38 
PACIFIC SCIENCE, Vol. IX, January, 1955 
TABLE 3 
Number (in Parentheses) and Percentage of Normal, Damaged, and Agglutinated Eggs by Months 
MONTH AND YEAR 
NORMAL 
DAMAGED 
AGGLUTINATED 
9/50 
(129) 43.4 
(49) 16.5 
(119) 40.1 
10/50 
(102) 43.6 
(66) 28.2 
(66) 28.2 
11/50 
(32) 30.2 
(29) 27.4 
(45) 42.4 
12/50 
(71) 14.1 
(138) 27.4 
(295) 58.5 
1/51 
(29) 6.1 
(242) 51.1 
(203) 42.8 
2/51 
(66) 13.7 
(222) 46.3 
(192) 40.0 
3/51 
(4) 2.8 
(109) 76.2 
(30) 21.0 
4/51 
(124) 43.2 
(143) 49.8 
(20) 7.0 
5/51 
(784) 23.9 
(1,386) 42.3 
(1,110) 33.8 
6/51 
(1,830) 41.6 
(1,555) 35.3 
(1,018) 23.1 
7/51 
(6,110) 47.7 
(4,648) 36.3 
(2,048) 16.0 
8/51 
(3,991) 64.9 
(1,089) 17.7 
(1,072) 17.4 
9/51 
(528) 43.1 
(323) 26.4 
(373) 30.5 
10/51 
(292) 77.4 
(32) 8.5 
(53) 14.1 
11/51 
(19) 61.2 
(7) 22.7 
(5) 16.1 
12/51 
(5) 33.3 
(4) 26.7 
(6) 40.0 
1/52 
(2) 66.7 
(0) 0.0 
(1) 33.3 
2/52 
(0) 0.0 
(0) 0.0 
(2)100.0 
3/52 
(1) 5.6 
(6) 27.7 
(12) 66.7 
4/52 
(47) 24.5 
(143) 74.5 
(2) 1.0 
5/52 
(3) 6.2 
(23) 48.0 
(22) 45.8 
6/52 
(23) 12.0 
(81) 42.2 
(88) 45.8 
7/52 
(521) 37.3 
(450) 32.3 
(424) 30.4 
8/52 
(1,344) 64.7 
(446) 21.5 
(286) 13.8 
All 
(16,057) 46.2 
(11,191) 32.2 
(7,492) 21.6 
from data discussed by Tester (1951: 338- 
340). The differences between investigations 
in the last two categories may be due, in part 
at least, to a change in interpretation of bor- 
derline cases of the "damaged” and "agglu- 
tinated” condition, although an effort was 
made to acquaint each of the several plankton 
sorters with the same objective criteria. The 
indications are that the number of agglu- 
tinated eggs averaged higher in 1950-53 than 
in 1949-50, but perhaps in a smaller ratio 
than that shown by the data (21.6 to 4.5, or 
5 to 1). In any case, it is believed that the 
interpretation of the differences between 
"damaged” and "agglutinated” was reason- 
ably consistent within the recent investigation. 
The monthly percentages listed in Table 3 
vary widely, but show a tendency for normal 
eggs to be relatively more abundant than ag- 
glutinated eggs during the summer and for 
agglutinated eggs to be relatively more abund- 
ant than normal eggs during the winter. The 
seasonal trend is illustrated in Figure 4. Be- 
cause of the varying inherent accuracies of the 
percentages it is difficult to establish the 
statistical significance of the seasonal change. 
However, it may be shown readily that the 
differences in monthly ratios of normal to 
total and of agglutinated to total are unlikely 
due to chance. For example, a test of inde- 
pendence applied to the ratios of agglutinated 
to total yielded an extremely high Chi-square 
(3,067 for 21 degrees of freedom) which was 
highly significant (P < 0.001). 
