Trace metal variations in tissues of harbour seals (Phoca vitulina) stranded along Southern North Sea coasts

• Main Authors: Drouguet, Olivier, Jauniaux, Thierry, Holsbeek, Ludo, Reijnders, Peter, Siebert, Ursula, Das, Krishna
• Format: Conference Object
• Language: English
• Published: 2004
• Subjects: marine mammals; pollutants; trace elements; harbour seals; Phoca vitulina; Life sciences; Aquatic sciences & oceanology; Environmental sciences & ecology; Sciences du vivant; Sciences aquatiques & océanologie; Sciences de l’environnement & écologie; harbour seal
• Online Access: https://orbi.uliege.be/handle/2268/72648

During the last decade, recurrent epizootics have affected harbour seal (Phoca vitulina) populations in the North Sea. The trace metal levels of the harbour seal in the Southern North Sea are poorly known. In this study, trace metal concentrations (Zn, Cu, Fe, Cd, Hg and Se) were measured in tissues (liver, kidney and muscle) of 72 harbour seals collected along the coasts of France, Belgium and Netherlands between 1994 and 2004. Hg levels were significantly higher in seals from the Southern North Sea than in seals from Norwegian waters (1) probably due to the amount of anthropogenic inputs in the North Sea. Hepatic Hg was positively correlated to hepatic Se, both increasing with the length of the seals. Such a relationship reflects an age accumulation process coupled to a detoxication mechanism involving antagonism between Hg and Se in the liver. Increasing Zn and Hg hepatic levels were observed with degrading body condition of the harbour seals, which is reflected by decreasing blubber thickness and high hepatic to total body mass ratio. Body condition was particularly poor in seals which died from infectious diseases. These observations tend to indicate a global redistribution of trace metals from muscle and blubber to liver, as a result of protein and lipid catabolism linked to disease and starvation.