220
THE BIOLOQY OP EUPHAUSIIDS
M. norveqh
i
p . . . . .
100
20
5
Jy A S 0 D J F M A M J J
Jy AS 0 D J F M A M J J
195 I
1952
1951
1952
FIG. 76. Seasonal variations and concentrations of oil percentage, weight, vitamin A,
and astaxanthin in selected groups of Meganyctiphanes norvegica and Thysanoissa
raschii. 0-0, oil; 0- - - -0, weight; .--., vitamin A ; 0 - - - - 0 ,
astaxanthin. (After Fisher et al., 1954.)
16 months of a period of 18 months. Many of these graphs indicate that
these two substances fluctuate in a similar manner but, on one
occasion, the relative values of astaxanthin increased steadily over a
period of two or three months while those of vitamin A remained at
TABLE XVIII. OIL PERCENTAGE, AND VITAMIN A AND ASTAXANTHIN (pglg WET
WEIGHT) IN EUPHAUSIIDS (Fisher, Kon, and Thompson, 1955)
Average
weight
(mg)
No. of
Oil
Vitamin A Astaxanthin
(70)
(pgLgl9)
(P9lS)
specimens
Euphausia superba, early 1953
(weighted means)
Eyes
174
Bodies
174
Total
174
E . paci$ca, 25.v.53
Eyes
100
Bodies
100
Total
100
Eyes
40
Bodies
40
Total
40
Nemato.scelis discilia, 25.v.53
Stylocheiron elongatum, 2 x 5 2
Eyes
4
Bodies
4
Total
4
S . maximum, 25.v.53
Eyes
2
Bodies
2
Total
2
2.8
4.5
408
2.5
41 1
2.5
1
13
49
1 *9
50
2.2
2
5.2
35
3.3
37
3.4
2
2.3
30
0.8
32
0.9
7
14
46
8-4
53
9.0
205
1 1 5 5
0-4
8.8
1.4
16.5
203
683
0
7.7
4.3
22
72
314
1
10
4.3
23
72
1090
0
41
5.1
113
38
365
0
0
5.1
50