Sardines ("pilchards") are a nutrient-rich, small, oily fish widely consumed by humans and as forage fish by larger fish species, seabirds and marine mammals. Sardines are a source of omega-3 fatty acids. Sardines are often served in cans, but can also be eaten grilled, pickled, or smoked when fresh.
The term sardine was first used in English during the early 15th century, and may come from the Mediterranean island of Sardinia, around which sardines were once abundant.
The terms sardine and pilchard are not precise, and what is meant depends on the region. The United Kingdom's Sea Fish Industry Authority, for example, classifies sardines as young pilchards. One criterion suggests fish shorter in length than are sardines, and larger ones pilchards. The FAO/WHO Codex standard for canned sardines cites 12 species in the Order of Clupeiformes that may be classed as sardines, including Atlantic herring (Clupea harengus), and brisling sardine (Sprattus sprattus); FishBase, a comprehensive database of information about fish, calls at least six species just 'pilchard', over a dozen just 'sardine', and many more with both those two basic names qualified by various adjectives.
Sardines are commercially fished for a variety of uses: bait, immediate consumption, canning, drying, salting, smoking, and reduction into fish meal or fish oil. The chief use of sardines is for human consumption, fish meal is used as animal feed, while sardine oil has many uses, including the manufacture of paint, varnish, and linoleum.
Nutrition
Sardines are rich in vitamins and minerals. A small serving of sardines once a day can provide up to 13% of the RDA (recommended daily allowance) value of vitamin B2, roughly one-quarter of the RDA of niacin, and about 150% of the RDA of vitamin B12. All B vitamins help to support proper nervous system function and are used for energy metabolism, or converting food into energy. Also, sardines are high in the major minerals such as phosphorus, calcium, potassium, and some trace minerals such as iron and selenium. Sardines are also a natural source of marine omega-3 fatty acids, which reduce the occurrence of cardiovascular disease. Recent studies suggest the regular consumption of omega-3 fatty acids reduces the likelihood of developing Alzheimer's disease and can even boost brain function. These fatty acids may also help lower blood sugar levels a small amount. They are also a good source of vitamin D, calcium, and protein.
Because they are low in the food chain, sardines are very low in contaminants, such as mercury, relative to other fish commonly eaten by humans.
Canned sardines
Sardines are canned in many different ways. At the cannery, the fish are washed, their heads are removed, and then smoked or cooked, either by deep-frying or by steam-cooking, after which they are dried. They are then packed in either olive, sunflower, or soybean oil, water, or in a tomato, chili, or mustard sauce.
Canned sardines in supermarkets may actually be sprat (such as the “brisling sardine”) or round herrings. Fish sizes vary by species. Good-quality sardines should have the head and gills removed before packing. They may also be eviscerated before packing (typically the larger varieties). If not, they should be purged of undigested or partially digested food or feces by holding the live fish in a tank long enough for them to empty their digestive systems.
Sardines are typically tightly packed in a small can which is scored for easy opening, either with a pull tab like that on a beverage can or with a key attached to the bottom or side of the can. Thus, it has the benefit of being an easily portable, nonperishable, self-contained food.
The close packing of sardines in the can has led to their metaphorical use in the term "packed like sardines" to describe any situation where people or objects are crowded tightly together such as in a bus or nightclub. It has also been used as the name of a children's game, where one person hides and each successive person who finds the hidden one packs into the same space until only one is left out, who becomes the next one to hide.
Around the world
Australia
There is a sardine fishery in Australia harvesting the species Sardinops sagax. The species occurs—in temperate waters, from inshore waters to the edge of the continental shelf, down to depths of about 200 metres—south from Hervey Bay, in Queensland to Shark Bay in Western Australia. Although there is a market for fresh fish for human consumption and fish processed as canned pet food, increasingly, it is mainly used to feed Southern bluefin tuna held in sea cages.