men off the coast of North America, (2) the 

 winter longline fishery by Japanese in the west- 

 ern North Pacific Ocean, and (3) the spring 

 pole-and-line fishery by Japanese in the west- 

 ern North Pacific Ocean. We shall call these 

 the North American, the longline, and the pole- 

 and-line fisheries, respectively. Figure 1 

 shows the location of each of these fisheries, 

 and figure 2 shows the relative importance of 

 each in terms of landings. Much of the litera- 

 ture in English can be found in the description 

 of the North American fishery in Clemens and 

 Craig (1965), of the longline fishery in Suda 

 (1963b), and of the pole-and-line fishery in Suda 

 (1963b) and in Van Campen (1960). The migra- 

 tions of the albacore among these fisheries 

 have been described, only recently, by Clemens 

 (1961), Otsu and Uchida (1963). and Yoshida and 

 Otsu (1963). 



The importance of the albacore to both Japa- 

 nese and American fishing interests suggested 

 the institution of a cooperative program be- 

 tween Japanese and United States researchers 

 to study this fish in the Pacific Ocean. An ex- 

 change of data on the longline fishery for alba- 

 core between the Nankai Regional Fisheries 

 Research Laboratory (now a part of the Far 

 Seas Fisheries Research Laboratory at Shimizu) 

 and the Bureau of Commercial Fisheries was 

 one of the first steps in this cooperative pro- 

 gram. The data that we obtained consisted 

 primarily of nominal longline effort (in number 

 of hooks fished) and catch in numbers of alba- 

 core. These data were arranged by month and 



1° quadrangles of ocean for the years 1949-61. 

 There were albacore catch-and-effort statistics 

 for about 50,000 one-degree squares and months. 

 Unfortunately, the catch statistics for species 

 other than the albacore were not included in the 

 data that were made available to us. 



After completing this study we compared our 

 results on CPUE (catch-per-unit-of-effort) with 

 unpublished Japanese data provided to us by 

 Akira Suda and found some disagreement owing 

 to Suda's using a slightly different data set. 

 The differences, however, do not appear to 

 affect materially any of our interpretations or 

 conclusions. 



The present paper, then, provides a summary 

 and discussion of these data as they relate to 

 the dynamics of the albacore in the North Pa- 

 cific Ocean. The paper is divided into three 

 sections. In the first, we describe the decline 

 in apparent abundance of the albacore in the 

 1950's; in the second, we provide spatial statis- 

 tics for the distribution of albacore in the long- 

 line fishery; and in the third, we provide evi- 

 dence that indicates that the predominant mi- 

 gratory route of the albacore is from the North 

 American to the pole-and-line to the longline 

 fishery. 



APPARENT ABUNDANCE 



Apparent abundance will be considered from 

 two points of view. First, the long-term trends 

 in CPUE will be considered. Second, the devia- 

 tions from these trends will be considered. 



Figure 1 . --Approx imate loca- 

 tion of the North American, 

 longline, and pole-and-line 

 albacore fisheries. 



