The Caspian kutum (''Rutilus kutum'') or Caspian white fish is a member of the family
Cyprinidae
Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest verte ...
from
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 estua ...
habitats of the
Caspian Sea
The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...
and from 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 stock), resulting in th ...
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 dioxid ...
. 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, coo ...
are enjoyed as food, and highly prized in the
Gilan and
Mazandaran provinces in
Iran
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
.
Feeding
The main food items are mollusks, shrimp,
amphipod
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descr ...
s, and crabs. Larvae and fry feed on
rotifer
The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals.
They were first described by Rev. John H ...
s, minute forms of
cladoceran
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder (biology), superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms).
Over 1000 species have been recognised s ...
s,
diatom
A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...
algae, and larvae of
copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
s.
Population
Three populations (one autumn and two spring populations) were found in the rivers of Iran; a freshwater form exists in the South Caspian.
Distribution
Caspian kutum is endemic to the Caspian Sea. It is distributed from the mouth of the Volga River up to the
Miankaleh Peninsula. Main aggregations are confined to the southwestern part of the sea adjacent to the
Anzali and Qizilchay Bays. On the eastern coast, it occurs in the
Atrek
The Atrek ( fa, اترک, ku, Etrek, tk, Etrek derýasy), also known as the Attruck, Atrak, and Etrek, is a fast-moving river which begins in the mountains of north-eastern Iran (), and flows westward draining into the south-eastern corner of th ...
estuarine areas and in the Iranian waters.
Behavior
This species lives in small schools in deep water, but spawns in shallow water in the tributaries in April–May. The eggs are laid among weeds or over gravel, and hatch in about 10 days. They become sexually mature in 3–5 years. Resilience of this species is low. Minimum population doubling time is 4.5 – 14 years.
The fish is also called Caspian white fish and Caspian roach, 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 ...
.
[Kuliev Z.M]
''Rutilus friesii kutum'' (Kamensky, 1901)
caspianenvironment.org
See also
*''
Rutilus frisii
''Do not confuse it with another fish called the kutum, ''Rutilus kutum''
''Rutilus frisii'', called the vyrezub, Black Sea roach, or kutum, is a species of fish in the family Cyprinidae, native to the basins of the Black Sea, Sea of Azov, and S ...
''
References
{{Taxonbar, from=Q2637892
Fish described in 1901
Fish of Central Asia
Fish of Russia
Fish of the Caspian Sea
Cyprinid fish of Asia
kutum
Kutum is a town in the Sudanese state of North Darfur. It lies northwest of the state capital, Al-Fashir. The town is located along a wadi and therefore also known as Wadi Kutum. It lies north along the Marrah Mountains; the Kutum volcanic fie ...