You can also visit the Natural Resources Defense Council  mercury calculator based on your weight and specific seafood you have consumed.

Highest Mercury

AVOID Eating

Grouper
Marlin
Orange Roughy
Tilefish
Swordfish
Shark
Mackerel (king)

High Mercury

Eat no more than three 6-oz servings per month

Bass saltwater
Croaker
Halibut
Tuna (canned, white albacore)
Tuna (fresh bluefin, ahi)
Sea trout
Bluefish
Lobster (American/Maine)

Lower Mercury

Eat no more than six 6-oz servings per month

Carp
Mahi Mahi
Crab (dungeness)
Snapper
Crab (blue)
Herring
Crab (snow)
Monkfish
Perch (freshwater)
Skate
Cod
Tuna (canned, chunk light)
Tuna (fresh Pacific albacore)

Lowest Mercury

Enjoy two 6-oz servings per week

Anchovies
Butterfish
Calamari (squid)
Caviar (farmed)
Crab (king)
Pollock
Catfish
Whitefish
Perch (ocean)
Scallops
Flounder
Haddock
Hake
Herring
Lobster (spiny/rock)
Shad
Sole
Crawfish/crayfish
Salmon
Shrimp
Clams
Tilapia
Oysters
Sardines
Sturgeon (farmed)
Trout (freshwater)

** Chart obtained from the Natural Resource Defense Council (NRDC); data obtained by the FDA and the EPA.