rae) 
on 
Evidence that the movements of individual fishes are not 
completely independent of each other is furnished by certain fish 
tag returns. On February 26 and 27, 1950, Mr. Hunt tagged and re- 
leased 99 black bullheads 2 miles above the mouth of the Kaskaskia 
River. On March 16, 1950 Mr. A. J. Nabelrath caught three of these 
tagged bullheads while fishing in Dooley Lake in the Kaskaskia bottom- 
lands, 15 miles upstream. It is clear that these bullheads congregate 
into schools and travel together, since the possibility of three 
fishes being caught on the same day and at the same place after having 
traveled 15 miles by random movement is so remote that it may be re- 
garded as outside the realm of experience. 
If fishes moved in a strictly random manner it would be 
necessary for them to travel, during short periods of time, at 
velocities much higher than the observed velocities to make possible 
the daily rates given in Table I. For example, carp which are 0,42 
mile distant after one day are calculated to move 7.5 feet in one 
second were their motions strictly random. In the same way "fine fish" 
with a daily migration of 1.24 miles are calculated to have a dis- 
placement of 22.3 feet in 1 second. The observed rates over such 
short periods of time are much slower than these calculated rates. A 
carp may swim at the rate of 7.5 feet per second during bursts of 
speed, but none of our fish can reach speeds of 22.5 feet per second. 
This divergence of the observed rates from the calculated rates is 
due to the fact that the movements of fishes are directed over short 
periods of time by environmental influences and due to the fact that 
a fish swims head foremost and is guided as if by a rudder. Direct 
observations of the movements of fishes show that they frequently 
spend considerable time in one place, or within a very circumscribed 
area, and then move rather directly to another place, several yards or 
more away. Here they may again hesitate and "mill around" for a time, 
and then proceed either leisurely or in a rather business-like manner 
in some other direction. The rate of these movements from place to 
place seldom exceeds more than 1 or 2 feet per second unless the 
fishes are frightened or are pursued. 
