The most important threats to the common seal in the Wadden Sea are caused by human activities. In the past, seal hunting was the largest threat to these animals. Around 1900, thousands of seals were shot or clubbed to death in the Wadden Sea. Since 1962 the hunt on common seals has been banned in the Netherlands. In 1972 the German state of Lower Saxony followed. Several years later Schleswig-Holstein and Denmark followed the ban as well. Thanks to the ban on hunting the population increased in the years following it. However, pollution and disturbances brought the population down to dangerously low numbers.
Today, the largest threat for the seal population is still pollution. Firstly, in the form of non-degradable substances which stay present in the environment over a very long period of time. There are new pollutants too, of which the effects are not even clear yet. Therefore, more research is necessary, in addition to the research already carried out by the SRRC in 1993.
Secondly, the amount of waste drifting in the sea is increasing. More and more seals are getting themselves caught up in old fishing nets and other non-degradable waste. Another concern is the increase in seal-deaths due to the swallowing of fishhooks.
The increasing use of the Wadden Sea for recreational purposes is causing huge disruption during the birth and nursing periods. In the summer months the Wadden Sea is crowded with thousands of sailing boats and motorised yachts. Tourists often moor their boat on sandbanks, which are also used by seals. Other uses of the Wadden Sea area also cause great disruption.
Disruptions especially pose threats to the pups: Not only are they in danger of losing their mother, but if the young animals are unable to drink enough fatty mother milk during the nursing period due to disturbances, they will be unable to build up the fat reserves that are necessary to help them through the first difficult periods. Without these reserves, they become weak. Without help they will die of hunger.