Kolaviken snorkel trail

THE SNORKEL TRAIL CONTENT HAS BEEN REMOVED FOR THE WINTER SEASON 2024-25. At Plagen Beach in the centre of Hanko, you can explore the life of the Baltic Sea below the surface. Follow the snorkel trail and discover the shells, fish and plants that live in the sea!

At Plagen Beach in the centre of Hanko, you can explore the life of the Baltic Sea below the surface. Follow the snorkel trail and discover the shells, fish and plants that live in the sea!

The snorkel trail takes you below the surface to six different points where you can learn about a variety of marine plants, algae and animals. Each point has a sign at the bottom with information about the different species.

The snorkel trail is about 500 metres long and the depth varies between 1 and 2.5 metres. Points 1-4 are suitable for children and beginners, while points 5-6 are slightly deeper.

To see below the surface, you will need a diving mask. A snorkel and fins make snorkelling easier. 

Remember that snorkelling is at your own risk, never go snorkelling alone!

Get to know life under the surface

Kolaviken is a near-shore habitat, with fine forest-like bladder wrack vegetation and seagrass meadows.

Bladder wrack is an alga that attaches itself to rocks and cliffs, providing habitat for many small animals.

Sandy seagrass beds are home to small fish such as Straight-nosed pipefish and flounder.

Many species also live burrowed in the soft sandy beds. Learn about the three most common mussel species in the Baltic Sea: the Lagoon cockle, the Softshell clam and the Baltic clam.

Follow the marine research in Kolaviken

The University of Helsinki's Tvärminne Zoological Station also conducts marine research in Kolaviken.

The yellow measuring buoy monitors variations in temperature, salinity, oxygen content, pH and turbidity in seawater. The buoy is part of the buoy network (Monicoast), and during ice-free periods you can follow the data they measure in real time. 

ARMS is a research tool that collects data on marine species. Similar instruments can be found in seas around the world, and are particularly useful for monitoring invasive species such as the Bay barnacle. The ARMS plates are periodically retrieved from the sea and the species found are analysed using genetic methods.

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