Albacore — Otsu 
259 
Fig. 2. Numbers and locations of POFI tag releases, January, 1954- August, 1957. (California type-G tag 
was used on 1,090, and the POFI dart tag on 111 albacore.) 
GROWTH SHOWN BY THE TAGGED ALBACORE 
Of 15 recoveries to date, 11 were accompanied 
by size data at the time of recovery (Table 2). 
The estimated annual growth of these fish was 
extremely variable, ranging from 3.8 to 28.7 
cm. per year. 
Although it is realized that the available data 
are inadequate for any conclusive growth study, 
a preliminary analysis was made in order to 
present some approximation of the albacore 
growth rate. Following the method of growth 
curve transformation described by Waif or d 
( 1946), the length of fish at the time of release 
(age N) was plotted against the length after 
one year (age N + 1), the latter representing 
the length at release plus the estimated value of 
one year’s growth ( Fig. 5 ) . There is a suggestion 
of linearity in the plots, with the exception of 
one (No. 2, Table 2). The growth reported for 
this fish is obviously out of proportion to the 
others. When the Japanese transmit data perti- 
nent to a tag recovery they usually specify the 
method of measurement used. This was not done 
in this particular instance; for this reason and 
because the reported length seems excessive, 
this fish is dropped from further consideration. 
The remaining 12 points (including two from 
published California data) fall about the re- 
gression line Y = 26.29 + .77867X obtained 
by the least squares method, where Y is the 
length at N + 1, and X the length at N. 
Also shown in Figure 5 is the line of no 
growth (Ln = Ljv + i) drawn in with a 45° 
slope through the origin. The point of inter- 
section between the regression line and the line 
of no growth is described by Walford as the 
upper asymptote of the growth curve, which in 
this case falls at approximately 118 cm. The 
118-cm. asymptote of maximum growth for 
the sample data of this paper is slightly less 
than that which would be expected for albacore 
populations in general; measurements of com- 
mercial landings indicate the population asymp- 
tote to be about 124 cm. (Suda, 1954; Otsu 
and Uchida, 1959^). 
The growth curve (Fig. 6) was derived from 
Figure 5. This method does not enable us to 
obtain that portion of the growth curve falling 
below the point of inflection, and since the 
smallest fish for which there are data is a 60- 
cm. fish, the extrapolation toward the smaller 
sizes is dubious. 
In an attempt to describe the complete growth 
curve, particularly that portion falling below 
the point of inflection, for which Walford’s 
method does not apply, the data were fitted to a 
Gompertz equation, y = ab , where y is the 
length in centimeters and x the age in years. A 
