Aquaculture uses a body of water for the cultivation of plants and animals. (Compare to agriculture, which uses land to cultivate plants and animals.) Ponds, lakes, rivers, and the ocean serve as places to raise and harvest aquatic species.
As with any farming, aquaculture creates jobs for local communities and supports habitat restoration by raising critical plants and animals. Perhaps most importantly, marine aquaculture plays a major role in supplying seafood to a growing global population. Worldwide, about a billion people rely on seafood as their main source of animal protein.
In the United States, farmed oysters, mussels and clams account for about two-thirds of the marine aquaculture production. Shellfish farming begins in a hatchery. Larval shellfish float in seawater for a week or so before settling on a rock, shell or rope to feed on plankton and grow. In one to two years, they reach the right size to harvest and sell to markets, seafood processors, restaurants, and individual consumers.
Shellfish aquaculture is threatened by ocean acidification. More acidic ocean water makes it difficult for shellfish to build their shells. Abalone, corals, sea urchins — anything with hard parts or shells — need carbonate ions to build their calcium carbonate shells. As the seawater becomes more acidic, there are fewer carbonate ions available.
Oysters grown in acidic conditions don’t taste different than other oysters, but they are smaller and misshapen. Research from the Bodega Marine Laboratory at UC Davis shows that when young oysters are exposed to acidic water in their first week of development, after four or five months they haven’t caught up with their counterparts grown under different conditions. Ocean acidification means shellfish may not grow big or healthy enough to harvest, sell and consume.
Shellfish farmers are proactively adapting their practices to sustain aquaculture in a changing ocean. Scientists are measuring the changes to provide farmers with information about how to protect young shellfish and breed resilient populations.
Read about other ocean research by UC Davis scientists.