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.

Essential and Toxic Elements in Blood Samples of Harbor Seals (Phoca vitulina) from the Islands Helgoland (North Sea) and Anholt (Baltic Sea): A Comparison Study with Urbanized Areas

“…For most elements no differences were detected between Helgoland seals, which were suspected to be healthy, and four diseased animals (Table 5; Kakuschke et al 2012).…”

“…Seals living closed to coastal areas are strongly influenced by anthropogenic activities impacting on their habitat, such as fishery and environmental pollution. For these ecosystems, organic and metal contaminant concentrations have been analyzed in several tissues, e.g., in liver, kidney, or blubber from harbor seals, obtained during postmortem investigations (Boon et al 2002;Das et al 2008;Ahrens et al 2009;Kuenstl et al 2009;Weijs et al 2009a, b, c;Agusa et al 2011;Kakuschke et al 2012;Dietz et al 2012). Blood sampling of harbor seals is considered minimally invasive and allows the analyses of pollutants, biomarkers, and health parameters additionally to in vitro cell experiments from living animals.…”

C‐reactive protein in blood plasma and serum samples of harbor seals (Phoca vitulina)

“…This finding was also confirmed by a postmortem study of harbor seals collected in Helgoland and Sylt (Kakuschke et al . ). These animals showed severe systemic diseases, e.g ., acute catarrhal enteritis and multifocal bronchopneumonia and elevated CRP levels.…”

“…As mentioned above, CRP levels were higher in the animals Helgoland (this study, Kakuschke et al . ). However, the number of animals investigated was very small and the selection for diseased animals in the postmortem study was very likely the cause of increased CRP concentrations and not the regional location.…”

“…), as well as of five diseased seals, sampled on the islands Helgoland and Sylt (Kakuschke et al . ). However until now, CRP results of a large group of seals living in the Wadden Sea region have not been published.…”