Balticsea 2020

Restoration of bladderwrack - a manual

Bladderwrack is often described as the forest of the Baltic Sea and it has previously flourished in several locations along the Swedish coast. Eutrophication, emissions of pollutants or other sources of human interference have led to the depletion of bladderwrack or its total disappearance. With funding from BalticSea2020, three researchers from Stockholm University's Baltic Sea Centre will be developing a manual that shows where and how bladderwrack can come back.

Background
Bladderwrack is a cornerstone of the Baltic Sea’s species-deficient ecosystem and functions as both habitat and shelter for many species of fish and as food for invertebrates. Within the framework of the BalticSea2020 “Living Coast” project, in 2013 and 2014 the Swedish Water Ecologists began the project “Restoration of vegetation clad bottoms”. The project aimed at investigating the conditions for successful implantation of a number of important and common plant species in coastal bays. One of the species under consideration was bladderwrack, and the results showed that implanted adult bladderwrack, given the right conditions, could survive and expand in the bays. As an extension to this project, researchers from Stockholm University will be producing a manual whose aim is to accelerate the pace of re-colonisation of the bladderwrack along the Swedish coast.

Objectives
The project named “Restoration of bladderwrack – a manual” aims to develop a manual as to how bladderwrack stocks can be restored in areas where seaweed has disappeared or diminished. The manual will contain a list of the factors or parameters requiring measurement and analysis, together with proposals of methodologies adapted for the northern Baltic Sea Proper.

Method
The project will be undertaken in three phases, wherein the first of which will focus on producing a compilation of literature to establish what scientific information already exists with respect to bladderwrack. The manual will then be developed on the basis of this compilation, but will also contain cross-references to scientific sources and reports.

During the second phase, the manual will be tested in the field by means of a number of case studies being carried out in the northern Baltic Sea Proper. First, a number of appropriate locations within Stockholm County will be chosen. The choice will be based on data from national and regional environmental monitoring and inventories and ongoing monitoring programmes being carried out in certain areas. The results of these will then determine which location is deemed the most suitable for successful restoration of the bladderwrack. The project will then undertake the restoration scheme at the chosen location, in accordance with the manual.

During phase three, the manual will be finalised based on the outcomes from phases one and two. It will serve primarily as a practical guide for how to restore bladderwrack and where it is appropriate to implement the measures. The manual is targeted at, for example, municipalities, county councils and the Water Management Association.

The project is funded by BalticSea2020 and will be completed at the end of 2019, for presentation in 2020.

The project is led by:
Lena Kautsky, Professor Emeritus and Senior Advisor, Department of Ecology, Environment and Plant Sciences and Stockholm University Baltic Sea Centre.
Susanne Qvarfordt, PhD. Researcher, Department of Ecology, Environment and Plant Sciences, Stockholm University/marine biologist and environmental consultant at the Swedish Water Ecologists AB,
Ellen Schagerström, PhD. Researcher, Department of Ecology, Environment and Plant Sciences, Stockholm University and Stockholm University Baltic Sea Centre.