DIVING PATTERNS OF AMA DIVERS OF HEGURA ISLAND, JAPAN

Daily diving patterns, especially depth-time profiles, were continuous ly recorded during the entire work shift in four cachido and four funa do divers of Hegura Island, Japan. All Hegura divers (cachido and funa do alike) were female and habitually wore wet suits. Cachidos dive fre e and unassisted from a boat or float, whereas funado divers are assis ted by weighted descent and during the ascent by being pulled by a par tner into a boat on the water surface. Both funado and cachido divers spent 250-280 min/day on the sea at their diving locations; the actual diving time was 100-120 min. The divers made 90-120 dives/day to a de pth of 13-22 m, each dive lasting similar to 60 s, considerably longer and deeper than those observed and recorded previously in ama divers in the Chiba and Miura regions. These dive profiles are similar to tho se reported by Paulev in which he observed apparent signs of decompres sion sickness when the subject dived to a depth of 15-20 m 100 times i n 5 h. The average bottom time for each dive of Hegura funados was 23. 6 s which is similar to 10 s longer than that of Korean female ama. Th e rate of ascent in the funado divers was 1.5 m/s, which is nearly twi ce that of the cachido divers (0.8 m/s). The dive frequency of Hegura funados (109 dives/day) was greater than the Chiba male funados (23 di ves/day). Accordingly, cumulative bottom time of Hegura funado was 48 min/day, whereas that of Chiba funado was 17 min/day. This markedly di fferent diving pattern between Hegura and Chiba divers may be because Chiba divers do not wear wet suits and are therefore considerably more exposed to the cold. Although the depth and number of dives per day m ade decompression sickness a possibility, it did not occur in Hegura a ma.