Blue mussels on a rock
Between 2017 and 2018, calculations was made that showed that 10 percent of blue mussels were on artificial surfaces, 40 percent in natural habitats, and 50 percent in farms.
Photo: Inductiveload/Wikimedia Commons

Research project aims to solve the mussel mystery


In recent years it has become more difficult to find blue mussels on the west coast of Sweden. A new project will now dig deeper into the subject.
"We are interested to see how the mussels fare in different environments," says Mats Lindegart, professor at the Department of Marine Sciences."

It has become more difficult for crabfishing children to find blue mussels as bait. However, it is still unclear whether the blue mussel have decreased generally.

"We have poor data on the historical distribution of mussels," says Mats Lindegart. 

However, recent research establishes that blue mussels have declined in natural environments such as seabeds, while thriving in farms and on artificial environments such as piers. Whether the species has decreased depends on when in time the comparison is made. However, according to personal anecdotes it used to be better.

"The general picture seems to be that mussels have decreased, and I do believe so as well. However, we don't know if people remember the mussels when they were most abundant; were there more mussels in general, or were there a lot of mussels only in certain areas?"

Measurement of blue mussel habitats

Porträttbild på man i marinblå tröja framför havet
Mats Lindegart, professor of marine ecology.
Photo: Susanne Liljenström

The lack of data is something Mats Lindegart hopes the new project "Blue mussels – interactions between stocks in natural and artificial environments" (In Swedish: Blåmusslor – interaktioner mellan bestånd i naturliga och artificiella miljöer ) will solve.

"We are interested to see how the mussels fare in different environments. Are there equal numbers of mussels recruited in the different environments, and do survival rates differ?"

The scientists will study areas such as natural soft bottoms, hard bottom environments, artificial structures, and mussel cultivations. Initially, the most vulnerable life stage of the blue mussel is study.

"Then one can get a better grip on whether it is the juvenile mussels that are suffering, or whether it is the older mussels that have a high mortality rate."

Mats Lindegart believes that it has to do with the earlier stages.

"Either there are no larvae, or the larvae die, are eaten, or die for other reasons."

Investigations and experiments 

The project will also estimate population sizes. To do this, Mats Lindegart needs help from the public, as people often refer to the amount of mussels they saw when they were young.

"I would like to gather information from the public, where they can say when and where they saw blue mussels, so that I can get a better overall picture of the distribution of mussels."

At the moment, planning activities for the summer's experiments on mussel larvae, such as plankton samples, is taking place. Together with further studies, they will form the basis for a future comprehensive picture of Swedish coastal mussel populations.

"We have been involved in the gathering of data on the presence of larvae with help from mussels farmers, The Swedish Meteorological and Hydrological Institute, and the Food Safety Authority," says Mats Lindegart. 

Text: Kajsa Centre

Facts about the mussel project

The project Blue mussels – interactions between stocks in natural and artificial environments has received funding of three million (SEK) from the research council Formas and will run until 2025.