General Characteristics And Habits
Sardines have a flat body which is covered with large, reflective, silvery scales. In the middle of their belly, they have a set of specialized scales, known as scutes, which are jagged and point backwards. Having very small teeth or no teeth at all, sardines eat plankton, which they filter from the water through their gills. While numerous species of sardines live off the coasts of India, China, Indonesia, and Japan, single sardine species dominate in areas like the English Channel and the California coast. Sardines are basically a warm-water fish, but occur as far north as Norway.
Schools, or shoals, of sardines swim near the water surface and are primarily marine, although some live in freshwater. Most species are migratory; in the Northern Hemisphere, for example, they migrate northward in the summer and southward in the winter. During spring and summer, they spawn. After doing this, the young commonly move closer to the shore to feed. The young sardines eat plant plankton (or phytoplankton), while adults eat animal plankton (zooplankton). All sardine species are important prey for larger fish.