Fucus vesiculosus and F. radicans (wrack species)
The bladderwrack, Fucus vesiculosus L., and the recently discovered, Fucus radicans Bergström and Kautsky, are important perennial macroalgae of the sub-tidal rocky habitats in the Baltic Sea. They provide food and shelter for several invertebrate species e.g. Idotea, gammarids, mysids Palemon, mussels and snails. Within these rich communities fish larvae and may in their turn find food and shelter from larger fish and mature fish may use fucoids as substrate to put their roe on.

In BaltGene we describe the genetic structure of these two Fucus species, focusing on F. radicans that is endemic to the Baltic Sea and originated less than 2500 years ago from F. vesiculosus. We have identified several areas where the two species co-occur e.g. along the Swedish and Finnish coast of the Bothnian Sea and along the coast of Saarema in Estonia. The growth rate and reproduction of these populations will be studied as well as the stress response to environmental factors such as salinity and temperature. Further, we will test the importance of genetic diversity within a species, i.e. compare unique individuals with a large genetic variation to clones for the abundance of a set of common invertebrate species. The aim is to test the importance of genetic variation for biodiversity and function at the habitat and ecosystem level. The studies also aim at investigate the risk of Fucus radicans, being negatively impacted by future climate changes and to use the new knowledge produced in the project in management and conservation plans of fucoids in the Baltic Sea.

Blue mussels (Mytilus edulis and M. trossulus)
Baltic Sea blue mussels, Mytilus edulisand M. trossulus, are taxonomicallycomplicated being a mixture of genes from two separatelineages of blue mussels that likely invaded the Atlantic from the Pacific Sea at two different occasions. Mytilus edulis is established all along the European Atlantic coast while in the Baltic Sea genes of M. trossulus predominate (introgressed with M. edulis genes). In BaltGene we develop species-specific genetic markers that will be used to address basic research questions about the role of hybridization and evolution in these species, as well as for management purposes.

Cockle (Cerastoderma lamarcki and C. edulis)
Cockles are dominant bivalves in shallow sandy bottoms of most of the Baltic Sea as well as along all the Atlantic coasts of Europe. They are commercial harvested, but still more, cockles are important food items for fishes, crustaceans and birds. Not much is known about the genetics of the cockles of the Baltic Sea. BaltGene will investigate the genetic structure of the two cockle species, assessing the degree of local adaptation and among-population connectivity. This knowledge is important for management and conservation of local stocks of these species.

Cod (Gadus morhua)
Cod is a main predatory fish in the Baltic Sea that has a key-role in the Baltic Sea ecosystem. Its commercial importance has been in focus since the large cod fisheries during the 1980-ies. The Baltic stocks of cod are genetically distinct from stocks right outside the Baltic Sea (Öresund and Kattegat). In BaltGene our focus is on the adaptive value of these differences. In collaboration with researchers in Norway we map the occurrence of adaptive genetic variation and trace the importance in local adaptation of cod stocks.

Herring (Clupea harengus)
The herring is the most important commercial fish species in the Baltic Sea. It occurs in all parts of Baltic Sea, and earlier genetic studies have revealed very little genetic differentiation between stocks in different parts of the Baltic. However, only very limited number of markers have been studied so far, and hence, possible cryptic structuring of the different stocks is an possibility that has been little explored so far. One of the aims of the BALTGENE project is to study the genetic structuring and diversity of Baltic herrings in more detail to uncover possible cryptic structuring and stocks.

Whitefish (Coregonus lavaretus)
Pike (Esox lucius)
Perch (Perca fluviatilis)

Threespine stickleback (Gasterosteus aculeatus)

The threespine stickleback is a small marine fish which occurs throughout the Baltic Sea region. The species has become an interesting model for studies in evolutionary genetics and bioogy because it's genome has been sequenced. In the Baltgene project, the threespine stickleback features in studies which aim to understand causes behind the patterns and extent of genomic diversity in the whole Baltic scale. In other words, the aim of the studies is to investigate to which degree the genetic diversity in sticklebacks can be explained by adaptation to local environmental conditions, and to which degree by random process of genetic drift. To this end, samples of threespine sticklebacks collected along the entire coast of Baltic Sea are analyzed for genetic variability in large number of genes and genetic markers.

Sea trout (Salmo trutta m. trutta)
Sea trout is an anadromous species returning to rivers for reproduction. Its many populations are exploited and heavily enhanced by release of alevins and smolts to rivers. Samples will be collected from representative areas of the Baltic. Genetic polymorphism will be compared among sea trout populations and implications for management will be worked out.