It’s a damp, grey Tuesday afternoon. A team of volunteers, including four members of the EKOenergy secretariat, march down a farm track in Vaskio, Finland, laden with buckets, shovels and biscuits. We arrive at a small brook, no more than a meter wide, where the water trickles quietly through woods that line fields of buckwheat.
It’s the kind of stream that you would not look twice at during an afternoon dog walk. Yet here is the last known spawning ground for Brown trout in the Halikonjoki river basin in the region surrounding the city of Salo. The autumn spawning season is soon to begin, so our team of volunteers have come to restore some of the spawning grounds damaged by local farming in the region.
Trout do not spawn anywhere in a river, they look for gravel beds beneath running water. Running water ensures that there is a constant supply of oxygen for the eggs to grow throughout the winter months, ready to hatch in early spring. To avoid the eggs from being washed down river, the fish find gravel beds where the eggs can rest in the gaps between the rocks.
These gravel beds are vulnerable, however, to silt blockage caused by soil run-off from local farms and the creation of dams along the river. Dams without fish ladders prevent fish from moving further upstream, disrupting their migration patterns. They also change the flow of the river and cause large amounts of silt to build up. This can be especially destructive if the dam is damaged or destroyed because the silt washes downriver, en mass, blocking up gravel beds downstream.
Silt build-up is likely to be a main driving force for the drop in fish populations across the agricultural region around Salo. Whereas twenty years ago, there were several brooks known to be populated by Brown trout, now there is only one.
Restoring Brown trout numbers is crucial for maintaining biodiversity in the region. These small trout do not spend their entire lives in small streams, they only come here to breed. They spend the rest of the year further downstream where there is more available food and where they act as a food source for larger fish like salmon as well as birds and otters.
EKOenergy’s Environmental Fund supports river restoration work internationally. We ask consumers who source their electricity from hydropower programs to contribute 0.10 € per megawatt-hour to the Environmental Fund in order to allow this important work to take place.
Unfortunately, there are still too many hydropower plants which operate with little care for sustainability issues, such as maintaining minimum water levels in rivers. The Environmental Fund, and those that choose to fund it, make crucial river reconstruction work possible.
Written by Cameron Boggon
Posted on 19 October 2018