NATURAL HISTORY OF THE QUINN AT SALMON. 
99 
Table showing effect of salt water on alevins and fry. 
Experiment 13. 
Experiment 15. 
Experiment 16. 
experi- 
Percent- 
Percent- 
Percent- 
Percent- 
Percent- 
Percent- 
ment. 
Age. 
age sea 
age 
Age. 
age sea 
age 
Age. 
age sea 
age 
water. 
dead. 
water. 
dead. 
water. 
dead. 
1 
26 
10 
0 
33 
0 
0 
33 
0 
0 
2 
27 
15 
0 
34 
10 
2 
34 
5 
1 
3 
28 
25 
1 
35 
35 
0 
35 
15 
5 
4 
29 
35 
1 
36 
40 
3 
36 
20 
5 
5 
30 
50 
7 
37 
50 
5 
37 
25 
5 
6 
31 
65 
84 
38 
55 
7 
38 
30 
1 
7 
32 
75 
100 
39 
60 
7 
39 
35 
2 
8 
40 
65 
34 
40 
40 
t 
9 
41 
65 
58 
41 
45 
8 
10 
42 
70 
83 
42 
50 
2 
n 
43 
80 
66 
43 
52 
6 
12 
44 
90 
100 
44 
70 
10 
13 
45 
70 
20 
14 
46 
80 
41 
15 
47 
65 
23 
16 
48 
60 
2 
17 
49 
60 
8 
18 
50 
60 
7 
19 
51 
65 
0 
20 
52 
85 
0 
21 
53 
70 
0 
22 
54 
65 
0 
33 
55 
93 
2 
34 
56 
50 
0 
25 
57 
93 
0 
26 
58 
93 
0 
27 
59 
95 
8 
28 
60 
95 
0 
29 
61 
Discontinued. 
Experiment 1 was made to cheek the others, showing that the loss was not the 
result of being confined in battery jars. 
Experiment 2 shows that 25 per cent sea water lias but little deleterious effect 
upon alevins over 5 days old. 
Experiments 3 to 7 show that alevins of 6 to 10 days of age can not live in sea 
water of 50 per cent or over, either when put directly from fresh water into the 
mixture or when the density is gradually raised. 
Experiments 8 to 11 show that alevins 12 days old can live longer in 50 and 75 
per cent sea water than those only 6 days old. Some of the 12-day alevins lived 
7 days in 50 per cent sea water, while the 6-clay ones lived but 3 days. The older 
alevins lived one day longer in 75 per cent, but died the first day in pure sea water, 
as did the 6-day individuals. 
Experiment 12 shows that when 19 days old they live longer yet in 50 per cent. 
Two lived 2 days in 75 per cent after having been in 50 per cent for 9 days. The 
one that lived till the twelfth day was a week older. 
Experiment 13 shows that a gradual rise from a density of 10 per cent sea water 
when 26 days old to 75 per cent when 32 days old was fatal. In a similar way a 
gradual rise from fresh water when 33 days old to a density of 90 per cent when 44 
days old was fatal, as is shown in experiment 15. 
Experiment 16 indicates that alevius 50 to 60 days old can bear a high density 
of sea water, but that they can withstand it better if the density, instead of increas- 
ing regularly, alternates between high and low. It does not show the exact age at 
which the fry can live in sea water, and it is doubtful whether this can be determined 
accurately in aquaria. Whether it can or not, the time was not at my disposal to 
carry the observations further. 
As a whole, the experiments show three important points. First, the fry can 
not live in sea water until several Aveeks after the yolk-sac is absorbed; second, when 
