494. Chemical Study of Food Fishes — 
TABLE VII. 
Analyses of Weakfish from the Same School. (Caught November 11, 1914.) — 
Composite Samples of Three Fish Each. | 
No. of sample. Solids. Fat. Ash. Total nitrogen. 
per cent per cent per cent per cent 
1 22.88 1.35 1.16 3.13 
2 23.35 2.47 1.10 3.13 
3 25.51 4.88 te Fe) 3.09 
4 28.22 8.03 1312 3.19 
A study of Table IV shows that weakfish may contain more 
fat in the spring than in the early autumn. We know but little 
of the habits of the weakfish. However, during September we 
find them full of feed, although the fat content of the fish is ex- 
tremely low; for example, 0.52 per cent. It may be deduced 
from this figure that the fish have recently entered upon a feed- 
ing period, which assumption is further confirmed by the fact 
that later in the year—about the middle of November—as much 
as 8.03 per cent of fat was found (Table VII). 
The literature fails to record the analysis of the flesh of the 
shad before and after its spawning migration. Accordingly, a 
study of this fish was made, covering a period of about 2 months, 
during which time the fish had appeared at the mouth of the 
rivers and had ascended them to fresh water. ‘The later analyses 
were made at the close of the shad season. The results are shown 
in Table IV. The most striking differences are those in the fat, 
this constituent decreasing from 14.48 per cent before spawning 
in April to 2.95 per cent after spawning in June. ‘There is like- 
wise a decrease in the water-soluble and coagulable nitrogen, an 
increase in the specific gravity, iodine number, and acid value 
of the fats, and a lowering of their saponification numbers. 
The shad, like the salmon, does not feed from the time it en- 
ters upon spawning migration until it returns to the feeding 
grounds. Some of the fat is consumed in the tissues to furnish the 
energy necessary for ascending the rivers, and the remainder is 
probably transferred to the roe and milt. It would be profit- 
‘able to extend this investigation to a similar study of the’ hanes 
in other fish at spawning time. ' 
