Fish as food

Humans catch and consume many species of fish in nearly every region of the world.

Fish meat is a vital dietary source of protein and various essential nutrients. While the English language lacks a specific culinary name for fish meat, unlike "pork" for pig, it remains a global food staple. In many contexts, the term "seafood" is used more broadly. This term covers fish as well as shellfish, which include molluscs, crustaceans, and echinoderms. Fish are part of a massive biological group. Scientists have described over 32,000 species of fish. This makes them the most diverse group of vertebrates on Earth.

Preparing fish involves many different culinary techniques. Some people eat fish raw, such as in the Japanese style known as sashimi. Other methods involve curing the meat through marinating, pickling, or smoking. Common cooking methods include baking, frying, grilling, steaming, or poaching. Poaching involves cooking the fish in a liquid called a court-bouillon. Many traditional preservation methods are still used today. Even when they are no longer necessary for safety, people use them to improve taste and texture. The texture of fish is relatively delicate compared to land animals. This is because fish have short fibers and very little connective tissue. Fish contain only about 3% connective tissue by weight, while land animals have about 15%.

Fish can be categorized into several distinct groups based on their fat content. Whitefish, such as haddock or Alaska pollock, contain very little fat, usually less than 1%. Oily fish, such as sardines or Atlantic herring, contain between 10% and 25% fat. This higher fat content provides fat-soluble vitamins like A, D, E, and K. It also provides essential fatty acids. Shellfish is another major category used for food. These include various molluscs and crustaceans. People often group fish by their flavor and texture as well. Some species offer a mild flavor and delicate texture, like flounder or hardshell clams. Others provide a full flavor and firm texture, such as tuna or lobster.

Global consumption patterns have changed significantly over the last several decades. In 1961, Europe, Japan, and the United States accounted for 47 percent of total food fish consumption. By 2015, this share dropped to approximately 20 percent. During that same period, global food fish consumption grew at an average annual rate of 3.2 percent. This rate outpaced the global population growth rate of 1.6 percent. In 2015, the world consumed a total of 149 million tonnes of food fish. Asia consumed more than two-thirds of this total, which equals 106 million tonnes. This represents a per capita consumption of 24.0 kg in Asia. In contrast, Oceania and Africa consumed the lowest shares of the global total. This shift is linked to the growing role of Asian countries in fish production.

Fish is a highly significant source of nutrition for much of the human population. On a global scale, fish products provide an average of 34 calories per capita per day. However, their importance goes beyond simple energy. Fish provides high-quality, easily digested animal proteins. A 150g portion of fish can provide 50 to 60 percent of an adult's daily protein requirement. This is especially critical in densely populated countries or small island developing States (SIDS). Oily fish are particularly beneficial because they contain long-chain omega-3 fatty acids. Eating oily fish once per week is often recommended. These fatty acids may help reduce systemic inflammation and lower the risk of cardiovascular disease.

Despite these benefits, there are notable risks and hazards associated with eating fish. Some species possess natural toxins as a defense against predators. The fugu pufferfish is a famous example. It contains a lethal dose of tetrodotoxin in its internal organs.

In Japan, only licensed chefs who pass a national examination may prepare fugu. Other risks include ciguatera poisoning, which occurs from eating large fish like grouper or barracuda in warm tropical waters. Scombroid poisoning can also happen if oily fish like tuna or mackerel are not refrigerated properly. Furthermore, shellfish are filter feeders. They can accumulate biotoxins from microscopic algae, such as domoic acid or saxitoxin. These toxins can cause serious illness or even death.

Safety also involves managing physical hazards and biological sensitivities. Fish bones are a common cause of airway obstruction. In 1998, the United Kingdom reported about 4,500 accidents involving choking on fish. Additionally, some people suffer from seafood allergies. These allergies occur when the immune system overreacts to allergens in fish or shellfish. Reactions can happen from eating the food or even breathing in vapors during cooking. The most severe reaction is anaphylaxis, which is a medical emergency. This condition requires immediate treatment with epinephrine to prevent severe physical symptoms.