The spearfishes and sailfishes, like the swordfish, have a sword formed by the prolongation of the snout and upper jaw. But their sword is rounded toward the tip, not flattened, and narrower than that of the swordfish. Their bodies, too, are closely clothed with narrow lanceolate scales, pointing rearward in general and embedded in the skin, either wholly or with their sharp tips projecting slightly (fig. 188), and their first dorsal fin is much longer, occupying the greater part of the back behind the nape, and it can be depressed into a groove along the back. They fall in two groups, sailfishes with very large, sail-like dorsal fin, and spearfishes or marlins with lower dorsal.
The sailfish (Istiophorus americanus Cuvier and Valenciennes 1831), so common in the warmer parts of the Atlantic, is included in the following Key because it has been taken at Woods Hole on several occasions, though not yet recorded from the Gulf of Maine. It is readily recognizable by the fact that the first dorsal fin is much higher than that of the marlins while the ventral fins of the sailfish are 2- or 3-rayed instead of being reduced to a single spine, as in the marlins. The two dorsal fins of the sailfish have usually been described as connected even in the adult. This, [page 358] in fact, is given as the chief distinction between it and the marlins by Goode by Jordan and Evermann, and by Boulenger. But there is actually a considerable gap between the two fins in large specimens as Bean remarks and as appears on Goode's own illustrations of a sailfish taken at Newport, and of a skeleton.
Two species of marlins, the blue and the white are known off the middle and north Atlantic Coasts of the United States. But it is not yet clear whether the enormous marlins, with violet cross-stripes on the sides, that are caught off the North Coast of Cuba are simply very large blue marlin, a separate subspecies, or even a species. And the marlins of more southern waters still await critical study.
|KEY TO SPEARFISHES OR MARLINS, AND SAILFISHES|
|Middle Atlantic and North Atlantic Coast of United States.|
|1.||First dorsal fin much higher than the body is deep and sail-like; ventrals of 3 rays each||—||Sailfish, p. 357|
|The first dorsal fin is not higher than the body is deep; ventrals reduced to one spine each||2|
|2.||Apex of first dorsal fin and tips of pectorals pointed||—||Blue marlin, p. 358|
|Apex of first dorsal and tips of pectorals rounded||—||White marlin, p. 360|
 Rept. U. S. Comm. Fish., 1880, p. 296.
 Bull. 47, U. S. Nat. Mus., Pt. 1, 1896, p. 890.
 Cambridge Natural History, vol. 7, 1904, p. 680.
 Bull. New York State Mus., 60, Zool. 9, 1903, p. 404.
 Hemmingway (in Vesey-Fitzgerald and Lamonte, Game Fishes of the World, 1949, p. 158) reports these striped marlins weighing up to 1,250 pounds off northern Cuba.