https://www.fda.gov/food/metals-and-your-food/mercury-levels-commercial-fish-and-shellfish-1990-2012
Raw data here: https://www.fda.gov/media/101237/download
Doesn’t seem to be much mercury at all in salmon.
I was eating wild Alaskan salmon daily. Had my blood checked for heavy metals after more than a year. Found high levels of arsenic (not harmful) but no other heavy metals. You can’t generalize from N=1 but that was my experience.