Welcome

This international symposium brings together scientists, experts, and other stakeholders to share best practices on restoring freshwater habitats and improving our understanding of the status of migratory fishes.

Contact: restofish@luke.fi

Theme

Major ecosystem changes resulting from climate and land-use alterations often have severe negative impacts on diadromous species. The stock sizes of, for example, Atlantic salmon, European eel, sea trout, and sea lamprey have already declined across their range, resulting in diminished ecosystem contributions and opportunities for fishing. Securing the future of diadromous fish populations depends on enhancing the recruitment and reproduction of these species despite these declines. Habitat restoration plays a crucial role in the solution, improving the availability and quality of freshwater and marine habitats that are critically important for diadromous fish populations.

With the implementation of the EU Habitat Restoration Law, Water Framework Directive and other initiatives across the international range of diadromous species, a significant increase in restoration efforts is anticipated. However, the outcomes of these efforts do not always meet expectations. Furthermore, restoration guidelines are often driven by intuition rather than scientific evidence, with inadequate attention to the key factors causing habitat bottlenecks for fish. There is limited prioritisation and often little or no monitoring before, during, or after restoration activities. This calls for a review of successful restoration practices, in terms of their effects on fish stock status and on contributions to enhancing sustainable use.

This primarily in-person symposium is aimed at all those involved in habitat restoration and those interested in the broader impacts of restoration on diadromous stocks and fishing opportunities. The goal is to synthesize evidence of both restoration successes and failures and based on this to develop science-based guidelines for a better integration of restoration projects into stock assessments and advice on sustainable uses. We also aim to publish a special issue of peer-reviewed scientific papers.

We invite abstracts on all key themes covered by the symposium, which include:

1. Restoration successes, failures, and lessons learned

This session explores real-world experiences in habitat restoration for diadromous fishes, highlighting both successes and failures. Through case studies and comparative analyses, participants will discuss key ecological, technical, and management factors that determine restoration outcomes, identifying lessons learned and best pathways to improve future initiatives.

1. Social aspects of restoration, what are the hurdles to implementation and how do we solve them?

Restoration is not only an ecological challenge but also a social one. This session focuses on the human dimension of restoration, including governance barriers, stakeholder engagement, funding constraints, and public perception. Presentations will address strategies to overcome socio-political and economic hurdles to ensure effective and equitable restoration of diadromous fish habitats.

1. Best practices and latest tools to design and monitor restoration — how do we set the target?

Defining realistic objectives and assessing outcomes are critical steps in restoration planning. This session presents state-of-the-art methodologies and technologies — from remote sensing to ecological modelling and bioindicators — used to design, implement, and monitor restoration projects. Discussions will centre on how to define restoration priorities and establish clear, measurable targets that align with ecological and management goals.

1. Climate-smart habitat restoration for diadromous fishes

As climate change reshapes aquatic ecosystems, restoration efforts must adapt. This session examines climate-smart approaches that enhance the resilience of diadromous fish populations and their habitats. Topics include integrating climate projections into restoration design, improving habitat connectivity, and applying adaptive management to mitigate the impacts of warming, altered hydrology, and extreme events.

Getting here

Oulu Airport is approximately 22 km from the campus. Taxis (approx. €40–55) take about 20 minutes. Bus line 8 offers a direct connection to the university area, with a stop near the symposium venue at Pentti Kaiteran katu 1. The journey takes around 45–50 minutes.

Finnish Railways (VR) operates multiple train services each day. Timetables for trains can be found online.

Getting around

Oulu boasts excellent public transportation and one of the most extensive cycling networks in the world. During summer, local buses, rental bikes, and e-scooters provide convenient and sustainable ways to explore the city. For route planning and ticket information, visit the Oulu Regional Transport website.

Summer weather

In late June and early July, daytime temperatures in Oulu typically range between 16°C and 20°C, while nighttime temperatures can drop to around 12–14°C. Thanks to the northern latitude, daylight lasts nearly around the clock at summertime.

Programme

The programme of the symposium will include scientific oral and poster presentations, and a panel discussion, not forgetting casual discussions over breaks and visits to locally significant restoration sites.

Side Event

On Monday, 29 June, a Workshop on Thermal Infrared Imaging of Rivers will be organised as a side event of the symposium.

Synopsis:

Cold-water refuges are critical for ensuring the persistence and conferring resilience of cold-water fishes in a changing climate. Identifying the locations of cold-water patches that may serve as refuges for these species is an essential first step in prioritizing restoration actions or implementing protections for these critical fish habitats. The use of aerial thermal infrared (TIR) imagery has proven extremely effective in mapping at large (by helicopter) or small (by drone) spatial extents within rivers and tributaries.

The Atlantic Salmon Federation (Valerie Ouellet, VP Research & Environment), in collaboration with the TITAN-RIVERS network, plans to bring TIR experts (Steve Dugdale, University of Nottingham, UK; Baptiste Marteau, Université de Rennes 2, France; and others) to host a one-day workshop. The objective of the workshop is to equip the participants with the knowledge and understanding required to develop a thermal infrared imaging system to conduct surveys of nearby rivers, including camera platform options, appropriate thermal and optical imaging cameras for image acquisition, and workflows and techniques for analysing the acquired data, as well as examples of applications.

Participation will be limited to 40 people, and registration will open alongside the symposium registration.

Excursions

The symposium includes two field visits combining cultural and ecological aspects. Hupisaaret City Park has great cultural-historical significance, and it has been classified as a regionally important landscape in Finland. The park consists of several small islets, with a stream network that is nearly 2 km in length. It represents a locally significant success story in habitat restoration for the endangered sea trout, offering a unique atmosphere for educational, recreational and research purposes. In the Iijoki watershed, we will visit sites of intense habitat restoration efforts, such as River Livojoki. Bus transportation to these sites will be organized from Oulu on the last day of the symposium.

Call for abstracts

Abstract submission will open in early 2026! We invite abstracts for oral and poster presentations on all aspects of restoration science relevant for the symposium theme. Details on the submission process and abstract guidelines will be announced on the symposium website closer to the opening date.

Registration

Registration will open at the beginning of March 2026.

ICES-sponsored travel grants

As part of ICES co-sponsorship of the symposium, a call for travel grants targeted for early career scientists (ECS) will open in early 2026.

Details of the selection criteria and application process will be published prior to the opening of abstract submissions.

Organizers

Scientific Committee

• Chair: Johan Höjesjö, Gothenburg University
• Carlos Alexandre, University of Evora
• Joana Boavida-Portugal, University of Evora
• Anne Cooper, ICES
• Johan Dannewitz, SLU
• Pauliina Louhi, Natural Resources Institute Finland (Luke)
• Hannu Marttila, University of Oulu
• Hugo Maxwell, Marine Institute
• Raisa Nikula, Natural Resources Institute Finland (Luke)
• Jenni Prokkola, Natural Resources Institute Finland (Luke)
• Alan Walker, Centre for Environment, Fisheries and Aquaculture Science (Cefas)
• Karen Wilson, University of Southern Maine

Local organization committee

Natural Resources Institute Finland

Jenni Prokkola, Raisa Nikula, Pauliina Louhi, Riku Rinnevalli, Minna Oksanen

University of Oulu

Hannu Marttila, Stefan Prost

How to become a sponsor?

To become a sponsor of the symposium, please contact restofish@luke.fi. All sponsors and partners will have their logo attached to our website and programme of the symposium and displayed during the meeting. Exhibitions may be set up for the duration of the meeting.