Anyone else have problems taking vitamins?

Actually its higher in deep water fish because there is more mercury in the water at depth. Has nothing to do with predator fish.
Also fish that live longer are worse for mercury simply because of their exposure.

*claps*

I dropped an unless from that sentence. I meant not a problem unless you are eating a lot of predatory fish like shark.
Some of the very highest mercury levels are in top of the food chain pelagics like shark, albacore tuna, swordfish etc.
These are the worst for mercury content:
HIGH MERCURY
Bluefish
Grouper*
Mackerel (Spanish, Gulf) Sea Bass (Chilean)* Tuna (Canned Albacore) Tuna (Yellowfin)*
HIGHEST MERCURY
Mackerel (King) Marlin*
Orange Roughy* Shark* Swordfish* Tilefish*
Tuna (Bigeye, Ahi)*
Most of them are not deep water fish.

Both these deficiencies are associated with strict vegan diets. D deficiency can also be associated with obesity and alcoholism. Eating right and spending @ a hour out doors is enough for most people.

Mercury is really a problem with a high diet of predatory fish. Shrimp, salmon, catfish, tilapia and some types of tuna do not have very high levels of mercury. Mercury becomes a problem if you are eating a lot of top of the food chain fish, sushi daily, lots of shark or albacore tuna you shouldn't have a problem. A lot of the high mercury fish are also hard on the pocketbook Albacore tuna, shark, swordfish, etc. Most farm raised fish are not high in mercury.

When you eat farmed fish you lose a lot of the benefits you get from eating fish. Farmed fish are fed pellets made from grains (mostly corn), and fishmeal, and that causes them to store more Omega 6 fatty acids than wild caught fish. They are also fed antibiotics because there are huge issues with diseases and parasites from having such a huge biomass crammed into a usually much smaller space than they ever would be in the wild. In the case of salmon, they add dye to the food so it gets its famous pink color. In the wild salmon gets that color from krill. They also threaten the environment by introducing exotic species to new areas. A few of these fish will escape, and threaten the native species. I've seen farmed fish facilities, and I work as a fisheries observer in Alaska on the commercial fishing boats. You are better off with wild fish, just eat aim to eat smaller fish that are at the bottom or middle of the food chain.

With our current fishing levels, top level ocean predators will be a thing of the past soon. Overfishing is rampant, even in the US. Bluefin tuna world wide will most likely go extinct in my lifetime because they are being harvested before they are old enough to spawn.

http://www.montereybayaquarium.org/cr/SeafoodWatch/web/sfw_factsheet.aspx?gid=49

http://www.huffingtonpost.com/sea-to-table/is-farmed-fish-really-the_b_3455436.html