Abstract: The brook lamprey (Lampetra planeri) populations of the upper Danube Basin within Baden-Württemberg (Germany) were studied between 1989 and 1994. 10 recently extinct and 40 currently existing populations were documented and major factors threatening their existence were identified. Among these factors, physical obstacles forming effective migration barriers often confine populations to isolated reaches of a river without the possibility of (genetic) exchange with other populations further downstream or within the Danube itself. Further physical disturbances adversely affecting lamprey habitat include river channelization, river bank reconstruction and sediment removal. As evidenced in the Lauchert River, sediment removal was the direct cause of mortality for substantial numbers of lampreys. The contamination of waters with organic wastes from agricultural use, input of nutrients from diffuse run-off or point sources, such as water treatment plants, and accidental toxic spills are generally of less importance, but nevertheless represent significant threats for individual lamprey populations. Finally, heavy stocking of catchable size salmonids, particularly in unsuitable rivers, can lead to increased predation pressure on adult lampreys and, therefore, reduced population fecundity. The relative importance of the different factors that put lamprey populations at risk are quantified and discussed in the context of feasible conservation measures.Keywords:
Author(s): Kappus, B., Jansen, W., Fok, P. & Rahmann, H.
Title: Threatened lamprey (Lampetra planeri) populations of the Danube Basin within Baden-Württemberg, Germany
Publication date: 1995-10-30
brook lamprey, Lampetra planeri, habitat alteration, water quality, population extinction, Upper Danube BasinJournal: Miscellanea zoologica hungaricaJournal abbreviation: Miscnea zool. hung.ISSN: 0230-9017Publisher: Hungarian Natural History Museum, BudapestEditor(s): Forró, L.
, Bankovics, A., Demeter, A., Korsós, Z., Murai, É., Pintér, L. & Matskási, I.