Fish are spawning on the underwater reef that fishery biologist John Kärki is making out of recycled Christmas trees.
Old Christmas trees are getting new life on the bottom of lake Mälaren, where they are turned into underwater reefs so that fish can spawn.
A harbour dug out to allow for big boats and cruise ships is not good for fish. That’s why the city of Stockholm and the Swedish Anglers Association have initiated a project to help fish in the lake – and take care of people’s old Christmas trees at the same time.
“Waters that are shallow and have a lot of vegetation are important for the spawning for fish like perch, pike and zander. If we build away these areas, we don’t get enough fish in the sea,” says fishery biologist John Kärki with the Swedish Anglers association.
Kärki and his colleagues have been collecting used Christmas trees from Stockholmers, and use them to create underwater reefs for the fish to spawn in. This winter, over 400 used Christmas trees will be sunk into lake Mälaren.