Questions & Answers from the FDA/EPA Advice on What Pregnant Women and Parents Should Know about Eating Fish, FDA
Albacore has more omega-3 fat per ounce but since it comes from a larger species of tuna, it also has more mercury. Chunk light, on the other hand, comes from a smaller species of fish and has less mercury and omega-3 fat.
The Food and Drug Administration and EPA recommend that women who may become pregnant, pregnant women, nursing moms and young children eat up to 12 ounces (2 average meals) of lower-mercury fish and shellfish each week. Since albacore ("white") tuna has more mercury than light tuna, when choosing your 2 fish, you can safely eat up to 6 ounces of albacore tuna each week (which is a healthy serving of tuna for one average meal).
Use the chart to help you choose which fish to eat each week. Eating a variety of fish is better for you and your child than eating the same type every time.