Targeting the restoration actions for endangered trout is more effective with research-based knowledge

The genetic variation of trout populations is important for diverse river ecosystems. A substantial amount of unique Finnish trout populations is lost and most of the remaining populations are endangered. Research communication and implementation plays a significant role in the protection of trout populations and the restoration of their habitats. 

We studied the diversity and structure of trout populations in rivers in the Nordic research collaboration. Based on results, the trout populations are small and local, and the fish introductions do not have an impact on natural spawning communities. Results showed that reproducing trout individuals are highly important for the survival of trout population. This highlights the importance of local fisheries management.

Environmental factors have a strong effect on the viability of trout juveniles. For example, the solid matter loading from the catchment area is known to reduce the survival of trout eggs.

 As a new information, we demonstrated that the survival of hatching eggs in a river with a solid matter loading is lower than that of eggs hatched in clean gravel shallows. Further, the young fish will be smaller in size, and their metabolism will be faster than in fish that developed in the clean gravel. 

The Nordic cooperation of researchers, authorities, and companies aims to increase the diversity of river ecosystems and improve the state of endangered trout populations. The most effective way is to support the natural reproduction of trout.

Restoring the lifecycle of trout populations requires more understanding of the behavior, genetics, and climate change adaptation of trout. We do not completely understand why some trout remain in small streams for their entire lives while others out-migrate to wider areas. 

We also need more information on how the changing climate and the changes in land use could be better taken into account in the planning of restoration measures. Research knowledge and monitoring helps us to target the restoration actions better in order to protect trout survival. It will also help us to learn from past mistakes and make cost-effective decisions.

New research information enables new possibilities for increasing citizen knowledge. We tried the Finnish Public Service Media Companys public service announcements as a new communication channel to reach the public in 2023. Our aim was to increase responsible citizen activities towards nature. 

The campaign reached almost 1.5 million Finns through television and 0.4 million through social media during summer 2023. The campaign highlighted the citizen’s possibilities to influence the conservation of trout populations and the restoration of their habitats. 

“We wanted to communicate that everyone can act for the river ecosystems and support biodiversity. With the public service announcements, we were able to reach a much wider audience than using traditional research communication methods” says Programme director Meri Kallasvuo.