Anchovies are small, bony fish in the order Clupeiformes, a large group that also includes herring, salmon, and trout. Anchovies are in the family Engraulidae, and all of the more than 100 species are in the genus Engraulis. Anchovies are predominantly marine fish, but are occasionally found in brackish waters and even in freshwater. Species of anchovies are found in the Mediterranean Sea, Black Sea, European Atlantic coastal waters, and the Pacific coasts of Peru and Chile.
Anchovies are about 4-8 in (10-20 cm) long, with smooth scales, and soft fins. They live in schools made up of many thousands of individuals, often grouped according to size. Anchovies come to surface waters during the spawning season from May-July. Their eggs float on the surface of the water and hatch in 3-4 days. Anchovies swim with their mouths open, and feed on plankton, small crustaceans, and fish larvae. When food is scarce, anchovies take turns swimming at the front of their school, where they are more likely to encounter the best food. When a school of anchovies senses danger, the fish swim together to make a tight ball in which the fish on the inside are more protected, while those on the outer part have a greater chance of being consumed. Anchovies are usually caught by fishermen at night—lights on the boat serve as a lure.
Anchovies are extremely important as a food source for many predators. Examples of anchovy predators include sharks, yellowtail, salmon, tuna, pelicans, terns, seals, sea lions and dolphin. In addition, anchovy are harvested by humans.
In Peru, the anchovy known as anchovetta (Engraulis ringens ), is economically important as a source of fish meal and fertilizer. In 1970, the Peruvian anchovetta fishery yielded about 12 million tons of fish, but this crashed to less than 2 million tons in most years between 1973-1987. The collapse of the fishery was likely due to excessive harvesting, although oceanographic and climatic changes associated with warm-water El Niño events may have also played a role. After this time, there was a slow recovery of the anchovetta stocks to about 4 million tons a year. Other species of anchovy (such as E. encrasicolus ) are fished in smaller numbers, canned in oil and salt, and sold as a delicacy (these are the tiny fish on pizza and in the dressing for Caesar salad). Other species of anchovy are used as fish bait or are added to pet food and livestock feed.