The Caspian kutum (''Rutilus kutum'') or Caspian white fish is a species of

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 ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Leuciscidae Leuciscidae is a family of freshwater ray-finned fishes, formerly classified as a subfamily of the Cyprinidae, which contains the true minnows. Members of the Old World (OW) clade of minnows within this subfamily are known as European minnow ...

, (related to the daces and Eurasian minnows). It lives in the

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuary ...

habitats of the

Caspian Sea The Caspian Sea is the world's largest inland body of water, described as the List of lakes by area, world's largest lake and usually referred to as a full-fledged sea. An endorheic basin, it lies between Europe and Asia: east of the Caucasus, ...

and its freshwater tributaries. It is typically a medium-sized fish, reaching 45–55 cm in length, rarely 70 cm, and weighing up to 4.00 kg, rarely 5.00 kg. It used to be very common and was harvested commercially. The population seems to have collapsed due to

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...

and

marine pollution Marine pollution occurs when substances used or spread by humans, such as industrial waste, industrial, agricultural pollution, agricultural, and municipal solid waste, residential waste; particle (ecology), particles; noise; excess carbon dioxi ...

. Its flesh and

roe Roe, ( ) or hard roe, is the fully ripe internal egg masses in the ovaries, or the released external egg masses, of fish and certain marine animals such as shrimp, scallop, sea urchins and squid. As a seafood, roe is used both as a cooking, c ...

are enjoyed as food, and highly prized in the

Gilan Gilan Province () is one of the 31 provinces of Iran, in the northwest of the country and southwest of the Caspian Sea. Its capital is the city of Rasht. The province lies along the Caspian Sea, in Iran's Region 3, west of the province of ...

and

Mazandaran Mazandaran Province (; ) is one of the 31 provinces of Iran. Its capital is the city of Sari, Iran, Sari. Located along the southern coast of the Caspian Sea and in the adjacent Central Alborz mountain range and Hyrcanian forests, it is border ...

provinces in

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

Taxonomy

The Caspian kutum was first formally described in 1901 as ''Leuciscus frisii kutum'' by

Sergei Nikolaevich Kamensky Sergius is a male given name of Ancient Roman origin after the name of the Latin ''gens'' Sergia or Sergii of regal and republican ages. It is a common Christian name, in honour of Saint Sergius, or in Kyivan Rus', of Sergius of the Holy Caves ...

with its type locality given as the southern Caspian Sea and its tributaries. This species is now classified within the genus ''

Rutilus ''Rutilus'', commonly known as roaches, is a genus of freshwater ray-finned fish belonging to the family Leuciscidae, which includes the daces, Eurasian minnows and related fishes. This genus is a widely distributed lineage of leuciscids and r ...

'' in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Leuciscinae Leuciscinae is a subfamily of freshwater Actinopterygii, ray-finned fishes belonging to the Family (biology), family Leuciscidae, which includes the fishes known as daces, chubs, shiners and minnows. The fishes in this subfamily are mainly found i ...

of the family

. However, authorities consider that this species is a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of the Black Sea roach ('' R. frisii'').

Etymology

The Caspian kutum belongs to the genus ''Rutilus'', a name which means "red, golden red and reddish yellow" and is an allusion to the red colour of the fins. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''kutum'' is the

Russian Russian(s) may refer to: *Russians (), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *A citizen of Russia *Russian language, the most widely spoken of the Slavic languages *''The Russians'', a b ...

vernacular name Vernacular is the ordinary, informal, spoken form of language, particularly when perceived as having lower social status or less prestige than standard language, which is more codified, institutionally promoted, literary, or formal. More n ...

for this species. The fish is also called Caspian white fish and is known as ''kutum'' in Russian, ''kütüm'' in Azerbaijani, and ''māhi sefid'' in

Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples ** Persian language, an Iranian language of the ...

Description

The Caspian kutum is very similar to the Black Sea roach. It can attain a length of , rarely up to and a weight of , rarely .

Distribution

The Caspian kutum is found along the western and southern coast of the Caspian Sea between Kura to Gorgan Bay, it has been

extirpated Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a chan ...

from the

Volga The Volga (, ) is the longest river in Europe and the longest endorheic basin river in the world. Situated in Russia, it flows through Central Russia to Southern Russia and into the Caspian Sea. The Volga has a length of , and a catchment ...

Biology

The Caspian kutum are predators of benthic organisms, mostly molluscs and other aquatic invertebrates such as insect larvae and crustaceans. They are sexually mature from 4 years old and may live as long as 12 years. They begin their

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

migration from the Caspian Sea into rivers when the water temperature reaches 9–10°C, typically in mid to late February. The spawning migration peaks from mid-March to early April when the water is at 12.3–12.6°C. The eggs are laid in

reed Reed or Reeds may refer to: Science, technology, biology, and medicine * Reed bird (disambiguation) * Reed pen, writing implement in use since ancient times * Reed (plant), one of several tall, grass-like wetland plants of the order Poales * Re ...

s and among

water lilies ''Water Lilies'' ( ) is a series of approximately 250 oil paintings by French Impressionist Claude Monet (1840–1926). The paintings depict his flower garden at his home in Giverny, and were the main focus of his artistic production during ...

at the outflows of rivers when the temperature reaches 13–15°C in late March to mid April. The fecundity of these fishes is dependant on size and varies between 30,000 and 300,000 eggs per female. From mid-May the larvae start a slow migrationtowards the Caspian Sea.

Fishing

The Caspian kutum is an inportant target for fisheries, particularly in the southern Caspian Sea where the stocks are supported by aquaculture and releases.

References

{{Taxonbar, from=Q2637892 Fish described in 1901 Fish of Central Asia Fish of Russia Fish of the Caspian Sea kutum