Merikoski fishway, a well-known landmark in Oulu, provides a path for migrating fish to swim upriver from the sea past the Merikoski hydro power plant. From the migrating fish, especially salmon has attracted interest in public. In 2018, a record of 2 000 salmon migrated through the Merikoski fishway.
Before building the Merikoski fishway, migrating fish could not get past the Merikoski dam for nearly 60 years. The Merikoski fishway has now been standing for 15 years, allowing the gene pools of both the fish from the sea and from the river to mix again.
Especially the salmon has been the subject of interest for a long time. Many are eager to know, how many salmon has migrated through the Merikoski fishway. Anywhere from a hundred to two thousand salmon has been swimming past the Merikoski dam in the past years.
Salmon is not the only fish utilizing the fishway – for example, perch, bream and roach swim through the fishway by hundreds. All the fish are equally as important regardless of their appeal. Last year, a rogue otter was also seen in the fishway, catching itself an easy meal for supper.
A popular sight from the start
Entrance for the fish to the fishway is in the old log floating flume by the Merikoski hydro power plant. The route then ascends to the old riverbed, from where it continues to the final climbing section formed by landscaped, stream-like stretch in the Hupisaari Park.
Even before starting the construction of the Merikoski fishway, it was anticipated that the fishway would generate a lot of interest in the public. Many are keen on seeing the migrating fish up close. Therefore an observation room, also known as an aquarium was built alongside the fishway so that public can watch the fish swimming underwater.
The Merikoski fishway is open from the beginning of May to late October. The aquarium is open to the public during demonstrations arranged a couple of times every summer.
In 2018, a live camera was set in the aquarium. From the live camera’s footage, researchers can determine the species and the length of the fish and estimate its weight. The biggest passing salmon last year was 114 centimeters long.