Sealpups dying off the coast of Germany

Experts Baffled by Mass Seal Pup Deaths

A rash of deaths among young seals along the North Sea coast has puzzled German marine biologists, who wonder whether the deaths represent a worrying trend for the local ecosystem. In Schleswig-Holstein, most of the seal pups born in 2009 have perished.

German marine biologists have been left scratching their heads by a disturbing trend in the North Sea. Within the past year, more than 900 dead seals have washed up along the North Sea coast in the state of Schleswig-Holstein, according to a report released this week by the state. Researchers fear extreme winter conditions may have weakened the animals and put them at greater risk for illness and parasites.


"A certain number of dead seals are normal, but three times as many seals as usual died in the past fall and winter," Kai Abt, a biologist at Wildlife Consulting in Kiel, who carried out the report for the state told the German news agency DDP. Abt believes that the lion's share of seals born in the area in 2009 have perished.

Researchers are now seeking to determine the exact causes of death. In many cases, researchers believe, the seal pups may have fallen victim to parasites. In post-mortem examinations of seals, researchers in the state said that the pestilent lungworm parasite had been found often in the more than 200 bodies they inspected. Lungworm is common in mammals including rats, cattle and cats. The parasites usually live in the respiratory and vascular systems of animals and in many cases lead to pneumonia and bacterial infections. Hungry seal pups are more vulnerable to lungworm, which can often lead to death.

Researchers have ruled out the possibility that the deaths were caused by phocine distemper virus, which caused a mass die-out of seals along the North Sea coast between 1988 and 2002.

A Global Warming Connection?

For his part, Abt suspects there may be a link between climate change, the corresponding influx of nutrients from the Atlantic Ocean into the North Sea and the rising number of dead seal pups. Abt believes the phenomenon may be influencing local fish stocks and causing a food shortage -- one that can be fatal to young pups that are still learning how to hunt and survive and cannot dive as deep for food as mature seals. The young seals typically feed on flounder, crab, and other small fish.


But other scientists dispute his thesis, arguing there is no proof that food stocks for young seals have been reduced.

Just last summer the state's seal population reached 8,415, its highest total since records started being kept in 1975. And in the nearby state of Lower-Saxony, the seal population is nearly as bountiful, with the state recording its second-highest seal population in 2009. The state also reported deaths of approximately 100 seal pups last year, but officials said that figure was not significantly greater than in other years and was likely attributable to the extreme winter. In recent years, the total population of seals off of Germany's North Sea coast has risen by between 10 and 20 percent.

Whether a bewildering trend or a seasonal exception, all researchers involved agree that the North Sea ecosystem needs further study in order to explain the causes of why so many seal pups are dying.