264 
PACIFIC SCIENCE, Vol XIV, July I960 
other in waters of the American fishery off the 
Pacific northwest. One was recaptured in June, 
1958, in the Japanese live-bait fishery, and the 
other, a month later in the American fishery. 
The suggestion is that the latter had also under- 
gone an extensive migration to the west before 
returning to the American fishery, although 
this movement may not have been as complete 
as the other. A similar suggestion is made by 
the recapture in the American fishery after 306 
days of an albacore tagged by the California 
Department of Fish and Game. One other al- 
bacore, tagged at the same time, had been re- 
captured a month earlier 145 miles east of 
Tokyo, Japan (Anonymous, 1957). An appre- 
ciable tagging program by the Japanese may 
show definitely whether or not there is a move- 
ment of fish from the Japanese live-bait fishery 
into the American fishery. 
However, judging by the sizes of fish gen- 
erally taken in the different fisheries, it is pos- 
sible that even extensive tagging by the Japanese 
would not confirm such a movement towards 
the east. The chances for American recovery of 
Japanese-tagged fish are not good unless the 
Japanese tag unusually small fish or unless 
unusually large fish move into the American 
fishery in large numbers. The sizes of fish com- 
monly taken in the respective fisheries are 
Fig. 9- Examples of albacore sizes taken by the ma- 
jor North Pacific fisheries. The Japanese size-frequen- 
cies were obtained from Nankai Regional Fisheries 
Research Laboratory (1951). The West Coast length 
frequency is based on unpublished data of the Oregon 
Fish Commission and are measurements made on alba- 
core landed in Oregon during the 1957 season. 
shown in Figure 9. The American West Coast 
fishery generally takes smaller albacore than 
either the Japanese live-bait fishery or their 
long-line fishery; the fish range in size from 
about 50 to 85 cm. with the predominant sizes 
around 65 cm. The bulk of the fish taken by 
the Japanese is larger than 70 cm. in length, 
and these sizes comprise only a very small part 
of the American landings. On the other hand, 
small albacore under 70 cm. may be present in 
larger numbers in the Japanese live-bait fishery 
than indicated in Figure 9- Suda (1955) states 
that such small fish constitute a significant por- 
tion of the landings during certain years. The 
chances for recovery would seemingly be im- 
proved if tagging is concentrated on such small 
fish. 
Although there appears to be little chance for 
fish tagged in the western Pacific to be recovered 
in the American fishery, a large-scale tagging 
program by the Japanese stands to serve an 
equally important purpose, that of elucidating 
the relationship between the albacore of the 
temperate and tropical Pacific Ocean. There is 
at present no direct knowledge concerning the 
movements of the larger albacore. The larger 
fish of the temperate North Pacific appear to 
move south into tropical and subtropical waters, 
perhaps to form the reproductive segment of 
the population. If there is such a southward 
migration of the larger fish, this may be shown 
someday by the recovery of a tagged fish. With 
Japanese vessels exploiting wide areas in the 
tropical Pacific, chances for recovery of fish 
tagged in the north should be favorable. 
With respect to the growth curve obtained in 
this study, there are certain implications which 
merit brief consideration. If the Gompertz curve 
(Fig. 7) is a true representation of albacore 
growth, then the following points may be made: 
(a) the albacore is a relatively slow-growing 
tuna; (b) this species has a relatively long life 
span. Furthermore, as mentioned, it is believed 
that an albacore attains sexual maturity at a 
length of about 90 cm. If this is so, then it re- 
quires between 7 and 8 years for an albacore to 
become sexually mature. This is a significant 
portion of the life span. Since albacore enter 
the fisheries in substantial numbers at around 
50 cm. in length (Fig. 9), a year-class is thus 
