292 
BULLETIN OF THE BUREAU OF FISHERIES 
33.9 meters 3.3°. The wind, temperature, and direction of the current at this time 
were favorable for profound changes in the relation of waters of different salinities. 
There was a moderate breeze blowing from north-northeast at about 15 miles per 
hour, the sea was rolling, and there was an outgoing current moving slowly almost 
without exception from surface to bottom throughout 24 hours of observation. 
These conditions, together with a rapid fall in air temperature two days previous to 
the time when the water samples were collected and a continued low air temperature 
of about — 4° C., were probably the cause of the almost homothermous and homo- 
haline relations. 
SALINITY OF WATER DURING SPRING 
The salinity data for 1916 show that the deep-water salinity values found in the 
bay were considerably less, with very few and unimportant exceptions, during the 
March cruise than during the January cruise. The same was true for 1920 and 1922. 
This relation did not hold in the lower half of the bay between the January and March- 
April cruises of 1921. The exceptional mildness of the month of January, resulting 
in a flood of fresh water, probably accounts for the difference. The evidence on the 
whole from the four years indicates, nevertheless, that in the spring there is a decrease 
in the salinity of Chesapeake Bay. Such a condition would be expected, if for no 
other reason than that in the spring months the maximum discharge occurs in the 
larger rivers which empty into Chesapeake Bay. (Table 2.) 
Table 2. — Temperatures and salinities at surface, 20 meters, and 30 meters, during March, for various 
years and areas 
Areas 
March, 1916 
March-April, 1921 
March, 1922 
Tem- 
pera- 
ture, 
° 0 ., 
surface 
Sa- 
linity, 
surface 
Temperature, 0 C. 
Salinity 
Temperature, 0 C. 
Salinity 
Surface 
20 me- 
ters 
30 me- 
ters 
Surface 
20 me- 
ters 
30 me- 
ters 
Surface 
20 me- 
ters 
30 me- 
ters 
Surface 
20 me- 
ters 
30 me- 
ters 
G 
3. 7 
3. 1 
2.3 
1.8 
1. 6 
1.7 
1. 1 
1. 2 
1.4 
28. 15 
20. 14 
15. 17 
15. 25 
14. 94 
14.61 
12. 92 
10. 55 
9. 25 
12. 1 
12. 1 
10.9 
11.4 
10. 2 
10.8 
10.5 
12. 4 
12.7 
27. 74 
21. 56 
14. 30 
14. 26 
13. 94 
10. 87 
7. 43 
5. 26 
3. 61 
8.9 
7.3 
8. 1 
7.2 
7.7 
7.3 
8. 2 
9. 2 
9.0 
18. 36 
19. 33 
11.62 
12. 21 
A 
11.3 
11.4 
24. 62 
28. 23 
7.0 
S:? 
4.9 
6.7 
6.5 
5.6 
5.2 
23.91 
17. 89 
16. 95 
25. 10 
18. 20 
17. 12 
.7 
I, 
R 
10.7 
14. 20 
s 
11.89 
9. 84 
5. 65 
5. 22 
x 
9.9 
8.4 
10. 38 
13. 53 
4.5 
5. 2 
15. 26 
15. 79 
Y 
u 
A discontinuity in the vertical distribution of salinity is usual along the deep- 
water channel for the spring cruises, although the salinity is as a rule lower than at 
other seasons of the year. At times, however, as in the early part of March, 1920, 
when one of our cruises was made, the vertical distribution of salinity approached 
homohalinity at several areas in the northern part of the bay. Only during the winter 
(fig. 10) and spring cruises has this condition been observed. On the morning of 
March 6 we began to take samples at area U and continued their collection every 
hour and a half until 11.45 p. m. Throughout the day the salinities were unusually 
similar from surface to bottom — for example, at 1.15 p. m., surface 10.05, 3 meters 
10.11, 6 meters 10.17, and bottom (9 meters) 10.71. At station 8748, between areas 
R and L, a similar condition was found: Surface 16.11, 10 meters 16.14, 20 meters 
16.14, 30 meters 16.16, 35 meters 16.22. The conditions were favorable for such 
distribution of salinity. At area U the sea was rough, a 15-mile wind blew from the 
northwest, ice floes were in the bay, there was no dominating flood current, and the 
