Seals 2001 Common Seals in the Wadden Sea in 2001 Common Wadden Sea Secretariat, Wilhelmshaven September 2001 The trilaterally coordinated long time-series of counts of common seals in the entire Wadden Sea were continued in 2001. The time-wise tuned aerial surveys in the different parts of the Wadden Sea revealed the following results. In Denmark, the maximum number of seals counted was 2,380; in Schleswig-Holstein, 7,190; in Lower Saxony, about 6,220; and nearly 3,600 in The Netherlands, amounting to a maximum total number of around 19,390 common seals. The total maximum number of pups counted was 3,957. For ecological reasons, the seals in the German area north of the Hindenburgdamm, the Sylt Rømø Bight, are incorporated in the Danish count. In this area, 344 seals were counted which implies that the actual number counted in the total Schleswig-Holstein area would be 7,534. The this year obtained percentage pups per total number of 20.4% is similar to the average found in earlier years. The increase in total numbers of 14.0% was slightly higher than last year. The latter is primarily caused by a relatively higher increase in both Schleswig-Holstein and Lower Saxony. The overall conclusion from this year's result is that the hitherto observed strong increase in the Wadden Sea seal population since 1989, the year after the virus-epidemic, has continued. The observed annual increase in the years 1997-2000 was persistently below the calculated average increase in the preceding period. That could point to the onset of a reduced growth or just a random temporary event as was also noticed between 1992 and 1995. In contrast, the 2001 results may rather reflect an upward tendency. A reduced growth as a result of the population reaching the carrying capacity of its habitat cannot be completely excluded but seems unlikely. One would then expect alternating years with respectively high and low reproduction, creating a regular biannual pattern. So far, the time-series obtained do not point in that direction. It is emphasized that single year-to-year survey results should not be over-interpreted. The number of seals hauled out will vary slightly due to fluctuations in environmental conditions such as weather and disturbance and do therefore not necessarily reflect population developments. Trilateral Seal Expert Group: NL:  Peter J.H. Reijnders, Sophie Brasseur, Alterra - Marine & Coastal Zone Research, Texel LS:  Ekkehard Vareschi, Universität Oldenburg SH:  Ursula Siebert, Kai Abt, FTZ Büsum der Universität Kiel DK:  Svend Tougaard, Fiskeri-og Søfartmuseet, Esbjerg Figure 1: Number of Counted Seals in the Wadden Sea since 1975   Home | Trilateral Cooperation | News/Service | Management | Monitoring | Interregional Cooperation