First health and pollution study on harbor seals (Phoca vitulina) living in the German Elbe estuary

Abstract

The Elbe is one of the major rivers releasing pollutants into the coastal areas of the German North Sea. Its estuary represents the habitat of a small population of harbor seals (Phoca vitulina). Only little is known about the health status and contamination levels of these seals. Therefore, a first-ever seal catch was organized next to the islands of Neuwerk and Scharhörn in the region of the Hamburg Wadden Sea National Park. The investigations included a broad set of health parameters and the analysis of metals and organic pollutants in blood samples. Compared to animals of other Wadden Sea areas, the seals showed higher γ-globulin levels, suggesting higher concentrations of pathogens in this near-urban area, elevated concentrations for several metals in particular for V, Sn, Pb, and Sr, and comparable ranges for chlorinated organic contaminants, except for elevated levels of hexachlorobenzene, which indicates characteristic inputs from the Elbe.

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

“…Most of the elements showed no significant differences compared to our previous study on seals of the Wadden Sea [3]. Compared to animals of the Elbe estuary, many essential as well as toxic elements showed lower concentrations, possibly due to differences in location and feeding habitats as well as malnutrition and possible liver lesions [12].…”

“…Table S1) [28,29]. Compared to free-living harbor seals of the Elbe estuary, the albumin-toglobulin ratios of all five animals were lower [12], indicating higher amount of globulins in relation to albumin in the sick animals than in clinically healthy seals. The concentrations of the acute phase protein CRP were high or in the upper range compared to reference date described for harbor seals [30].…”

“…Aliquots of plasma were subjected to solid-phase extraction (SPE) and analyzed by gas chromatography-mass spectrometry (GC-MS) following the procedure described in our previous study [12]. The measurements were performed at the University of Las Palmas de Gran Canaria, Spain.…”

“…Number of investigated seals given in parentheses. Data for seals from the Elbe estuary taken from Kakuschke et al [12], for seals from the North Sea from Weijs et al [38].…”

“…However, to describe complex parameters such as the individual health status of marine mammals, an informative set of investigations has to be performed. Recently, we described a study including metals, organic contaminants, selected marker proteins as well as a number of immunological and clinical chemistry parameters to assess the health status of individual marine mammals based on blood samples [12].…”