Researchers warn there are so many grey seals in Danish waters now that they are threatening the nation’s fishing industry.
Aside from devouring large numbers of fish, the rapidly increasing seal population has also infected the cod population with parasites that make them emaciated and unappetising. The problem is particularly concerning in the Baltic Sea.
“We’ve been able to register that the Baltic Sea cod has gone from having none or very few of these parasites in their livers to having up to 400 in one fish,” Kurt Buchmann, a professor in aquatic pathobiology at the University of Copenhagen (KU), told Baglandet, a radio program on P1.
“It’s quite some change in recent years. We’ve seen the rise in connection with a significant increase in the seal population in the Baltic Sea.”
Uncooked = unwelcome guests
There are two types of parasites in the cod, which both stem from the seal: the liver worm and the cod worm.
The liver worm isn’t dangerous to humans, unless you eat raw cod liver. The cod worm is found in the fillet itself and dies when exposed to high temperatures. But if not, it can burrow into the gut and lead to a serious stomach infection.
The development has reportedly had dire consequences for the Danish fishing fleet operating in the Baltic Sea, particularly out of Bornholm.