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

planeri is considered "endangered" (class 3 on the "Red List"; Bless & Lelek 1984). Table 1 summarizes the status of L. planeri according to the provincial "Red Lists". The median score of 2 designates the brook lamprey as "strongly endangered" and in Thüringen and Bayern the species is threatened by extinction (score of 1). Tablel. Status of the brook lamprey (L. planery) according to the "Red List" for different "Bundesländer" of the Federal Republic of Germany. Categories are: 1 = threatened by extinction; 2 = strongly endangered; 3 = endangered Province Status Source Niedersachsen 2 Gaumert & Kämmereit (1993) Schleswig-Holstein 2 Dehus (1990) MecklenburgVorpommern 3 Winkler et al. (1991) Thüringen 1 Brettfeld ei al. (1993) Nordrhein-Westfalen 3 Borchard et al. (1986) Hessen 2 Meinel et al. (1986) Bayern 1 Bohl (1992) Baden-Württemberg 2 Berg et al. (1989) 2 Bauer & Strubelt (1993) In light of the poor population status throughout its range, the aim of the present paper is to highlight and to evaluate the specific threats to L. planeri populations in the upper Danube area of Baden-Württemberg. There, a unique situation exists in that a) a faunal element originating from the Rhine River system occurs naturally in the Danube River system (Kappus & Rahmann 1994a) and b) L. planeri shows, in addition to typical brook lamprey characteristics, some taxonomic features closely resembling those of Eudontomyzon species (Kappus et al. in press). Therefore, a specific protection scheme is strongly needed. Material and methods The study area encompassed the Danube River system within BadenWürttemberg (47°56'-49°09' N and 8°13'-9°62' E), beginning from headwaters of the rivers Brigach and Breg all the way to the city of Ulm (Fig. 1). Potential lamprey habitats and previously known lamprey populations of the Danube and its tributaries were surveyed regarding the presence or absence of lampreys, their population size and key habitat features (for details see Kappus & Rahmann in press). Of the 50 populations documented in the study area, 10 have not been confirmed within the last 20 years and hence must be considered extinct. The potential threats to the remaining 40 populations were documented through numerous visits to the sites from May 1989 to August 1993. For each site, the relevant biotic and abiotic information were gathered including the degree of morphometrical disturbance, frequency and nature of maintenance measures, presence of horizontal barriers, sewer lines, land use practices, associated fish fauna, and ongoing fisheries management (i.e. stocking) practices. For most sites, questionnaires were distributed to prospective river users, mainly sportfishing clubs.