摘要：

Studies with ultrasonic tracking techniques and oceanographic sampling demonstrated that oceanographic conditions play an important role in the local concentrations and movements of albacore, Thunnus alalunga. in US. coastal waters. Albacore show a tendency to congregate in the vicinity of coastal upwelling fronts, presumably to feed. They move away from the immediate area when upwelling ceases and the upwelling front is no longer present at the surface. The movements of albacore also appear to be related to the distribution of sea surface temperature, with fish spending little time in water with surface temperatures cooler than 15.O"C. The average swimming speed for three fish tracked between 27.8 and 50 h was 1.6 knots (82.4 cm/s) with each fish exhibiting slightly faster swimming speeds during hours of daylight than during hours of darkness. The albacore, Thunnus alalunga (Bonnaterre), is widely distributed in the Pacific Ocean. The single subpopulation which is found in the North Pacific (Otsu 1960) supports important surface commer- cial fisheries in coastal waters off North America and Japan and subsurface fisheries in the central temperate Pacific. The species is also highly prized by US. recreational fishermen. Passive tagging methods have been used to study large-scale mi- gratory patterns of albacore in the North Pacific (Ganssle and Clemens 1953; Otsu 1960; Clemens 1961, 1963; Otsu and Uchida 1963; Laurs and Nishimoto4); however, information on small-scale movements is scant. In order to examine the small-scale movements of schools of albacore and evaluate the effects that oceanographic conditions may have on the local concentrations and movements of albacore in coastal waters off the United States, studies were conducted with ultrasonic tracking techniques and oceanographic sampling. Tracking the movements of animals to which ultrasonic transmitters have been attached is a technique that has been developed over the past two decades. This valuable technique has gained

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