Clam Aquaculture Production, Farm-gate Values and Prices in the United States

Estimates of U. S. aquaculture production are based on data (in millions) released by NOAA Fisheries. Finfish include baitfish, catfish, salmon, striped bass, tilapia, and trout. The species included under shellfish are clams, crawfish, mussels, oysters, and shrimp. Miscellaneous species include ornamental fish, alligators, algae, aquatic plants, eels, scallops, and others. 

There were more than 300 farms growing various clam species in the U.S. (2018 Census of Aquaculture).
U.S. farmed hard clams are a smart seafood choice because they are sustainably grown and harvested under U.S. state and federal regulations (https://www.fisheries.noaa.gov/species/blue-mussel). Hard clams are farmed mostly in Florida, Virginia, New Jersey, Massachusetts, Connecticut and other states. Geoduck and Manila clams are mostly farmed in Washington. 

Source of raw data: NOAA Fisheries. 
Legend: $/pound1 = farm-gate values ($/yr) / total production (lb/yr); $/pound2 =  $/pound1 / CPI.
Read more at http://coastal.msstate.edu/aquaculture-production