NATURAL HISTORY OF THE QUINNAT SALMON. 
97 
Movements in estuary and bay . — Much seining was done both years at Olema 
in trying to learn something of the movements of young salmon in brackish water. 
None was found in 1898. A few were caught near the mouth of Paper-mill Creek in 
1897, and one was taken 2 or 3 miles from the mouth of the creek, across the head 
of the bay. The net was stretched across the mouth of the creek for 15 minutes 
during the flood-tide, and two salmon fry were taken, indicating that they run back 
and forth with the tide. 
The fishermen at Marshall, on Tomales Bay, about 20 miles from the mouth of 
Paper-mill Creek, reported having taken young salmon inconsiderable numbers the 
last of April, 1897, about 50 days after they were liberated in the streams near 
Olema. At that time the salmon were about 100 days old and were large enough to 
be taken in the seines used by the fishermen. They caught as many as 15 or 20 at 
a haul for about a week, and caught them occasionally till the middle of June. I 
think the report reliable, as the salmon was a new fish for the bay, and would 
attract much attention. This indicates that the fry may reach the ocean at the age 
of three months. The water at Marshall is pure sea water. 
Specimens have been taken in brackish water in Suisun and San Pablo bays, 
but not enough to determine their movements. A few about 10 weeks old have been 
taken at Benicia in water that was about 20 per cent sea water. 
Effect of sea ivater on alevins and fry. — To determine the effect of sea water on 
alevins and fry, 25,000 eyed eggs were taken from Battle Creek hatchery to the 
Hopkins Seaside Laboratory at Pacific Grove. The eggs were received at the labora- 
tory December 10, 1898, and most of them hatched on the 17th, which date was taken 
as the basis for determining their age in the various experiments. Those not being 
experimented with were cared for as alevins and fry ordinarily are. 
The first experiments were made by putting a few alevins directly from fresh 
water inf o battery jars filled with various mixtures of fresh and sea water. In the 
later experiments glass tanks 2 and 3 feet long were used, and the water was kept 
running. The experiments were begun when the alevins were 6 days old. It was 
found that at this age they could live indefinitely in water that was 25 per cent sea 
water. Those about 40 days old could live in 50 per cent sea water, and at 50 days 
75 per cent. Those 60 days old could live in 95 per cent, though there was consid- 
erable loss. Ninety-live per cent was as nearly pure sea water as could be obtained, 
the laboratory pump being broken and the tank partly filled with fresh water. The 
loss was much less when the density alternated between a high and low percentage, 
which indicates the value of the change of density in the estuaries with the rise and 
fall of the tides. 
When the younger alevins were placed in 50 per cent sea water or stronger, 
the yolk was solidified, becoming much like soft rubber. The blood was driven 
from the body, making it appear bleached, and the adipose membrane at each edge 
of the tail adjacent to the caudal fin turned white. The circulation was retarded 
and the fish became sluggish. The only noticeable effects on the older alevins were 
sluggish movements and an inability to keep a horizontal position. Sometimes 
death was immediately preceded by violent and spasmodic swimming in any and all 
directions. The same actions were noticed in minnows placed in a strong mixture 
of sea water. 
F. C. B. 1902—7 
