KEOKUK DAM 
101 
the fact that shortly before the gate is lowered the disturbance incident to the filling 
of the lock causes the fish here to become very active. However, the taking of 46 
Ohio shad, all except one from the lock side, indicates that a few individuals of this 
species find their way through the lock; from one to five a day were caught on various 
days from May 4 to July 11. The following may be added as to the species of which 
more than 25 were taken. The shortnose gar was very abundant about Keokuk 
and was found everywhere — river, lake, sloughs, and creeks. The same is true of the 
river quillback, which was, perhaps, the most abundant of all species in the locality 
that year. The spotted cat taken were nearly all small fish, evidently hatched the 
same year or the year before. The drum, like the gar, was very abundant, but par- 
ticularly so in the vicinity of the power house and its accessories. Possibly some of 
the gar and drum taken were engaged in a migratory movement. The extremely 
small number taken of every sort of fish shows that there was no such massed move- 
ment over the upper gate as would have to occur to make the lock an effective fishway. 
CAPTURE OF FISH ON THE UPPER GATE 
Nearly or quite the only reason suggested for considering the lock to be a fish- 
way was the fact that fish were often taken on the upper gate when it was raised. 
(Figs. 10 and 11.) Two stringers, 74 inches (188 centimeters) apart, run the length of 
the gate near its outer edges; the tops of them are 3% inches (8.5 centimeters) above 
the surface of the gate. The surface of the gate between the stringers, being 110 
feet long, has an area of about 678 square feet (63 square meters); this area consists 
of timbers laid with spaces between them, through which the water flows. The gate, 
therefore, is the equivalent of a huge shallow dip net, the stringers restraining the 
fish at the sides, and the length of the gate, as well as the walls, restraining them at 
the ends. The stringers are not the most effective possible restraint on fish, but they 
are high enough to hold some representatives of some species. On July 10, 1915, 
there occurred an opportunity to see how fish are thus held. The emergency or guard 
gate was up and held back the water of the lake, while below it the water level was 
that of the river. The regular upper gate was down and slightly submerged, but 
not deeply enough to have disappeared even in the muddy water of the Mississippi 
River. A German carp within the stringers was swimming back and forth along one 
of them, much like an animal in a zoological park, although by rising slightly it 
might have escaped. 
During 1914, Mr. Huele, the lock master on duty from 8 a. m. to 4 p. m., made 
notes as to the species found on the gate. These notes, contain the names of the 
same species that were taken commonly in 1915 and 1916 and show that very few 
fishes were taken when the water was unusually muddy. 
During 1915 and 1916 a record was kept by the three lock masters of the number 
of fishes taken at all lockages. An effort was made at first to determine the species 
taken, but the gatemen (who reported to lock masters) found that it was impracti- 
cable, in the necessarily rapid work, to distinguish closely allied species. Observa- 
tions made from time to time indicated that species were represented in about the 
same proportions as when the net was on the gate (see p. 100) except that the Ohio 
shad and the river herring were rarely, if ever, captured. Tables 2 and 3 were 
compiled from these special records of fish taken and the regular records of lockages 
made by the lock masters. 
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