Bladderwrack - Fucus vesiculosus 



Species Number of  genetic studies Baltic population structure Baltic population diversity Baltic effective population size Temporal data Genetic risks Management recommendations
Fucus vesiculosus
5-10 Fine-scaled, discrete Low compared to North Sea Unknown (<100 in related species) None Loss of genetic variation in marginal areas of the Baltic Monitoring genetic variation and levels of connectivity in marginal populations (northern/eastern Baltic). Identification and protection of "source" populations.










Mapping Baltic Sea genetic biodiversity

These maps show mean differentiation of populations, and location of major genetic discontinuities in for bladderwrack (Fucus vesiculosus)


Fig 1. Barriers of gene flow

Three major barriers to genetic exchange was observed for bladderwrack (Fucus vesiculosus).

Full lines are barriers supported by at least half of the scored gene loci. Dotted lines are barriers supported by less than half of the scored loci.


Fig 2. Genetic divergence

The degree of genetic divergence among populations was classified.

Red dots: populations more genetically divergent than the average divergence among populations.

Blue dots: populations less genetically divergent than the average.

Peripheral populations are generally more diverged (more genetically unique) than central populations.

These are preliminary results (January 2012). Full and additional results on Baltic Sea genetic biodiversity will be presented in a coming scientific report. 

Summary of key published genetic information

Current knowledge of bladderwrack population differentiation comes from a limited number of studies looking at a small number of microsatellite markers (maximum 9). There is no data on genetic variation in allozyme, mtDNA or nuclear markers. Hence, conclusions on genetic diversity and structure remain preliminary.

There appear to be generally low levels of gene flow among populations with signficant genetic differentiation found at a distance of around 1 km or sometimes less. This is probably explained by attached adults and a very short dispersal of eggs and sperm during sexual reproduction. Long-distance dispersal is likely to be occasional through rafting but to establish in a new area may require ripe individuals of both sexes to arrive to the same spot.

As in Fucus radicans, there is a potential for cloning in F. vesiculosus but clones are much less common than in F. radicans, and mainly found in the northern part of the Baltic Sea (Gulf of Bothnia).

Both Fucus radicans (A) and F. vesiculosus (B) form new individuals by asexual recruitement. Clones found in more than one site are coloured while black and white sectors represent clones only found in one local area. Grey areas represent proportions of sexually recruited individuals.  


Key publications

Tatarenkov A, Bergström L,  Jönsson RB, Serrao EA, Kautsky L and Johannesson K 2005. Intriguing asexual life in marginal populations of the brown seaweed Fucus vesiculosus. Molecular Ecology 14:647-651. PubMed


Tatarenkov A, Jönsson RB, Kautsky L & Johannesson K 2007. Hierarchical genetic structure in the marine alga Fucus vesiculosus (Phaeophyceae) over spatial scales from 10 m to 800 kmJournal of Phycology 43:675-685.


Johannesson K, Johansson D, Larsson KH, Huenchunir CJ, Perus J, Forslund AH, Kautsky L, Pereyra RT. 2011. Frequent clonality in fucoids (Fucus radicans and F. vesiculosus; Fucales Phaeophyceae) in the Baltic Sea. Journal of Phycology 47:990-998.


CONTRIBUTORS (January 2012)
Kerstin Johannesson, University of Gothenburg, Sweden
Linda Laikre and Lovisa Wennerström, Stockholm University, Sweden

Responsible editor: Kerstin Johannesson, University of Gothenburg, Sweden 
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