Posts Economy, Environment, Fish

The interests of hydropower companies and ways to enable migratory fish to reproduce in large regulated rivers may seem a definite conflict. But Luke’s senior scientist Aki Mäki-Petäys is convinced, the two can be combined.

“In free-flowing rivers migratory fish, such as Baltic salmon, brown trout and whitefish, migrate upstream to spawn in suitable reproducing areas. But if rivers are dammed to produce electricity, the migration of fish is hindered, and something has to be done,” Dr. Mäki-Petäys explains.

Dr. Mäki-Petäys says, that the migratory fish presumably are able to store in their memory the smell or the scent of the very spot of the river where they have been born. How the fish do this and what causes the drive to return to their birthplace from a long sea journey, which may take 1–4 years, is truly mysterious.

“Juveniles of migratory fish are usually released into the regulated rivers to compensate for the loss of natural reproduction. Returning adult fish can be transported to their upstream reproductive environments or, alternatively, fishways can be constructed to get the fish through or around dams.”

Radio telemetry is a common method for monitoring the movements of migratory fish in regulated rivers. Photo: Panu Orell.

Different rivers, different solutions

The challenge is, however, that what may work in one river may not work in another. To create specific and working strategies for each location, scientists, government experts and the industry have created a model where collaborative research is conducted combining the expertise from different sources.

Senior adviser Jukka Muotka from Fortum explains how the industry can support research to find the best solutions.

“At Fortum, we have expertise in river hydraulics and hydrology as well as very sophisticated modeling methods to the see how different flows affect water levels, flow velocities and turbulence in different parts of river. The effect of these on the behavior of the migratory fish can then be analyzed by fish biologists,” Muotka explains.

“In the absence of collaboration, this sort of knowledge is not directly available for scientific research. We have a keen interest to maintain thriving migratory fish populations in Finland and work together with the scientists enabling them to get a direct access to our data.”

Unique Migratory Fish Forum

In Finland, practically all relevant rivers for power plant industry are also historic home rivers for migratory fish. Compared to some other countries, Finland started to tackle the issue of allowing the fish to migrate back to their natural reproductive areas relatively late.

In Sweden, for instance, Fortum has been successfully transporting migratory fish to their upstream habitats for decades.

“I think the main thrust to tackle this issue came from the European Union initiatives. Then, from late-1990s, we have been building joint research programs and experiments with the power plant companies,” Dr. Mäki-Petäys says.

In 2010, the Migratory Fish Forum was launched. Here, the government, industry and scientists meet regularly and plan research projects and experiments to find the most effective ways solve problems related to migratory fish restoration in regulated rivers.

The goal of the forum is crucial: dams disturb the natural life cycle of the migratory fish and the forum seeks ways to synchronize the interests of the increasingly important energy production while allowing the fish to migrate.

To achieve the best methods for facilitating restoration of migratory fish populations will take time. The unique Finnish roundtable model has proved to be effective.

Patience is of essence

“It is very rare that the industry, government and the scientists can work together with such ease and fluidity like at the Migratory Fish Forum. From my experience I know, that in many countries scientists and the industry do not really get along in the most productive way,” Muotka says.

The work and discussions of the Forum has yielded a common perspective: solutions can be found, everybody has a shared interest and patience is the key.

“There are no quick solutions here. We are learning new tactics every year and from my viewpoint, as a scientist, I see that this is a long process which will take several years, if not decades,” Dr. Mäki-Petäys says.

Cooperation in restoring migratory fish like salmon benefits avid fishermen, too. Photo: Petri Jauhiainen.

The lure of the fish

Aki Mäki-Petäys and Jukka Muotka share a passion for fish and fishing also when off-duty. For the last 40 years, Dr. Mäki-Petäys has been following his passion for fishing salmon, returning to Northern Norway to his favorite fishing spot. Muotka, too, has been an active fisherman and knows the ways of the fish particularly in the waters close to his vacation cabin.

For Jukka Muotka it is sometimes hard to tell apart leisure from work.

“I am passionate about this part of my work where we really create something new. We seek solutions to improve the ecology of the migratory fish in these challenging conditions of rivers with important hydropower schemes. It is as if I´m drawn to these questions intuitively.”

The mystery of the migratory fish, it seems, will easily fuel the collaboration of the industry and the scientists in the future to come.

Text: Miika Vähämaa

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