Old and new threats
Intense hunting
Around year 1900, there were probably some 100,000 grey seals in the Baltic Sea. But by 1940, their numbers had decreased to 20,000 — the result of intensive hunting. The seals were hunted for their fur and blubber, and also because they competed with humans for fish resources.
Environmental poisons
By 1975 there were fewer than 4,000 grey seals remaining in Swedish waters. They were no longer being hunted, but they were taking in large amounts of poison with the fish they ate. The poisons were chemicals used by humans — in industrial processes for example, or to eliminate insects from cropland.
New offspring
Research conducted by the Swedish Museum of Natural History revealed that the poisons were damaging the uteri of many females, making them sterile and unable to produce young.
Recovering population
Today, the worst environmental toxins are banned and poison levels have decreased in both fish and seals. As a result, the grey seal population is increasing again. In recent years their numbers in the Baltic Sea have been estimated at around 66,000.
