Status of the harbour seal (&lt;i&gt;Phoca vitulina&lt;/i&gt;) in Southern Scandinavia

Morten Tange Olsen,Signe May Andersen,Rune Dietz,Jonas Teilmann,Tero Härkönen,Anton Linnet,Susi Manuela Clermont Edrén

doi:10.7557/3.2674

Abstract

The harbour seal population in Southern Scandinavia has experienced repeated declines caused by hunting and epizootics. These events have shaped the current distribution and abundance of the population. This paper assesses the current status of the population. We estimate trends in abundance of harbour seals from long term survey data, compare these with historic trends inferred from previously published material, and discuss past and potential threats to the harbour seal population of Southern Scandinavia. It is evident that harbour seals have disappeared from haulout areas along the Danish shores of Kattegat and in the westernmost part of the Baltic Sea, where they were previously numerous. In the 1920-30s, when abundance was at its lowest, the population is estimated to have been only a fraction of its original size. Following 30 years of protection the population is currently approaching historic abundance and might have reached the carrying capacity in some areas. Further development depends largely on effects of future epizootics, anthropogenic disturbance, and availability of suitable haulout sites.

Highlights

The harbour seals (Phoca vitulina) in SouthernScandinavia have experienced a turbulent history
After protection measures were taken in the 1960-70s the population started to recover, but was struck by two severe epizootics in 1988 and 2002 caused by the Phocine Distemper Virus (PDV), killing approximately half the population on each occasion
This paper summarizes published and unpublished data to assess the current status of the Southern Scandinavian population

Summary

INTRODUCTION

After protection measures were taken in the 1960-70s the population started to recover, but was struck by two severe epizootics in 1988 and 2002 caused by the Phocine Distemper Virus (PDV), killing approximately half the population on each occasion (Dietz et al 1989a; b, Härkönen et al.2006). These events have had significant impacts on the distribution and abundance of harbour seals in Southern Scandinavia. This paper summarizes published and unpublished data to assess the current status of the Southern Scandinavian population. Scandinavian waters and provide a perspective for the future development of the population

MATERIALS AND METHODS

Central Limfjord

Statistical methods

Findings

CONCLUSION