Pleuronectidae

Baltic flounder

Platichthys solemdali

Neritic eggs sink straight toward the seabed

• Temperate
• Northern Hemisphere
• Local endemic species
• Restricted distribution
• Brackish fish
• Atlantic Ocean
• Medium
• Temperate fish

The Baltic flounder (Platichthys solemdali) is a species of flatfish endemic to the Baltic Sea, where it is the only known endemic fish species. It is sympatric with the closely related European flounder (P. flesus), which it looks identical to and can only be distinguished from via genetic analysis. However, both have very different spawning behaviors and habitat requirements; the strongly migratory European flounder requires a minimum level of salinity and spawns in the pelagic zone where its eggs are carried by the waves, whereas the largely resident Baltic flounder is more tolerant of salinity decreases and spawns in shallow neritic areas where its eggs sink to the seabed.