Fascinating nature

Today, Boysen accompanies tourists through his old childhood stomping grounds.

Flounder has always been a staple for the people who live on the western coast of Schleswig-Holstein. The flat fish has an interesting habit - it doesn't always swim out into the North Sea with the twice-daily ebb tide.

Instead it burrows into shallow sand near the tidal trenches of the coastal Wadden Sea, whose seemingly endless tidal mud flats stretch the length of the western coast of Schleswig-Holstein. There, the flounder dozes in the sun, waiting for the tide to rise and carry it back out to the water.

Walking on water

The half-buried flounder aren't visible to the naked eye, Boysen explains. But if you walk out on the mud flats, or Watt, you can feel the fish with your feet and grab them with your hands. It is a practice known as "kicking flounder."

"You only have half an hour before and after low tide to be able to kick the flounder," the 65-year-old Boysen says. "It's the only time you can grab it with your hands." In his youth, Boysen earned his pocket money with this unusual fishing method.

As bored kids, he and his friends would sometimes make the three-hour walk across the tidal flats to the island of Foehr, or to the tiny island of Oland - one of 10 North Fresian islands known as Halligen. Unlike regular islands, the Halligen aren't surrounded by dikes, so they can flood when the tide is very high.

Today, Boysen is a certified tour leader for the Waddensee National Park. He takes hundreds of visitors on tours through the 4,500 square kilometer Wadden Sea coast. The flounder have mostly disappeared from the tidal flats, but now and again on a walking tour, the experienced guide will feel one under his feet, and astonish tourists with an unusual fishing demonstration.

The Wadden Sea tidal flats were declared a nature reserve and national park in 1985. Since then, there has been a rise in tours of the mud flats. "I used to spend maybe 14 days a year in the flats. Today I spend more than 1,000 hours in the national park," explains Boysen. Walking the flats has become a year-round attraction. There are even tours during the Christmas holidays, where visitors walk across the flats to the Halligen for a traditional cabbage supper.

Being a tour guide doesn't pay well enough to feed a family. So like most of the other 250 Wadden Sea guides, Boy Boysen has another occupation and leads tours on the side. "We mostly walk on the weekends and in the summer," says Boysen, whose name is typically Frisian.

A lot of guides give up their vacation to take tours through the flats. "We all love nature, the quiet of the flats, and the good, iodine-rich air out there," says Boysen, who studied agriculture and earns his living as an agricultural consultant.

At up to 30 kilometers wide in some places, the Wadden Sea is one of the most animal-rich ecosystems in the world. Some 60 species of bird come here to feed. At the height of the migratory bird seasons, in spring and fall, some 1.5 million birds can be in the national park at one time.

Shellfish as a water filter

On his tours, Boysen tells visitors about the uses and importance of even the smallest creatures in the tidal flats. Clams and mussels, for instance, act as water filters. A mussel can filter up to 2.5 liters of water per hour, Boysen explains. "Together, the shellfish in the North Sea manage to completely recycle the entire North Sea every two weeks. Without the many life forms, the whole Wadden Sea would be a stinking sewer."