Narrow wrack - Fucus radicans 



Species Number of genetic studies Baltic population structure Baltic population diversity Baltic effective population size Temporal data Genetic risks Management recommendations
5 Fine-scale, discrete Somewhat lower that in related species   None Loss of widespread clones. Low sexual reproduction in some areas. Highly endangered due to Baltic endemism. Estonian populations (with high sexual activity) in need of particularly strong measures of protection.









Summery of key published genetic information

Current knowledge on the biology and population genetics of narrow wrack is based on a restricted amount of observations and data, as this species was first described in 2005 (Bergström et al. 2005, for reference see below). Moreover, the distribution of the species in the Baltic Sea is yet not clear. It is established in the Gulf of Bothnia north of Öregrund on the Swedish side and from Wasa and northwards on the Finnish side, but its present in the Åland archipelago, along the SW coast of Finland and inside the Gulf of Finland is unclear. However, it appears again on the northern and eastern costs of the island of Saaremaa, Estonia. (These are confirmed appearances of the species, further establishments seems highly likely in these area.)


As for Fucus vesiculosus, local populations may be genetically rather different, even at distances down to a few kilometres. In particular, the number and frequency of clones may vary substantially, also between populations in the same area. One clone (blue in the figure below) is particularly common along much of the Swedish coast as well as in the northern most part of the Finnish coast. Hitherto, no particular characteristics have been found in this clone that explain its wide distribution. Nevertheless, it shows the dilemma of high clonality – if this clone is not able to withstand a slight temperature increase or salinity drop in coming years, a large portion of the species will be eradicated.


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

Bergström L, Tatarenkov A, Johannesson K, Jönsson RB & Kautsky L. (2005) Genetic and morphological identification of Fucus radicans sp nov. (Fucales, Phaeophycaea) in the brackish Baltic Sea. Journal of Phycology 41:1025-1038.


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


Pereyra R, Bergström L, Kautsky L, Johannesson K. 2009. Rapid speciation in a newly opened post-glacial marine environment, the Baltic Sea. BMC Evolutionary Biology. 9:70


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. PubMed


Gylle AM, Rantamaki S, Ekelund N G A et al. 2011. Fluorescence emission spectra of marine and brackish-water ecotypes of Fucus vesiculosus and F. radicans (Phaeophyceae) reveal differences in light-harvesting apparatus. Journal of Phycology 47:98-105. PubMed


Lago-Leston A, Mota C, Kautsky L, et al. 2010 Functional divergence in heat shock response following rapid speciation of Fucus spp. in the Baltic Sea. Marine Biology 157:683-688.


Råberg S, Kautsky L. 2007 A comparative biodiversity study of the associated fauna of perennial fucoids and filamentous algae. Estuarine coastal and shelf science 73:249-258.


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

Responsible editor: Kerstin Johannesson, University of Gothenburg
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