The sturgeon project in 2025 – where we are now

In 2025, the focus is on scaling up the project, securing further funding and setting the direction for the coming years. Here is a summary of the summer.

Arken and Graalen – home to thousands of Atlantic sturgeon
The first 95 fish are nowhere near enough to establish a population, so we need to house sturgeon over winter for release in spring. The organisations have chosen mobile units that can be relocated when needed. Two shipping containers were fitted out: Arken, built and run by Sportfiskarna in Gothenburg, and Graalen, built and run by Miljöteknik i Väst, with Dan Calderon playing a key role. Arken is an insulated 40-foot container with two large raceways running along its sides, equipped with pumps, filters, pipes and water treatment. Graalen has a similar design. Getting these systems to work has been challenging, so winter 2024–25 was spent building expertise and making improvements. Together, Arken and Graalen successfully raised around 140 fish to a size suitable for Floy tags and acoustic telemetry. They were tagged in May 2025 and released into the river in June. All acoustically tagged fish were released using the soft-release cage at Lilla Edet. During summer, further Floy-tagged sturgeon were released during visits by funders and at public events. A larger batch of young sturgeon arrived in late August, and several thousand were released directly into the river in accordance with the permits. Some will remain in Arken and Graalen over winter, growing in warmer indoor water to form the basis of the 2026 releases.

Marathon swimmers and valuable bycatch reports
The first reliable bycatch reports arrived in spring 2025. These are an important way for the public and commercial fishers to help us understand the Atlantic sturgeon’s movements and life cycle. The fish is fully protected and must be released, but reading the four digits on its yellow Floy tag and, if possible, weighing and measuring it provides valuable information. By August 2025, we had received these reports: three off Vinga, three along the Bohuslän coast, two in Norway, one in Aalborg, Denmark, and four along the southern Halland coast. The longest-distance swimmer was one of the six fish released at the official event in Kungälv on 18 June 2024. It was found in Farsund, Norway, on 15 May, having gained two kilos and grown 15 cm! Another fish left the cage at Lilla Edet and was found in Ängelholm just four weeks later. Most survived the accidental capture and swam on. A picture is gradually emerging, though still fragmentary: Atlantic sturgeon travel far and wide and like to move! Some remain in the river for a long time, while others head straight out to sea.