The sun frees Airisto of ice and warms up its waters

The sunlight gleams in Airisto, melts what is left of the ice and starts to warm up the literally ice-cold water. In sheltered coastal shallows, the warming is quick, but in other areas warming such a large mass of water takes a long time. However, this does not deter fish from seeking out their spawning sites in anticipation – soon it is time to breed!

After the winter, the water is clearer than in the summer, but the sunlight penetrating the water soon causes algae to start photosynthesising and growing. Dinoflagellates and diatoms are the first to start growing; their ‘blooming’ stains the water brown, sometimes even reddish. Other factors that can increase the turbidity of the waters of Airisto in the spring include soils from fields and in the melt water carried by the River Aura.

The underwater nature of Ruissalo
The coastal waters of Ruissalo have been taken over by round gobies and Harris mud crabs!
Fish spawn in the spring