PERCIFORM

any member of the order Perciformes, a group of bony fishes with more than 6,000 species placed in about 150 families. The group includes some of the most important food and game fishes, such as the tunas, mackerels, marlins, perches, and sea basses. Most perciforms range from 30 to 250 cm (about 1 to 8 feet) in length, but the smallest species, the freshwater goby of the Philippines, measures barely half an inch in length. By contrast, among the largest perciforms are the bluefin tuna and the Indo-Pacific black marlin, which can reach 680 kg (1,500 pounds) in weight. Perciforms are found all over the world. Among the Antarctic species, which comprise about three-fourths of all Antarctic fishes, the best known is the icefish, noted for its almost transparent appearance. The Indo-West Pacific fishes are also largely made up of perciforms, including the wrasse, goby, and damselfish. Freshwater perciforms include the cichlid, found in India, Africa, and North and South America, and the perch and sunfish families found in North America and Europe. Since the earliest times, perciforms have been an important food source. In Scotland, archaeologists have found evidence of the sea bream being eaten in shell mounds. Nile perches have been found as mummies in Egypt, wrapped up and buried with the dead. Goatfishes (Mullidae) were considered a valuable food by the ancient Romans. In Japan perciforms are eaten raw as sashimi or dried in cakes as kamaboko. Isinglass, used to make jellies and to clarify wine and beer, is obtained from the drums and the threadfins. Leather is provided by the skin of the wolffish, and artificial pearls are made in Japan with guanin, found in the skin of the Japanese cutlass fish. Some perciforms have strange habits. A group of blennies lays eggs in the cavity of a living sponge. The young of the black sea bass are mostly born female, but within five years many of them change into males. Eleven species of the sparids are hermaphroditic at some time or even throughout their lifetimes. Most perciform eggs are fertilized in the water. Many species are protective of their young. Some perciforms form interesting relationships with other marine species. The cleaner fishes, a type of wrasse, remove parasites from inside the mouths of larger predator fishes. The saber-toothed blenny (Aspidontus taeniatus) mimics the cleaner fish but takes a quick bite of fin instead of cleaning. Some fish survive by similar imitations: young tripletails (Lobotidae) turn on their sides and drift like dead leaves. any member of the order Perciformes, a group of bony fishes with more than 6,000 species placed in about 150 families. The order is the largest group of fishes in the world today. Perciform fishes occur in abundance in both marine and freshwater areas of the world, ranging from shallow freshwater ponds to depths of more than 2,300 metres (7,500 feet) in the oceans. Most perciforms are marine fishes, generally found along coastal areas of tropical and temperate regions of the world. The order includes many of the world's most important food and game fishes, such as tunas, mackerels, bonitos, and skipjacks (family Scombridae), billfishes and marlins (Istiophoridae), swordfish (Xiphiidae), sea basses (Serranidae), and carangids (Carangidae), a large family that includes pompanos, jacks, cavallas, and scads. The freshwater food and sport fishes of the perciform order include the sunfishes (Centrarchidae) and the perches and walleyes (Percidae). Many perciforms are popular aquarium fishes. Additional reading Books containing many excellent illustrations of perciform fishes and short accounts of the biology of each group include J.E. Bhlke and C.C.G. Chaplin, Fishes of the Bahamas and Adjacent Tropical Waters, 2nd ed. (1993), a well-illustrated work with keys for identifying species and excellent summaries of the biology of each family; David Starr Jordan and Barton Warren Evermann, The Fishes of North and Middle America, 4 vol. (1896-1900, reprinted 1963); T.C. Marshall, Fishes of the Great Barrier Reef and Coastal Waters of Queensland (1964), contains many colour and black-and-white pictures of perciform fishes; I.S.R. Munro, The Fishes of New Guinea (1967), 1,095 fishes illustrated by photographs, with 76 species in colour; J.L.B. Smith, The Sea Fishes of Southern Africa, 5th ed. (1970), profusely illustrated with many colour plates; J.L.B. and Margaret M. Smith, The Fishes of Seychelles, 2nd ed. (1969), 880 species illustrated, many in colour; A.C. Wheeler, The Fishes of the British Isles and North-West Europe (1969); John E. Randall, Caribbean Reef Fishes, 2nd ed. rev. (1983), contains many fine photographs of perciforms and others; Robert B. Chiasson, Laboratory Anatomy of the Perch, 4th ed. (1991).Other books with information about perciform fishes include Earl S. Herald, Living Fishes of the World (1961, reprinted 1972); N.B. Marshall, The Life of Fishes (1966); and U. Okada, Fishes of Japan, rev. ed. (1965).References pertaining to classification and relationships include W.C. Freihofer, "Patterns of the Ramus Lateralis Accessorius and Their Systematic Significance in Teleostean Fishes," Stanford Ichthyol. Bull. , 8:79-189 (1963); and "Trunk Lateral Line Nerves, Hyoid Arch Gill Rakers, and Olfactory Bulb Location in Atheriniform, Mugilid, and Percoid Fishes," Occ. Pap. Calif. Acad. Sci., no. 95 (1972); W.A. Gosline, "Systematic Position and Relationships of the Percesocine Fishes," Pacif. Sci., 16:207-217 (1962); "The Suborders of Perciform Fishes," Proc. U.S. Natn. Mus., 124:1-78 (1968); and Functional Morphology and the Classification of Teleostean Fishes (1971); P.H. Greenwood et al., "Phyletic Studies of Teleostean Fishes, with a Provisional Classification of Living Forms," Bull. Am. Mus. Nat. Hist., 131:339-455 (1966); D.E. McAllister, "The Evolution of Branchiostegals, and Associated Opercular, Gular, and Hyoid Bones, and the Classification of Teleostome Fishes, Living and Fossil," Bull. Natn. Mus. Can., no. 221 (1968); C.T. Regan, a series of papers on perciform classification in Annals and Magazine of Natural History, series 7, vol. 11 and series 9, vol. 11 (1903-23); and "Fishes," Encyclopaedia Britannica, 14th ed., vol. 9, pp. 305-328 (1929), which still forms the major basis of present perciform classification; D.E. Rosen, "The Relationships and Taxonomic Position of the Halfbeaks, Killifishes, Silversides, and Their Relatives," Bull. Am. Mus. Nat. Hist., 127:217-267 (1964), and with Colin Patterson, "The Structure and Relationships of the Paracanthopterygian Fishes," Bull. Am. Mus. Nat. Hist., 141:357-474 (1969). Classification Annotated classification The classification presented here is mainly that of British ichthyologist P.H. Greenwood and colleagues, published in 1966; it in turn is fundamentally that established by the British ichthyologist C. Tate Regan in 1929. Certain changes have been incorporated, based mostly on characters from the nervous system. All of the features distinguishing the order Perciformes are found in the fishes of the most generalized group, the suborder Percoidei, which contains the sea basses, sunfishes, perches, and fishes of many other families. As the subordinal name implies, the fishes composing it are "percoid," or perchlike in appearance. The fishes in the other suborders have presumably evolved from a percoid-like ancestor, but some have changed so much as to hardly resemble a percoid fish externally. Critical appraisal Classification of perciform fishes will be receiving much more study in the future. Expected changes include removal of some groups from the order, addition of some from other orders, and considerable realignment of many groups within the Perciformes. Evidence suggests removal of Gobioidei to a preperciform position, possibly as a distinct order. The snake-heads (order Channiformes) should likely be returned to the order Perciformes, associated with the anabantoid and luciocephaloid fishes. Particularly difficult problems are the relationships and classifications of trachinoid, uranoscopoid, notothenioid, and stichaeoid fishes. Studies are presently being made on possible interrelationships between clusters within the 60 or more families of percoid fishes (suborder Percoidei). The placement and relationships of the atherinoid (sometimes called percesocine) fishes are still in dispute. The present classification follows that of Greenwood et al. in the removal of Atherinidae from perciform fishes and in the removal of the ophidioid and zoarcid fishes. Support for retaining the Atherinidae in order Perciformes and for other differences in the order Perciformes has been given by an American ichthyologist, W.A. Gosline, in a series of papers published between 1962 and 1971. Questions of relationships between carangid, rachycentrid, echeneid, and scombroid fishes are still unsettled. Many large and exciting problems thus remain. Warren Curtis Freihofer