Some marine species are well adapted to the Baltic conditions and occur in high population densities, allowing for fishing opportunities with high commercial value. Cod (Gadus morhua), Baltic herring (Clupea harengus membras), and sprat (Sprattus sprattus) comprise the large majority of the Baltic fish communities in terms of biomass and numbers (see figure below on spawning stock biomass). The marine fish species such as cod, sprat, flounder (Platichthys flesus), plaice (Pleuronectes platessa), dab (Limanda limanda), turbot (Psetta maxima) and brill (Scophthalmus rhombus) prefer more saline areas and therefore these species are more abundant in the southern Baltic and/or the Baltic proper.
Spawning stock biomass (SSB) of herring cod and sprat in the Baltic Sea 1980-2012. Source: ICES.
Baltic herring (Clupea harengus membras). Photo: Riku Lumiaro/Finnish Environment Institute.