The effects of elevated carbon dioxide concentrations on the metamorphosis, size, and survival of larval hard clams (Mercenaria mercenaria), bay scallops (Argopecten irradians), and Eastern oysters (Crassostrea virginica)

We present experiments that examined the metamorphosis, growth, and survivorship of larvae from three species of commercially and ecologically valuable shellfish ( Mercenaria mercenaria , Argopecten irradians , and Crassostrea virginica ) at the levels of CO 2 projected to occur during the 21st century and beyond. Under CO 2 concentrations estimated to occur later this century (~66 Pa, 650 ppm), M. mercenaria and A. irradians larvae exhibited dramatic declines (>50%) in survivorship as well as significantly delayed metamorphosis and significantly smaller sizes. Although C. virginica larvae also experienced lowered growth and delayed metamorphosis at ~66 Pa CO 2 , their survival was only diminished at ~152 Pa CO 2 . The extreme sensitivity of larval stages of shellfish to enhanced levels of CO 2 indicates that current and future increases in pelagic CO 2 concentrations may deplete or alter the composition of shellfish populations in coastal ecosystems.