The Kessler's gudgeon (''Romanogobio kesslerii'') is a European

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 fish in 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 ...

. It is found in the

Danube The Danube ( ; ) is a river that was once a long-standing frontier of the Roman Empire and today connects 10 European countries, running through their territories or being a border. Originating in Germany, the Danube flows southeast for , pa ...

and

Vistula The Vistula (; pl, Wisła, ) is the longest river in Poland and the ninth-longest river in Europe, at in length. The drainage basin, reaching into three other nations, covers , of which is in Poland. The Vistula rises at Barania Góra in ...

drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, t ...

s, including parts of

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, the

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, and

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. It is a small fish of no economic or sporting importance. It was at one time classified as ''Gobio kessleri''. Named in honor of German-Russian zoologist Karl Federovich Kessler (1815-1881).

Description

Kessler's gudgeon is a shallow-bodied, silvery fish with a pointed snout that grows to a length of about or occasionally . It has a pair of barbels by the mouth which help it locate food and which are long enough to reach to the far side of the eye. The throat is scale-less and there are 40 to 42 scales along the

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

. The dorsal fin is made up of eight or nine branched rays.

Distribution and habitat

Kessler's gudgeon is found in rivers and streams in the Danube basin and favours stretches of fast-flowing water with sandy bottoms where the gradient begins to ease off at the foot of the mountains. It is also known from the San River system within the Vistula drainage area.

Biology

Kessler's gudgeon is gregarious and feeds on

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s that lie on the river bed and

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

that drifts past on the current. Adults mature at two to three years of age and spawning takes place in summer. The fish congregate in shallow areas with sandy or gravelly substrates and rise to the surface. The females release their eggs in batches and the males release their

milt Milt is the seminal fluid of fish, mollusks, and certain other water-dwelling animals which reproduce by spraying this fluid, which contains the sperm, onto roe (fish eggs). It can also refer to the sperm sacs or testes that contain the semen. ...

. The eggs gradually sink to the bottom where they stick to stones and weeds.

Status

Kessler's gudgeon is listed as of "

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

" by the

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

. There is some pollution of the rivers in which it lives and economic development on their banks. Its numbers are declining slowly but it is a common species and does not currently warrant a higher level category.

References

* {{Taxonbar, from=Q239875 Romanogobio Freshwater fish of Europe Taxa named by Benedykt Dybowski Fish described in 1862 Taxonomy articles created by Polbot