Common Seals   Information on Dead Seals in 2007 Common Wadden Sea Secretariat, Wilhelmshaven   Status Reports: No. 8 (24.08.2007) / No 7 (15.08.2007) / No.6 (27.7.2007) / No.5 (25.7.2007) / No.4 (24.7.2007) / No.3 (12.7.2007) / No.2 (6.7.2007) / No.1 (25.6.2007) Background Information / Seal Epidemic 2002   Status Report No. 8: Update on the current seal epidemic (24 August 2007)   Up to the 22nd of August more than 90 seals have died along the Swedish west coast up to the Tanum Municipality. The ultimate cause of death was pneumonia in all cases. We get daily reports of single cases in the entire area, which means that the disease is still present in Swedish waters all the way from southern Kattegat and northwards. It was said in the 7th status report that the Swedish Museum of Natural History was awaiting sequencing results from IAH. This is not correct. The tested samples were proved negative for PDV, which means that PDV is not the likely infective agent causing the current seal epidemic. Tero Härkönen, Swedish Museum of Natural History, 24.08.07 Figure: Map with locations of found dead seals. (Download status report No. 8)     Status Report No. 7: Mild epidemic (15 August 2007)   According to Tero Härkönen from the Swedish Museum of Natural History, until 12 August 2007, 81 common seals were recorded to have died as a result of PDV. Single dead seals are reported practically daily from Tanum in the north to Ven in the Øresund (see map). There are no positive cases reported from the northern large seal colonies at Kosteröarna on the Swedish-Norwegian boarder and the outer Oslo Fjord. This implies that the virus is present in all local populations along the Swedish Kattegat and Skagerrak coast without resulting in a massive seals death. According to Härkönen, it seems to confirm the first prognosis of a death rate of about 300 common seals. This was based on the assumption that almost 60% of the seals will be immune after the 2002 epidemic, which is close to what is considered the 66% benchmark at which the virus cannot cause an epidemic, resulting in an almost complete immunity of seal populations. The Museum is still waiting for the result from IAH, England (see status report 6). As this type of work is not routine and demands more advanced research, it is difficult to say when the results will be available. In the coming weeks regular aerial counts will be carried out along the Swedish Kattegat and Skagerrak coast to determine whether the death rate balances the number of registered stranded and incoming dead animals. No unusual increase in mortality has been reported from the Wadden Sea. Sources: Tero Härkönen, The Swedish Museum of Natural History; Forest and Nature Agency, Denmark Compiled by CWSS, 15.08.2007 (Download status report No. 7)   Status Report No. 6: Results autopsy clearly point to phocine distemper (27 July 2007)   According to Tero Härkönen from the Swedish Museum of Natural History, recently diseased seals, or seals with final-stage symptoms of PD are now stranding along the Swedish coast. The Museum's very experienced veterinarian Anders Bergman has carried out a detailed autopsy on the harbour seal shot at the island Ven in the Öresund, and it showed all typical pathological changes indicative of phocine distemper. Although sequencing of the virus is important to look into mutation rates, and to identify the strain etc., earlier experience shows that seals with the symptoms found in the Öresund seal all proved to be positive for PDV in later analyses. One should therefore be careful to speculate about other infective agents causing the seal deaths in the Kattegat. The epidemiology of this outbreak differs from the two earlier ones since a large proportion of the population is immune to PDV after the 2002 epidemic. Virological samples from some 15 seals and a number of harbour porpoises (of which unusually many have stranded) have been shipped to Dr Tom Barrett at IAH in England for sequencing. First results are expected by the end of next week. Sources: Tero Härkönen, The Swedish Museum of Natural History; Forest and Nature Agency, Denmark Compiled by CWSS, 27.07.2007 (Download status report No. 6)   Status Report No. 5:  Seal epidemic spreading into Skagerrak and Baltic (25 July 2007)   Yesterday, Tero Härkönen from the Swedish Museum of Natural History has carried out an autopsy on a seal, found at Lysekil in the southern Skagerrak.  It appeared that the seal had all the macroscopic symptoms of phocine distemper. Meanwhile, Härkönen's assistants have found seals with macroscopic PD symptoms in the Öresund area. The epidemic is apparently spreading north and south into the Skagerrak and the Baltic area. Virological samples have been taken from the seals and will be investigated in the coming weeks. Sources: Tero Härkönen, The Swedish Museum of Natural History; Forest and Nature Agency, Denmark Compiled by CWSS, 25.07.2007 (Download status report No. 5)   Status Report No. 4:  Sick seal in Varberg (S) (24 July 2007)   During the weekend the seal situation was monitored in the Varberg area on the northern Swedish Kattegat coast (see map). One seal was found with clear symptoms of PDV. By the end of last week no new dead animals had been found in Denmark, indicating a possible fading out of the epidemic. However, the finding at Varberg implies, according to Tero Härkönen from the Swedish Natural History Museum, that the epidemic may now have entered the large seal herds in north Halland, and the risk of the pest taking a much more serious course than expected before the weekend has strongly increased. The surveillance in the area of north Halland will be intensified. Also some dead seals will be taken for further obductions. Sources: Tero Härkönen, The Swedish Museum of Natural History; Forest and Nature Agency, Denmark Compiled by CWSS, 24.07.2007 (Download status report No. 4)   Status Report No. 3:  Dead Seals found in the Swedish Kattegat (12 July 2007)   Dead seals have now been found at the Swedish Kattegat coast. Until 11 July 2007, 10 dead seals with PDV symptoms were found in the southern part of the Swedish Kattegat coast south of Halmstad. It concerned a five year old seal (140 cm), a one year old (110 cm) and the rest were from this year. All had obvious macroscopic symptoms. A further suspect dead seal was found at Hallands Väderö. Virological samples have been taken and will be sent to England for further investigations. The seal haul-out sites on the uninhabited islands around Læsø were checked last week, Thursday 5 July 2007, but nothing abnormal was observed. There is no news regarding the type of the PDV virus. The Danish Veterinarian Institute has not yet been able to determine the PDV-type. On 23 June 2007, an unusually high amount of dead seal pups were reported on the island on Anholt which has caused concern of a new outbreak of a seal epidemic. Staff of the Danish Forest and Nature Agency found 33 dead harbour seals on the small island of Hesselø, Kattegat, on Wednesday 4 July 2007. In 2006, the seal population in the Danish Kattegat was estimated to about 5,200 seals. In 2000, the population was estimated to about 6,300. In 2003 and 2004, the numbers were 5,300 and 3,745 respectively. The calculations have been based on 1-2 aerial counts per year and thus provide only a rough estimate. Sources: Tero Härkönen, The Swedish Museum of Natural History; Forest and Nature Agency, Denmark Compiled by CWSS, 12.07.2007 (Download status report No. 3)   Status Report No. 2:  Dead Seals in the Kattegat (6 July 2007)   Staff of the Danish Forest and Nature Agency found 33 dead harbour seals on the small island of Hesselø, Kattegat, on Wednesday 4 July 2007. There is hence a risk that the so-called seal plague has spread from Anholt, where 60 dead harbour seals, which died from the disease, have been found within the last 14 days. "We cannot say with certainty that the seals on Hesselø have also been hit by the seal plague. We have taken samples from the dead seals on Hesselø, and will send them to the Danish Veterinarian Institute, whose experts will investigate as soon as possible whether it is the so-called seal plague", says state forester Niels Erik Worm from the Forest and Nature Agency. Hesselø and the sand banks around have not been investigated earlier in connection with this year’s outbreak of PDV; many of the seals have been dead for several days or weeks. One of the registered seals was an adult, the others were young seals less than 1 meter in size. The finding on Hesselø was not a surprise because the seals from Anholt also use the sand banks around Hesselø. On the island of Anholt, only one dead seal has been found within the last 3 days. There is no news regarding the type of the PDV virus.  On 23 June 2007, an unusually high amount of dead seal pups on the island on Anholt were reported which has caused concern of a new outbreak of a seal epidemic. The seal epidemic in 2002 resulted in about 22,500 dead seals, mainly common seals, which were registered in the Danish-Swedish-Norwegian Kattegat/Skagerrak area, the Limfjord, the Baltic Sea, the Wadden Sea and the North Sea. In the Wadden Sea 10,656 seals died which was about half of the population. Since then, the Wadden Sea seal population has recovered and 15,426 seals were counted in 2006 (see background information) Source: Press release, information Danish Forest and Nature Agency, 5 July 2007 Compiled by CWSS, 6 July 2007 (Download status report No. 2))   Status Report No. 1: Dead Seals in the Kattegat (25.06.07)   The common seal population on the island of Anholt in the Kattegat in Denmark is stricken by a seal plague – information from the Forest and Nature Agency, based on investigations carried out by the Danish veterinary department (DTU). The seal plague, which may spread to other Danish waters and other countries in Northern Europe, may lead to the death of thousands of seals.  “We are not sure yet which type of virus it is, but this will become clear during this week. However, we can conclude that it is the so called seal plague. Therefore, we fear that we  will see a large number of dead seals on the Danish beaches in the coming months”, says Henrik Lykke Sørensen, national coordinator from the Danish Forest and Nature Agency.     The Danish Forest and Nature Agency, among other things through the work in the protected areas, has the task to support and promote the living conditions of seals in the Danish waters. They have  found an unusually high amount of dead seal pups on the island of Anholt over the week (present 48). This immediately lead to the suspicion of an outbreak of a seal plague, which now has been confirmed. “There is a seal reserve on the eastern part of the island. It is not unusual that we find dead pups – normally we find approximately 30 dead seals yearly. But since Tuesday we have found no less than 48 dead pups” says the keeper from the Forest and Nature Agency, Morten Abildstrøm, on Anholt.   The Forest and Nature Agency has intensified the surveillance and will, if necessary, put down seals which lay weakened on the beach of the island. The Agency will at that same time cooperate with the local authorities in order to remove the dead seals. “We will follow the case closely and have called in our national cooperation partners to a meeting regarding the matter on Thursday June 28th. At the same time, we have informed our neighboring countries about the outbreak” says Henrik Lykke Sørensen.  Information provided by: Ribe Environmental Center.     Background Information Marine Mammals   Common Seals in the Wadden Sea in 2006   Reijnders et al., 2005. Marine Mammals. Quality Status Report 2004     Reports from the Seal Distemper Epidemic in 2002   Status Report No. 45 (07.04.2003) Seal Distemper Epidemic amongst Seals in 2002 (Wadden Sea Newsletter, November 2002) Texel Symposium, November 2002 "Management of North Sea Harbour and Grey Seal Populations" (WSE No. 17) Dietz et al., 2003. Sældøden i Danmark 2002. Status over indsamling, omfang og prøvetagning af spættet sæl (Phoca vitulina). Arbejdsrapport fra DMU, nr. 177 NEW: Seibel. H., Baumgärtner, W., Müller, G., Wohlsein, P. & Siebert, U., 2007. Retrospektive Analyse der zwei Seehundstaupe-Epidemien in der Nord- und Ostseee 1988 und 2002. Härkönen, T., Dietz, R., Reijnders, P., Teilmann, j., Harding, K.,Hall, A., Brasseur, S., Siebert, U. Goodman, S.J., Jepson, P.D., Rasmussen T.D., Thompson, P., 2006: A review of the 1988 and 2002 phocine distemper virus epidemics in European harbour seals. Reinkeing, Bettina, 2004. Das Seehundsterben 2002 – Ausmaß, Ursachen und Folgen (Phocine Distemper Epidemic amongst Seals in 2002 - Extent, Causes and Consequences). BSH Symposium, Hamburg.   Further Links The Netherlands: Dutch Ministry for Agriculture, Nature Management and Fisheries Germany Wadden Sea National Parks Schleswig-Holstein / Hamburg / Niedersachsen Denmark Danish Forest and Nature Agency Sweden Swedish Museum of Natural History UK Ireland Seal Mammal Research Unit (Scotland, UK) The Irish Seal Sanctuary (Ireland)       Top of Page