Just saw my DR. yesterday and she said to watch out for shellfish like shrimp and lobster (bottom-dwellers?) as well as eating any big fish that eat other fish b/c of high mercury levels. You can have your mercury levels checked with a blood test. As you may know, tuna has alot of mecury.
Yes, you can eat shrimp. A good resource for figuring out which fish to choose is the Natural Resources Defense Council guide to mercury in fish, which you can access at https://www.nrdc.org/health/effects/mercury/guide.asp. The oil in fish provides types of fat that are great for you and baby.
Best,
Megan Tubman, MS, RD
Re: Shrimp? Not sure about shell fish