The bivalve project

Photos: with Copyright

Sweden: The bivalve project


Over the past years, an increasing number of reports about declining blue mussel (Mytilus edulis) and oyster (Ostrea edulis) beds have been received by Swedish researchers and by the Swedish agency for marine and water management. In accordance, populations of blue mussels and oysters are known to be declining in many parts of Europe. However, as there is no monitoring of these species in Sweden, and as the knowledge of past and present distribution is fragmented, the validity of these observations is hard to confirm. Moreover, little is known about the pressures affecting the bivalve beds in Sweden. In contrast to many parts of Europe, exploitation of wild bivalve beds, especially blue mussel beds, is very low in Sweden, and pathogens affecting bivalves in Europe are less frequent or absent. The effects of other factors may thus be more pronounced on bivalves in Sweden compared to in Europe, e.g. interactions with the Pacific oyster (Magallana/Crassostrea gigas). There is also a lack of knowledge relevant for formation of informed management strategies related to native bivalves, e.g genetic structures and dispersal patterns in the Swedish archipelago, and means to handle a decline of these valuable habitats.

The project:

Title: Knowledge base for unified management of OSPAR-listed bivalve beds (“The bivalve project”)
Project beneficiary: IVL Swedish Environmental Research Institute
Project funding: European Fisheries found
Project term: 2018-2021

Work packages:

  1. Quantification of population change of both blue mussels and native oysters (historical data and field surveys)
  2. Identification of existing pressures on Swedish populations (literature review, niche modelling and field trials)
  3. Knowledge development for informed management strategies (genetic diversity and population structures and connectivity)
  4. Initiation of stock enhancement trials
  5. Collating knowledge on practical prerequisites for stock enhancement (e.g. legal frameworks and spat availability) and develop national and international networks


The overall objective with this project is to determine if native bivalve beds in Sweden are declining, evaluate causes to population changes and test solutions to this challenge. This will contribute to a healthy marine environment with maintained biodiversity, enhanced opportunities for recreational activities and tourism and improvements in local production of sustainably produced sea-food. More specifically, this project will form a knowledge base for formation of future monitoring programmes, establish a knowledge baseline for management efforts such as protected areas and stock enhancement, and will put the Swedish situation into an international context, from which much can be learnt.


Åsa Strand
IVL Swedish Environmental Research Institute Sweden