232 
BULLETIN OF THE BUREAU OF FISHERIES 
is not so heavy and the fish are very wild, whereas on dark nights they lie very still and have no 
fear of a noise. 
Temperature records of the water were kept from March 6 to April 13, both in- 
clusive, both at noon and midnight, as follows: 
Date 
Noon, ° F. 
Midnight, 
° F. 
Date 
Noon, ° F. 
Midnight, 
° F. 
Mar. 6 __ 
37 
35 
Mar. 25 
43 
42 
Mar. 7_ 
38 
36 
Mar. 26 
46 
44 
40 
38 
Mar. 27 
47 
44 
Mar. 9 
39 
37 
Mar. 28 - 
43 
37 
Mar. 10 
40 
37 
Mar. 29 
30 
(i) 
38 
36 
Mar. 30 
31 
(2) 
40 
37 
Apr. 4 
39 
37 
31 
Apr. 5 
39 
39 
Mar. 14 
38 
30 
Apr. 6 
38 
38 
30 
29 
Apr. 7 
41 
44 
Mar. 16 
30 
30 
Apr. 8 
48 
49 
29 
(l) 
48 
46 
40 
40 
42 
44 
Mar. 22 
40 
39 
Apr. 11 
48 
48 
Mar. 23 . 
37 
60 
50 
Mar. 24 
47 
42 
51 
50 
1 lee on ponds and rivers. ! Ice on falls. 
The report for 1920 (p. 71) says: 
Mild weather prevailed the third week of March, and on the 25th the fish made their first 
appearence at the falls in the Weir River, Hingham. * * * . Heavy rains began to fall and 
the water in the river rose to the freshet mark. The deep, swift-flowing current of water was more 
than the spawn-loaded fish could navigate, and they appeared content to remain far below the falls, 
where they deposited their spawn upon the river bottom. * * * . 
As soon as the water receded to its normal flow, making it possible for the fish to reach the 
falls with ease, the weather broke, and cold and stormy weather prevailed. The mild weather of 
April was of brief duration and the water temperatures fluctuated greatly. The spawn in the fish 
develops only in warm water, and the sudden changes in water temperatures retarded this develop, 
ment to such an extent that the depositing of spawn was not completed until the middle of May, 
making the season one of the longest on record. 
The report for 1921 (p. 75) says: 
Following a generally open winter, spring came early, and the spawn-loaded fish made their 
first appearance at the Weir River, Hingham, on the night of March 8, nearly three weeks ahead 
of the normal year. Both water and weather offered the most favorable conditions possible, and 
by March 10 an abundance of smelt was to be found in all the streams. A very large run was 
observed in all the South Shore streams for two weeks, until about March 22, when the numbers 
began to fall off, notwithstanding favorable conditions, indicating the first run had completed 
spawning. The new run, from April 13 to the freshet of April 29 to May 1, was reasonably steady. 
To the best of our observations the 1921 run of smelt was the greatest in a number of years, 
being about 25 per cent greater than that of 1918, which was a record year. With the water at 
normal height throughout the season of 1921 there was no such destruction of spawn as occurs 
when, during a freshet, it is deposited on the high shoals, only to be left high and dry with the 
recession of the waters. The natural hatch was unusually heavy. * * * . 
It appears that a temperature of at least 45° F. is necessary for the opening of the spawning 
season. 
The report contains a chart showing the comparative run of smelt in the Weir 
River, Hingham, during 1918, 1920, and 1921, as well as the temperature of the 
water in 1921. Concerning this chart the report says that the intimate connection 
