Postmortem Health and Pollution Investigations on Harbor Seals ( Phoca vitulina ) of the Islands Helgoland and Sylt

Abstract

Helgoland and Sylt are important centers of tourism in the North Sea. Harbor and grey seals are one reason for the attraction of these islands. However, little is known about these local seal groups. The present postmortem health and pollution study describes a multiparameter investigation of five ill harbor seals which were shot for animal welfare reasons. Firstly, results of pathology and blood investigations support the bad prognosis of survival made in the field. Signs of inflammation in organs, malnutrition, a high-stress level, and reduced thyroid activity were found. Secondly, metal and organic contaminants were investigated. Metal pollutants in blood, liver, muscle, and kidney tissue were not elevated. Lead and mercury concentrations showed a decreased level compared to former studies. Additionally, interesting insights were found for several organic contaminants in comparison with other studies. The Helgoland seals may be influenced by the contaminants of the Elbe plume.