35 Behavior 351 Migrations and local movements Sailfish perform long-range migrations of thousands of miles as well as fairly extensive short-term movements most likely based on local environmental conditions. Mather et al. (1974) reported on the results of 18 yr of billfish tagging under the Woods Hole Oceanographic Institution Cooperative Gamefish Tagging Program. Over 12,000 sailfish were tagged and 95 recoveries were recorded (Table 7). The longest distance between release and recovery was from off Cape Hatteras, N. C, to just north of Surinam, a distance of over 1,853 km (Fig. 5). The longest time at large was over 4 yr. Voss (1953) believed that there is a population of sailfish present off Florida all year long, but in summer with the extension of warm water northward there is a movement of sailfish northward along the inside edge of the Gulf Stream. With the arrival of the winter northerlies these fish are driven southward to regroup off the coast of Florida. Squire (1974) reported on the results of a billfish tagging program in the eastern Pacific from 1954 through 1971. Over 4,700 sailfish were tagged; only 8 were recovered. Most recaptures were near the tagging locality and the longest period at large was 15 mo. Nakamura et al. (1968) stated that sailfish in the western Pacific migrate from New Guinea, the Solomon Islands, and the Philippines along the Japanese Current to Japan and the Pacific coast of Mexico. In autumn sailfish enter the warm Tsushima Current and move into coastal waters where they are sometimes captured in traps. In the East China Sea, Koto et al. (1959) reported that sailfish migrate northward in summer and return southward in autumn where they overwinter in the southernmost area. They also reported that fish under 160 cm long move into the area between May and July while fish over 160 cm move southward out of the area, probably for spawning. In the Indian Ocean, Williams (1970) and Merrett (1971) discussed the movements of sailfish off the coast of East Africa. Williams believed that there are two overlapping migratory patterns, one a localized onshore-offshore migration with a superimposed migration from the north and northeast with the intrusion of the Somali Current. Merrett believed that the onshore migration was a postspawning, feeding migration. 352 Schooling Sailfish occasionally form schools or groups of from 3 to 25 or 30 individuals. More often, however, concentrations of sailfish occur in loose aggregations over a broad area. Large numbers of sailfish occur off the southeast coast of Florida during the winter months. Voss (1953) reported that in early morning sailfish off the Florida coast were scattered, but by 0900 schools of up to 30 fish began to form and feed on concentrations of small forage fish. Furukawa (1961) presented a method of calculating the size of an average school or aggregation using the Table 7— Releases for Atlantic sailfish, Istiophorus albicans, in the western North Atlantic by years, and returns from these by months at liberty (from Mather et al. 1974). Releases Months at liberty 0-09 1-19 2-59 6-119 12-179 18-239 24-359 36-479 Totals Total 12,005 22 11 24 24 5 6 10 9 6 9 17 13 10 5 1 1 95 110