[veidelis]

What I've had heard so far about cod's troubles in the Baltic sea is that it's not salty enough for them. For cod to reproduce, their eggs need a certain salinity so that they swim to the right depth after they are spawned.

Here's an article in Latvian news site about it - https://nra.lv/neatkariga/intervijas/481931-mencu-zveja-balt...