COMMON FISHES OF MISSISSIPPI RIVER 
185 
Illinois shore between Hamilton and Warsaw, but young were not taken in the river 
at any other time, although they occurred in several of the few collections that were 
made from creeks. 
The river quillback was extremely common at Keokuk. As reported in a pre- 
vious paper (Coker, 1929), it constituted 48 per cent of all fish taken in the trammel 
net operated on the lock gate in 1915. Its general abundance relative to other 
species was certainly not as high as might seem indicated by that figure, but it is 
believed to have been the commonest fish about Keokuk in that year, except possibly 
one or two minnows. 
In 1916 the German carp and short-nosed gar were present in greater numbers 
than the year before, but the quillback was still very abundant, constituting 42 
per cent of the product of 34 catches that chanced to be observed. Again the per- 
centage figure is probably somewhat misleading, but it is believed that the quillback 
was exceeded in numbers by no large species except the German carp. 
The habits of the fish seem to be unknown. It was found everywhere about 
the plant as well as in other localities, but never in any aggregation suggesting an 
interference with migratory movement. Examples were noted each month except 
December, during which no observations have been made. It appears to be unharmed 
by the dam. 
In some localities fishermen distinguish “white carp” ( carpio ) and “quillback,” 
in others “quillback” and “spearback,” but the applications of the names to the 
respective species is not clear and is probably much confused. It is evident that there 
is a carp sucker most abundant in slack water ( difformis ?) and regarded as trash, and 
another more valuable kind {carpio). We must call attention to the fact that the dis- 
tribution and relative abundance of the several species of carp suckers in the Mis- 
sissippi River and outlying waters has not been made known but offers a promising 
field for study. In nearly all parts of the river the fish of one species or the other are 
extremely abundant. Those of substantial size (above 4 pounds) are of commercial 
value, usually selling as No. 1 fish, some others selling as No. 2 fish, and still others 
being thrown away. It is not even clear that all of the carp suckers have an indirect 
economic value as food of other fishes. 
