Twait shad are silvery, sometimes with a bronzy tinge, and there are a distinctive row of six to ten large dark spot just behind the gill cover though these may fade when the fish is dead. The adult length is typically . The twait shad is found in most of Europe and all countries bordering the Mediterranean Sea. "Alosa fallax" has a similar lifecycle to "A. alosa" (allis shad). They are known to live in sympatry. Some studies have suggested "A. fallax" and "A. alosa" species can hybridize. They are anadromous species, like many other species in the genus "Alosa". However, some
Herring as food in Europe, and early in the twentieth century their study was fundamental to evolution of fisheries science. These oily fish also have a long history as an important food fish, and are often salted, smoked, or pickled. Herring are very high in the long-chain Omega-3 fatty acids EPA and DHA. They are a source of vitamin D. Water pollution influences the amount of herring that may be safely consumed. For example, large Baltic herring slightly exceeds recommended limits with respect to PCB and dioxin, although some sources point out that cancer-reducing effect of omega-3 fatty acids is statistically stronger than