The environment is changing as increasing carbon dioxide is released into the atmosphere from the burning of fossil fuels. The atmosphere is warming and the oceans are absorbing more carbon dioxide and becoming more acidic. This reduction in ocean pH is known as ocean acidification. Calcium carbonate is abundant in the oceans as organisms such as shellfish produce protective shell structures. The amount of carbonate available in the oceans under ocean acidification will be reduced, limiting the ability of organisms to produce protective shells. This project will investigate the influence of ocean acidification and warming on the ability of three shellfish species to produce protective shells. Commercially available shellfish will be cultured under future ocean acidification and warming conditions in a laboratory. Shells will be tested for physical and material properties to understand the vulnerability of shells to fracture under changing environments and predation. This project will determine how molluscs produce their calcium carbonate shells, identifying the carbon source and route for shell production under changing climates. This knowledge will enable accurate predictions of the vulnerability of aquaculture to ocean acidification and warming. Feeding experiments and harvesting protocols will be developed to alleviate potential damage to shells during aquaculture for a more resilient, sustainable and more economical shellfish culture.