Fig. 1.

Map of the sampling locations showing modeled mean bottom salinity in the Baltic Sea from Bendtsen et al. (62). Areas theoretically suitable for pelagic spawning are colored in green, yellow, and red. Locations are color-coded based on expected spawning behaviors. ÅLA, Åland Archipelago; BAR, Barsebäck; BOR, Bornholm Basin; DAB, Dabki; GDY, Gdynia; GUL, Gullmaren; HAN, Hanko (Western Gulf of Finland); HEL, Helsinki (Gulf of Finland); IRB, Irbe Strait; KAT, Kattegat; KVÄ, Kvädöfjärden; LAT, Latvian Sea; and ÖLA, Öland Island. More than 90% (Table S1) of samples from BOR (pelagic habitat) and ÖLA (demersal habitat) were ready for spawning at the time of capture, hence these locations were used as reference pelagic and demersal populations, respectively.