Umbra krameri WALBAUM, 1792.

Among the 227 species of freshwater fish found in Europe, 200 are regarded as native and 27 as introduced. In the Bern Convention are now included 122 species: 118 as protected fauna species, and 4 as strictly protected species ( Acipenser naccarii - Adriatic strugeon, alencia hispanica - Samarugo, Zingel asper - Asper and Umbra krameri - Eurpean mudminnow ).
The European mudminnow is the only native of five umbrid species confined to the drainga basins of the Danube, Prut and Dniester. It is one of the most endangered species of the original Danubian fish fauna. Threats ( especially in Croatia ) that might lead to the extincion of this small fish are thoseoriented to disappearance of its habitats describe as marsh land and swamp regions:
· Destruction of natural habitats by land - reclamation measures and stream regulation.
· Use of ponds, oxbow lakes, swamps and other "closed" water bodies as waste disposal sites.
· Uncontrolled or intensive use of biocides and other chemicals for different agricultural purposes, especially on private lands.
· Timber harvest and progressive soil erosion, sedimentation and euthrophication.
· Possible realization of plans for series of hydroelectric power plants to be constructed on the Mura River (where Umbra krameri was found in Croatia ).


SYSTEMATIC:
Subphylyum: Vertebrata
Superclass: Gnathostomata
Grade: Pisces
Class: Osteichthyes
Subclass: Actinopterygii
Infraclass: Neopterygii
Division: Halecostomi
Subdivision: Teleostei
Infradivision: Euteleostei
Superorder: Protacanthopterygii
Suborder: Esocoidei
Family: Umbridae


DESCRIPTION:
The European mudminnow is a small fish with a total length of 5 to 9 cm, sometimes reaching 11.5 cm. The body mass is 5 to 8 g, 27 g at most. It has an elongated, cylindrical bodyshape which is slightly compressed laterally. The males are usually smaller and more slender than the females. The mouth is relatively large and slightly directed upwards. The upper jaw is shorter than the lower one and extends to the middle of the eye. The upper jaw and the tongue are without teeth. Fine, villiform teeth can be found on the lower maxillary, premaxillary, vomer, and palatines. The whole body and the head except the snout and chin are covered by large cycloid scales. The lateral line is missing, along decide 31-36 scales are found, above and bellow there are 5-7 rows of scales. The color of the mudminnow is usually dark brown on the back and lightgrey, almost white on the belly. Differently shaped black spots are distributed irregularly over the body. A light stripe extends laterally from just behind the opercles to the caudal peduncle. Black bands of elongated, regularly positioned spots are found in the dorsal and caudal fin. The dorsal fin is situated in the second half of the body, originates directly above the origin of the pelvics, and extands to the origin of the anal fin. Its rays are equally long so that the fin appears almost rectangular. The unpaired fins, especially the caudal fin, are rounded.

HABITAT:
In general the areas where the species can be found are described as marsh land and swamp regions. It can be found in densely overgrown parts of larger waters, but mostly in smaller, highly structured waters like abandoned oxbow lakes, diches and ponds. An obvious similarity of all habitats described is the rich structure provided by plants characteristic for marsh and swamp areas.

FEEDING HABITS:
Young mudminnows feed mainly on small crustaceans like ostracods and cyclopoids, and chironomid larvae. At the end of first summer the switch to larger food items. Mostly benthic food is found in their guts. But also food from the surface and mid- water like water- beetles and other insects is taken.

LONGEVITY:
The maximum age of the mudminnows can be 5 to 6 years of age.

Author: Davor Zanella, Sandra Kraljeviæ- students at the University of
Zagreb- Faculty of science, division of biology