25 
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 released 99 black bullheads 2 miles above the mouth of the 
Kaskaskia River. On March 16, 1930 Mr. A. J. Nabelrath caught 
three of these tagged bullheads while fishing in Dooley Lake in 
the Kaskaskia bottomlands, 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 regarded 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 pos- 
sible the daily rates given in Table I. For example, carp which 
are 0.42 mile distant after one day are calculated to move 7.0 
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 displacement of 22.5 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 7.05 
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 observa- 
tions 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 placc, several or 
more yards away. Here they may again hesitate and “mill around" 
for a time, and then proceed either leisurely or ina 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. 
