An interesting aspect of these graphs is the noticeable differ- 

 ence in the positions of the dominant modes between adjacent years. 

 For example, the year 1952 (fig. 9) has a dominant mode at about 150 

 pounds in January that progresses to 185 pounds by December and a 

 secondary mode beginning at about 95 pounds in January that moves to 

 about 120 pounds in December. The year 1953 (fig. 10), on the other 

 hand, has but a single dominant mode, which is apparent for nearly 

 all months of the year. This can be seen at about 115 pounds in Janu- 

 ary and progresses to about 165 pounds in December. In comparing 

 the same month there is no evidence of similarly situated dominant 

 nraodes in the 1952 and 1953 data. This lack of agreement between the 

 dominant modal size groups of adjacent years holds true for all years 

 examined. 



There are, however, strong resemblances between the distri- 

 butions of sizes in alternate years. To illustrate the differences be- 

 tween adjacent years and the resemblances of alternate years, Decem- 

 ber samples of all available years (1947-1954) have been plotted as 

 percentage weight frequencies in figure 12. It is self-evident that 

 there is a persistent difference between but a similarity within the 

 series of odd- and even-numbered years. This points to a cycle of 

 dominant weight groups with a period of about 2 years. 



Dominant nnodes are not found in exactly the same position 

 each second year, but increase in size (fig. 12). Looking at odd- 

 numbered years first, in December 1947 the dominant mode was 

 centered at 140 pounds, but by December 1953 it had progressed to 

 l65 pounds. For the even-numbered years there are two dominant 

 modal groups that act similarly. A small dominant mode at 105 

 pounds in the December 1948 sample can be traced through each even- 

 numbered year until it reaches 150 pounds in December 1954. A 

 larger dominant mode that occurred at 155 pounds in 1948 can be seen 

 progressing through all the December samples of even-numbered 

 years, reaching 205 pounds in the 1954 sample. 



An average of less than 24 months elapses between the appear-- 

 ance of dominant size groups in the Hawaiian fishery. This is indi- 

 cated by the "growth lines" fitted by eye (fig. 13) to the modes from 

 the monthly distribution (figs. 5-11, table 2), and by the increasing 

 size of apparently homologous modes as they reappear in the fishery 

 every 2 years (fig. 12). If these modes represent year classes, this 

 could mean that the peak of spawning or spawning survival takes place 

 a little later every second year, which seems unlikely. It is more to 

 be expected that spawning recurs at about the same time each year and 



16 



