Table S1.
Summary of the samples collected and analyzed in this study
| Location | Code | N | Coordinates | Date | % Spawning | Putative ecotype |
| Gullmaren (NS)* | GUL | 4 | 58.17N, 11.30E | February 2002 | 25 | Pelagic |
| Kattegat (NS) | KAT | 20 | 57.25N, 12.11E | September 2009 | Not recorded | Pelagic |
| Barsebäck (TZ)* | BAR | 22 | 55.45N, 12.53E | April 2003 | 4 | Pelagic |
| Dabki (BS)* | DAB | 24 | 54.45N, 16.30E | May 2003 | 4 | Pelagic |
| Gdynia (BS)* | GDY | 24 | 54.45N, 18.30E | May 2003 | 4 | Pelagic |
| Bornholm (BS)* | BOR | 22 | 55.42N, 16.11E | March 2003 | 100 | Pelagic |
| Latvian Sea (BS)* | LAT | 24 | 56.25N, 19.44E | April 2003 | 69 | Pelagic |
| Irbe (BS)* | IRB | 24 | 57.44N, 22.22E | May 2003 | 75 | Demersal |
| Öland (BS) | ÖLA | 24 | 57.14N, 17.06E | April to June 2004 | 92 | Demersal |
| Kvädöfjärden (BS)* | KVÄ | 24 | 58.01N, 16.46E | May 2003 | 58 | Demersal |
| Hanko (BS) | HAN | 22 | 59.82N, 22.99E | June 2012 | Not recorded | Demersal |
| Åland (BS)* | ÅLA | 24 | 60.09N, 19.42E | May to June 2003 | 8 | Demersal |
| Helsinki (BS)* | HEL | 24 | 60.15N, 25.30E | May 2003 | 0 | Demersal |
N, sample size; % Spawning, percentage of the sampled individuals that were ready to spawn (with running roe and sperm) at the time of collection. Locations where more than 90% of sampled individuals were ready to spawn are considered as reference demersal (Öland) and pelagic (Bornholm) populations.
*
Samples from these locations were originally obtained by Florin and Höglund (15).