NATURAL HISTORY OF THE QUINN AT SALMON. 
87 
At any time during the four weeks that the fry were so crowded in the pond they 
could have gone out, as the overflow trough was unobstructed. Very few if any of 
them did so, however. Indeed, it was difficult to get them to go out at all, very few 
escaping till nearly all the water was drawn off. As soon as they came near enough 
to the overflow to feel the course of the current they would dart back into the pool 
again. It has often been noticed that fry have an aversion to going over a water- 
fall or swift rapid, 'flic observations at Sims during the summer of 1898 indicate 
the same thing. On account of this, fry should not be planted above falls or swift 
rapids, especially in small streams, as it is desirable that they should move down- 
stream as soon as possible. 
Observations of a particular fry . — Fry were observed daily from September 18 to 
October 3, 1900, in a pool between a rock and the shore in Battle Creek. The pool 
was about 18 inches across, 4 feet long, and 2 or 3 feet deep. There was but one 
fry until the 25th, when another appeared. It is probable that only two individuals 
were seen during the observations, though we can not lie sure that such was the case. 
When first seen the fry swam near the surface, but after a few days it remained 
a few inches below. It stayed most of the time in the rather strong current, and 
was continually snapping at minute floating objects. When swimming near the 
surface it made from two to ten strikes a minute. Observations could not be made 
so easily after it began swimming deeper. It was seen to make at least 150 strikes, 
but each time whatever was caught was immediately ejected. Apparently it had to 
make a great many efforts before finding anything edible. 
One of the fry was seen to leave the pool and resume its migration. It had 
been in the lower portion of the pool all day, and as evening approached allowed 
itself to be carried down into the shallow and swift water of the outlet, always 
keeping its head upstream. Several times it was carried halfway through the out- 
let, but darted back into the pool. Once it got entirely through the outlet and into 
the deep water below the rock and then darted back, but finally it was carried out 
into the main current, tail first, and was lost sight of. 
Enemies. — As already stated, 855,000 young salmon were planted in the streams 
of Marin County, Cal., in 1S97, after having been kept in the hatchery until the 
yolk-sac was absorbed and I hey had begun to feed. In order to determine to what 
extent they were preyed upon by the other fishes of the stream, large numbers of 
trout and a few sculpins ivei’e caught and examined, being the only fishes in the 
stream that could be suspected of eating salmon fry. Beginning at the time the 
plants were made and continuing for three weeks, 30 or 40 trout, ranging from G to 
10 inches in length, were daily caught and examined. In not one instance had a 
salmon been eaten. The only fish eaten by them was the small minnow (Rutilus 
symmetricus) , and no more than 10 of these were found in about 700 trout examined. 
Of the sculpins ( Coitus gulosus), only 25 of size large enough to eat a salmon fry were 
caught. None of these had eaten fish of any kind. 
In 1898, after the young salmon planted that year had absorbed the yolk-sac, a 
number of trout were examined. None were found to have eaten salmon fry. 
On one occasion a small pool 8 feet across and about 18 inches deep was seined. 
Over 100 young salmon were caught, averaging 2.1 inches in length. Along with 
them about a dozen trout from 6 to 8 inches long were taken. It would seem that 
if ever trout ate young salmon it would be here. These trout were examined, and 
