MULLET, the name of two different kinds of fishes, dis tinguished as red mullets and grey mullets.
Red mullets (genus Mullus) are marine fishes, with two short dorsal fins, the first composed of feeble spines, the second of branched rays. The body is covered with large thin scales. The anterior profile of the head slopes downwards to the small mouth, which has small, feeble teeth. There are two sensitive barbels on the lower jaw, generally laid back in a groove, but capable of erection when needed. About 4o species are known, chiefly from the tropical and subtropical parts of the Indo-Pacific ocean. In European waters two species occur (Mullus surmuletus and M. barbatus). The former, in addition to the general red colour, has three to five bright yellow bands along the sides from head to tail ; these are absent in the other form. The striped form is usually found on the coasts of England, while in the Mediter ranean both kinds occur.
The largest red mullets weigh only two or three pounds. They are ground-feeders, using their barbels in discovering their food, which consists of crustacea, worms, and, in the larger species, of small fishes. Their brilliant colours are simple and evanescent ; in many, red prevails. All the species are esteemed as food, but none equals the European species. During winter the fish retire into deep water, late in spring and during summer they approach the coasts and enter even brackish water, but they do not come towards the shore to breed. At Naples they spawn from May to August ; their ova are buoyant and transparent.
The grey mullets form a very distinct family, Mugilidae. They enter brackish water, live always close to the shore, and some of the tropical forms inhabit the fresh water without, however, pene trating far inland. Their body is elegantly formed, wedge-shaped,
and covered with scales of moderate size. The anterior of the two short dorsal fins is composed of four stiff spines. The caudal fin is strong and bilobed. The mouth is narrow, transverse in the true Mugil, and without, or with but feeble, teeth. About 7o different species are known, from most parts of the temperate and tropical zones; they swim in small schools and are abundant wherever they occur. The commonest British species is Mugil cephalus; found also on both coasts of North America and else where. Some of the fresh-water grey mullets of the tropics have been formed into a separate genus, Agonostoma.
Grey mullets may grow to a weight of 1 o or 12 pounds. Those in which distinct teeth are developed feed on small aquatic ani mals, while the diet of those without teeth consists of animalcules, confervae, or minute organic debris mixed with the mud and sand, which they swallow in large quantities. To prevent the gills from being clogged by sand or mud, each branchial arch is pro vided with a series of closely set gill-rakers, each series fitting into the series of the adjoining arch; they constitute a sieve permitting the passage of the water, while retaining other substances. Grey mullets are plainly coloured, generally greenish on the upper parts and more or less silvery on the side. They are wholesome food. Grey mullets are cultivated in fish farms in Italy.