Pesticides, e.g. from agricultural fertilisers, enter the oceans via the rivers. Due to the high nutrient input, some algae grow in greater numbers, causing smaller organisms on the seabed to die and the ecosystem to lose its balance.

Microplastics enter the organs and fatty tissue of seals via the food chain. It comes from carelessly discarded rubbish and from plastic textiles (from washing), skin creams, shower gel, shampoo and cleaning products that end up in the sea via wastewater.

Ship engines, drilling platforms and wind turbines generate underwater noise that affects the behaviour of marine animals. They avoid noisy areas, which affects their foraging behaviour and health. Extremely high noise levels can also damage the hearing of seals and fish.

Seals mistake rubbish for food and fall ill or injure themselves. Old fishing nets, so-called ghost nets, and plastic bags are a major problem.

The many negative environmental influences ensure that seals have a weakened immune system and are more susceptible to disease. In Germany, there have already been two epidemics in which many seals have died on the German coasts.

Take your rubbish with you and collect rubbish on the beach to protect animals.

Opt for unpackaged products, cloth bags and reusable bottles.

Use cosmetics and cleaning products without microplastics – apps help you make the right choice.

Buy organic food and sustainable fish products to reduce pesticides.

Stay on the beach and avoid dunes – they are a habitat for animals and protect against flooding.

Choose environmentally friendly sun creams and let them soak in before swimming.

Look out for ground-nesting birds – they are often well camouflaged.