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SKUKRAINIAN BROOK LAMPREY
The ukrainian brook lamprey needs rivers with a natural flow regime and morphology to prosper. River regulations lead to destruction of suitable habitats for the brook lamprey. Populations on Rudava, Morava and Danube are being monitored.
In the course of this project several habitat improvements, eg removal of barriers, are planned on pilot river stretches.
CHARACTERISTICS
These animals do not belong to the bonefish, but to the jawless ones. Beside the jaw, they also lack the paired fins. Characteristic for all lampreys is also the existence of seven roundish gill-openings behind the eye. Instead of a jaw, lampreys possess a mouth plate, which is occupied with numerous teeth, whose number, arrangement and form can be consulted for determination of the species.
The Ukrainian brook lamprey has a total length of up to 22 cm, most animals become about 18 cm long.
DISTRIBUTION
The Ukrainian brook lamprey occurs in the catchment area of the Danube, it needs clean, rapidly flowing waters in higher altitudes. The species is relatively widespread in Eastern Europe. It is also native to the northern catchment area of the Black Sea - from the Danube to the Kuban.
ENDANGERING AND PROTECTION STATUS
As filtering animals, they are particularly sensitive to water pollution. Due to their very special life cycle, this species has to endure serious interventions in our waters. Especially smaller streams, which represent the preferred habitat of these animals, are degraded by the use of hydropower or by the construction of bank protections. The fine sandy, loose sediment that the larvae need for their development is missing in most streams, so that Ukrainian brook lampreys only occur in a few Austrian waters and are listed on the Red List of Endangered Species (Directive 92/42/EEC Annex II).
WAY OF LIFE
Unlike related species from the sea, the Ukrainian brook lamprey does not live parasitically, but has a very unusual life cycle: during the spawning season between April and May, the reproductive animals gather in groups on rapidly overflowing gravel banks, where the males dig spawn pits. The females lay their eggs in these pits, which are then fertilized by the males. A perennial larval phase takes place on the hatch, which the small larvae (also called Querder) spend blindly in fine sediment and filter food out of the water. Only after reaching sexual maturity, functional eyes, a mouth opening and sexual organs are formed. From this point on, the larval phase is over, the digestive system is reduced and the animals stop eating. The last step in their life is reproduction, where they die immediately after.
SPECIAL
The larvae of the river lampreys live for many years buried in sandbanks and feed by filtering organic particles or diatoms out of the water. Only in the autumn of their penultimate year of life do the transverse lambs turn into adult lampreys.