294 
BULLETIN OF THE BUREAU OF FISHERIES 
Table 4. — Temperatures and salinities at surface, 20 meters, and 30 meters, during September , October, 
and December, for various years and areas 
Areas 
September, 1916 
October, 1920 
December, 1920 
Tem- 
pera- 
ture 
°C., sur- 
face 
Salin- 
ity, sur- 
face 
Temperature, ° C. 
Salinity 
Temperature, ° C. 
Salinity 
Sur- 
face 
20 
meters 
30 
meters 
Sur- 
face 
20 
meters 
30 
meters 
Sur- 
face 
20 
meters 
30 
meters 
Sur- 
face 
20 
meters 
30 
meters 
G __ 
20.4 
20.4 
20. 0 
19.7 
20.28 
21. 99 
14.87 
15.89 
10.5 
10.3 
9. 5 
8.7 
8.6 
7.8 
7.9 
7.4 
7.0 
11.3 
10.2 
9.7 
10. 1 
9.5 
25. 20 
30. 22 
A 
23.4 
24. 1 
23. 59 
14.54 
20. 0 
19. 3 
19.5 
19.4 
. 19. 5 
19.3 
26. 18 
22. 80 
20.20 
27. 02 
10.2 
10.0 
10. 1 
9.9 
J 
L 
22. 24 
15. 14 
14. 93 
14.69 
12. 42 
10. 64 
9. 13 
19.51 
18. 35 
20. 10 
19.68 
R 
S . 
23.9 
23.9 
24.4 
12. 05 
11. 09 
9. 56 
20.2 
19.4 
19.2 
19.8 
13. 72 
13. 70 
X 
16. 00 
8.8 
12.84 
Y 
U 
9. 25 
SEASONAL SURFACE SALINITIES DURING 1916 
I have stated that the salinity values obtained during the different seasons 
indicate that in the spring the salintiy in Chesapeake Bay decreases markedly, that 
in the summer it begins to increase again, reaching its highest degree ordinarily in 
the fall and winter. Inspection of the surface salinity values obtained at areas 
G, F, D, C, B, A, H, J, I, M, X, and Z for the cruises of January, March, April, June, 
July, and September, 1916, tends to support this contention so far as surface water is 
concerned (Table 5), although in these data, as well as those which have been given 
above, the water samples were not taken simultaneously at the various areas, so that 
they were not collected necessarily at the same stage of the tide. However, the rather 
close uniformity in the seasonal fluctuation of the salinity values for each area indi- 
cates strongly that they show, in a comparative way, the salinity conditions in the 
bay. 
Table 5. — Surface salinities during 1916 
Areas 
Janu- 
ary 
March 
April 
June 
July 
Sep- 
tember 
Areas 
Janu- 
ary 
March 
April 
June 
July 
Sep- 
tember 
a 
23. 40 
28. 15 
21.92 
22.92 
24. 90 
H 
18. 53 
17.30 
13. 21 
14. 33 
15.99 
16. 31 
F 
30. 48 
25. 23 
18. 89 
25. 14 
26. 69 
27. 54 
J 
15. 14 
15. 17 
10. 80 
12. 97 
16.31 
14.54 
r> 
19 85 
18. 46 
17. 18 
17. 30 
21. 46 
I__ 
13. 37 
15. 79 
11. 55 
13. 24 
11. 78 
15. 21 
C 
19. 98 
18.91 
15. 84 
17. 81 
21.62 
21.55 
M 
13.73 
13. 59 
11. 09 
11.76 
9.99 
13. 26 
R 
21. 47 
18. 93 
16. 28 
21. 17 
21.62 
21.65 
X 
11. 13 
12.92 
5.88 
8. 30 
5.41 
11.09 
A 
22.74 
20. 14 
18.46 
22. 11 
22.54 
23. 59 
z 
9. 29 
10. 01 
3. 35 
3. 10 
4.25 
10. 16 
SEASONAL SURFACE AND 30-METER SALINITIES FOR AREA L DURING 24 HOURS 
As further evidence supporting the belief that the salinity decreases in the spring 
and rises again to a maximum in the latter part of the year we have the data from 
water samples collected usually at 1%-hour intervals through 24 hours. Such data 
bring out the tidal fluctuation in salinity during that period as well as the changes 
from cruise to cruise (1920). 
The 24-hour observations were not begun at area L until the July cruise, but the 
single surface salinity determinations for area L in March and May were 15.87 and 
7.30, respectively. The data for the July and October cruises (1920) show an increase 
over those of the May cruise, while on the cruise during the unseasonably mild month 
of January, 1921, the salinity values decreased again. (Table 6.) 
