L. Forró szerk.: Miscellanea Zoologica Hungarica 10. 1995 (Budapest, 1995)

Kappus, B., Jansen, W. , Fok, P.; Rahmann, H.: Threatened lamprey (Lampetra planeri) populations of the Danube Basin within Baden-Württemberg, Germany

Fig. 3. Sediment removal in the Lauchcrt River at Bingen on January 26, 1993 populations within the study area. A further maintenance measure, the periodic removal of sediments, has been documented for 18% of the rivers supporting lampreys. Due to impoundment and channelization, flow dynamics are changed resulting in local accumulation of fine sediments. This silting-up is considered detrimental to flow conditions when rivers are heavily used for electric power generation or for irrigation puiposes. Thus, sediments are often completely removed, sometimes destroying many generations of ammocoetes. The drastic consequences of such measures have been frequently observed during the 4-year study period, affecting the lamprey populations of the Schmiech at Ehingen, the Rohrbach at Furtwangen, the Eisenbach at Hammereisenbach and of the Lauchert at Bingen. An incident occurred on the Lauchert River which provided a drastic example of losses that can occur to a lamprey population. On January 26, 1993 a dredge was seen to remove sediments over a 40 m long section of the Lauchert just upstream of the mill-race in Bingen (Fig. 3). Approximately 15