Cod is one of the Baltic Sea’s largest predatory fish and plays a key role in the ecosystem. Over several decades, cod stocks have declined dramatically as a result of overfishing, mismanagement, and unfavorable environmental conditions. Today, the stock consists mainly of small, slow-growing fish, and only one area in the Baltic Sea still has the oxygen and salt levels required for cod reproduction – around Bornholm. Several measures are needed for the stock to recover, from reduced eutrophication to better fisheries management. But is there anything that can be done here and now to strengthen the stocks?
ReCod – a chance for cod
The aim of the ReCod project is to see if it is possible to increase the number of small cod in the sea with restocking, as a step towards strengthening the eastern Baltic stocks. ReCod is also examining the optimal fish size that is best able to survive and establish itself, and what it costs. If the trials are successful, there is a possibility of re-establishing cod in several locations in the Baltic Sea, which would increase the chances of preserving and protecting the unique eastern Baltic cod.
The first years, 2020-2024
ReCod – release of small cod in the Baltic Sea was carried out by BalticWaters and Uppsala University at the Ar research station on Gotland – in the middle of the Baltic Sea. The first five years at the Ar research station contributed new knowledge about how cod can be caught, how they should be kept and thrive in tanks, what is required for the fish to spawn naturally, and how eggs are collected and hatch into small cod larvae. The 4–6-day-old cod larvae were then released at selected locations in the Baltic Sea. Within the project, approximately 1–1.5 million cod larvae have been released annually. Test fishing and scientifically based sampling have been carried out on an ongoing basis to follow up the project. However, the mortality rate of cod larvae in the sea is high, so the next natural step is to feed the larvae to small fry to increase their chances in the wild.
Next step
When BalticWaters Fish Laboratory is completed at the end of 2025, new cod will move in and take the project to the next stage. Hatched cod larvae will be fed to small fry, initially to around 2 cm, for release into the Baltic Sea. Research and method development will be carried out throughout the project period.
The first five years of ReCod – the release of small cod into the Baltic Sea – were funded and carried out by BalticWaters and Uppsala University. In addition, there are a number of partners who contribute to the project in various ways: Bank of Åland through their programme Baltic Sea Project, Ørsted, Leader Gute, Region Gotland, Swedish University of Agricultural Sciences and the Ulla and Curt Nicolin Foundation.
From 2025 onwards, ReCod will be funded and implemented by BalticWaters, with support from the Swedish University of Agricultural Sciences and Sörmlands Sparbank.
