Restoration and sustainable management of bladderwrack (Fucus vesiculosus) in the Gulf of Riga

Bladderwrack Fucus vesiculosus is one of the most important habitat-forming species in shallow-water hard-bottom algal communities in the brackish Baltic Sea. Fucus vesiculosus communities provide habitat and shelter for numerous organisms and thereby are known as important hotspots of biodiversity. Changes in the structure of the F. vesiculosus community will also affect the ecology of the associated organisms. Fucus vesiculosus is sensitive to environmental changes and a strong decline in depth distribution has been reported during the last five decades for the Baltic Sea. These drastic changes in distribution and biomass have been attributed mainly to the effects of increasing eutrophication and sedimentation. In addition to ongoing activities to decrease the land-based overload of nutrients and pollution, direct in situ restoration actions could reverse these drastic changes in the distribution of F. vesiculosus. The Gulf of Riga is the wide, shallow water basin situated between Estonia and Latvia. Estonia and Latvia are jointly responsible for the environmentally sustainable management of the wild natural resources of the Gulf of Riga and its ecosystem. This project aims to jointly develop and carry out pilot actions for F. vesiculosus restoration in the Gulf of Riga to maintain the health and longevity of F. vesiculosus communities. By conducting field experiments in different bays with different environmental conditions in the Gulf of Riga, we are testing different techniques and approaches for F. vesiculosus restoration. The harvesting of wild macroalgal species is an increasing trend in the Baltic Sea region as the macroalgae can be used in e.g., the food industry, pharmacy, or bioenergy sector. The general increase in stakeholders’ interest in F. vesiculosus harvesting has raised the need for updating legislation to guarantee the sustainability and viability of the Fucus communities. Thus, one of the objectives of the project is to develop guidelines for sustainable management of wild F. vesiculosus resources in the Gulf of Riga. The recommendations will be based on the activities carried out in the project: 1) assessing the current state of F. vesiculosus communities in the Gulf of Riga and analyzing possible factors leading to a decrease of Fucus, 2) testing and evaluating the restoration processes, and 3) assessing the potential for wild F. vesiculosus harvesting to maintain the health and longevity of Fucus communities.