonging to the family Leuciscidae, which includes the daces, minnows and related fishes. It i ...
(''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
Substrate may refer to:
Physical layers
*Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached
** Substrate (aquatic environment), the earthy material that exi ...
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 (, ; ; ) 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) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
rates this species as being "
Endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
". 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.