All I ever want to eat is tuna sandwiches...

[Anonymous]

OP -- I think you are doing okay, but if you can, perhaps you could cut it back to twice a week.

Here is what I found on the Mayo clinic website (I find them to be one of the more trusted websites when it comes to health issues):

Seafood
Seafood can be a great source of protein and iron, and the omega-3 fatty acids in many fish can help promote your baby's brain development. In fact, a British study suggests that skimping on seafood during pregnancy may contribute to poor verbal skills, behavioral problems and other developmental issues during childhood. However, some fish and shellfish contain potentially dangerous levels of mercury. Too much mercury may damage your baby's developing nervous system.

The bigger and older the fish, the more mercury it may contain. The Food and Drug Administration (FDA) encourages pregnant women to avoid:

Swordfish
Shark
King mackerel
Tilefish


So what's safe? Some types of seafood contain little mercury. Although concerns have been raised about the level of mercury in any type of canned tuna, the FDA says you can safely eat up to 12 ounces a week (two average meals) of:

Shrimp
Canned light tuna (limit albacore tuna and tuna steak to no more than 6 ounces a week)
Salmon
Pollock
Catfish
To avoid ingesting harmful bacteria or viruses, avoid raw fish and shellfish — especially oysters and clams — and anything caught in polluted water. Refrigerated smoked seafood is also off-limits, unless it's an ingredient in a casserole or other cooked dish.

Most fish should be cooked to an internal temperature of 145 F. The fish is done when it separates into flakes and appears opaque throughout. Cook shrimp, lobster and scallops until they're milky white. Cook clams, mussels and oysters until their shells open. Discard any that don't open.