Foods like salmon, lobster, and shrimp, are often categorized as “seafood.” But how might you classify these foods when including a freshwater fish, such as trout? Consider the term aquatic foods (also called blue foods), which include any animals, plants, and microorganisms that originate in bodies of water. Examples are:
Aquatic foods can be farmed or wild-caught, and are sourced from inland waters like lakes, rivers, and wetlands; coastal areas like estuaries, mangroves, or near-shore; and marine or ocean waters. Despite currently being an important contribution to healthy diets for billions of people globally, aquatic foods are often undervalued nutritionally because their diversity tends to be restricted to protein or energy value, or framed as a monolithic category of “seafood or fish.” [1] However, there is broad diversity of aquatic foods produced throughout the world and available during every season. Currently, wild fisheries harvest over 2,370 species and aquaculture growers farm approximately 624 species.
Because aquatic foods are so nutrient rich, food technologists have innovated methods to create processed fish products, including fish powders for infants, fish wafers as a snack, and fish chutneys.
Certain aquatic animal foods are a major dietary source of two polyunsaturated omega-3 fatty acids (PUFAs)—docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). These fatty acids are initially produced by certain types of algae, which are then eaten by aquatic animals so that the fats accumulate in their tissues or organs. Omega-3s are found in all aquatic foods, but particularly in the fatty tissue of oily fish like salmon and mackerel, the liver of lean white fish like cod and halibut, and the blubber or thick layer of fat under the skin of marine animals like seals and whales. Smaller amounts are also found in crustaceans, bivalves, and cephalopods. Supplements of fish oil, algal oil, and krill oil also contain DHA and/or EPA. Much of the research on aquatic foods and human health focuses on these omega-3s.
Research has also found that swapping red and processed meat with fish and seafood can lower the risk of diseases and premature death. One reason may be differences in types of fat: mostly saturated fat in red meat versus unsaturated fat in seafood. Data from six U.S. cohort studies found that higher intakes of red meat and processed meat were associated with an increased risk of cardiovascular disease and early death, whereas fish was not. Research from a large Danish cohort study found that replacing red and/or processed red meat with fish or poultry lowered the risk of type 2 diabetes and early death.
Modern production of aquatic foods can be split into two different sectors: wild capture and aquaculture. Wild capture production involves harvested wild fish and other aquatic species from the ocean and freshwater sources. Aquaculture is the practice of farming aquatic plants and animals.
In general, the production of any animal-based food tends to have higher greenhouse gas emissions than the production of plant-based foods, with red meat (especially beef and lamb) standing out for its disproportionate impact. However, the production of aquatic foods (through both wild capture and aquaculture) not only produces fewer greenhouse gas emissions and uses less land than red meat production, but many aquatic animal foods also have less environmental impact than poultry production. That said, beyond emissions and land use, it is important to consider where and how aquatic foods are produced, since environmental as well as social and economic impacts can vary widely in both wild capture and aquaculture sectors.
The percentage of wild marine fisheries classified as “overfished” has steadily increased over the past few decades. According to an assessment by the Food and Agriculture Organization of the United Nations, the fraction of fish stocks that are within “biologically sustainable” levels decreased from 90% in 1974 to just under 66% in 2017. Beyond the challenges that overfishing presents for food security and human health, commercial fishing at current scales can also contribute to:
Aquaculture is emerging to fill gaps in seafood supply from reductions in existing wild fish stocks. Today, aquaculture represents the world’s fastest growing food production industry, based largely in Asia (China, India, Vietnam, Bangladesh), Europe (Norway), and increasingly in Africa (Egypt). Despite its promise, aquaculture must be done responsibly. For example, insufficiently regulated aquaculture can result in both environmental stressors—such as freshwater use and nitrogen and phosphorus emissions—as well as negative interactions with wild fishery populations through the spread of disease, overuse of antibiotics, escaped species.
In summary, sustainably and equitably achieving the human health benefits of increased aquaculture production will require policies and technologies that minimize impacts on surrounding ecosystems, industries, and communities.
Aquatic foods are a diverse category of nutrient-dense, protein-rich foods that can also be a healthful animal-based alternative when looking to cut down on red meat or other land-sourced animal foods. Misconceptions exist, such as having a strong off-putting odor (fresh fish should not smell!) or higher cost than other animal protein foods, which may deter people from choosing aquatic foods. However, many aquatic foods are a major source of omega-3 fatty acids and various nutrients that are helpful in the prevention and treatment of cardiovascular disease, and that are vital for normal fetal development. They can also be delicious and satisfying, and incorporated into many meals like salads, stews, sandwiches, and main courses. Here are some recipes and ideas for cooking with aquatic foods.
