Now I'm pretty ignorant, but I'm going to take a crack at these #'s:

  >Sure.  According to the USDA Nutrient Database, raw farm-raised salmon
>has:
>
>20:5 n-3 = 0.618
>22:6 n-3 = 1.293

Ok, farm-raised salmon has a total of about 1.9 grams of EPA per 100 gram
serving.

>   Tuna, 100 grams, fresh, raw:
>
>   20:5 n-3 = 0.283
>   22:5 n-3 = 0.125
>   22:6 n-3 = 0.890

Fresh raw tuna has a total of about 1.3 grams of EPA per 100 gram serving.

>   Salmon, 100 grams, fresh, raw:
>   20:5 n-3 = 0.321
>   22:5 n-3 = 0.287
>   22:6 n-3 = 1.115

Fresh, raw salmon has about 1.7 grams of EPA per 100 gram serving.

Since fresh salmon has lower(much lower, I'd guess) omega-6, *and* it is
better balanced in its omega-3 composition, then raw salmon is best. But to
me it doesn't look like raw tuna(what about canned?) is that much worse
than raw salmon, and farm salmon is still better than nothing.

I'm guessing that I'm misinterpreting the #''s above. But I ain't gonna
learn if I don't raise this stuff.

Dave