Abstract

After the first phocine distemper virus (PDV) epizootic in Germany in 1988 it was recognized that there was little knowledge on marine mammals in German waters. Hereupon, since 1989/90 the state of Schleswig-Holstein, Germany, namely the Ministry of Environment and the Supreme Hunting Administration, has financed a very well structured and successful marine mammal stranding network. Schleswig-Holstein is the only state in Germany which has both North and Baltic Sea coasts (Figure 1). Another important feature of the state is the Wadden Sea on the North Sea side with its tidal amplitude. The stranding network also includes the only German offshore island "Helgoland" (North Sea). At the moment there are only three indigenous marine mammals in German waters: harbor seal (Phoca vitulina), gray seal (Halichoerus grypus), and harbor porpoise (Phocoena phocoena). Only the latter is native to the German Baltic waters. During the years, a vast variety of other marine mammals have visited German coasts but mostly ended up deceased and washed ashore (e.g., beaked whales, sperm whales, humpback whales, fin whales, ringed seal, hooded seal). All marine mammals are reported and/or transported to the Research and Technology Center Westcoast (FTZ) in Büsum, an affiliation of the University of Kiel, Germany. Not to bring every single dead animal to the institute, a chain of freezers were positioned at several places along the coasts. Park rangers and seal hunters are appointed to patrol the beaches and coastlines to look out for sick or dead pinnipeds or cetaceans (Figure 2). This ensures a comprehensive monitoring throughout the whole year.

At the FTZ the animals are necropsied and a number of further investigations are carried out (e.g., virology, bacteriology, toxicology, histology, parasitology). The FTZ is in close relationship with many other national and international institutions, providing samples for numerous projects (e.g., University of Liège, Belgium; Alterra, Univ. Wageningen, Netherlands; Zoological Society of London, England; Marine Station, Poland; Swedish Museum of Natural History, Stockholm, Sweden). Results of the examinations are directly relevant for political decisions and are presented at different international meetings, such as ASCOBANS, ICES, and IWC. The stranding network also helps fulfill national and international agreements and guidelines. Furthermore, analyses resulting from the necropsies are presented at international conferences (e.g., IAAAM, EAAM, SMM, ECS) and are published in international peer-reviewed journals. Overall about 3,000 whales (1990-2009) and 2,000 seals (1996-2009) were examined in course of the stranding network. In the last year alone, about 370 porpoises and seals were investigated at the FTZ. During such a long period of time many interesting cases have been detected.

The stranding network also includes the care-taking of orphaned pups. On the numerous frequented beaches, most of the German harbor seals are born during pupping season in summer. Especially from May to July (with a peak in mid June), the seal hunters and park rangers are called several times a day to check on a pup. If it turns out to be left alone by its mother, the pup is brought to the Seal Center Friedrichskoog where it is reared (~ 60-80 p.a.). Before they are admitted to the center, however, they have to pass a general health test (weight >7.5 kg, hemogram, check of umbilicus, joints, oral mucosa, etc.). After 2 ½-3 months of rehabilitation, they are released again into the Wadden Sea near a sandbank, which is a known haul-out site for seals. The seal center is open to the public and trained staff brings awareness to the problem of orphaned pups. Theses were written on numerous subjects about their development. Therefore, the pups fulfill important features to the general public but also to science.

Figure 1 Map of Germany (left) and North and Baltic Sea coastlines of Schleswig-Holstein, Germany (right).

Figure 2 Map of Schleswig-Holstein with stations of freezers and seal hunters.

Acknowledgements

The authors would like to thank the entire team of park rangers and seal hunters for their invaluable time effort and information exchange. Also many thanks go to Dr. Jörg Driver and the staff of the Seal Center Friedrichskoog. The authors wish to thank all people helping in the necropsies.