134 ILLINOIS ACADEMY OF SCIENCE 



Dace were found spawning in shallow water over gravelly 

 bottoms, in or just above riffles and always with some good 

 retreating place like a deep pool easily accessible. Blunt- 

 nosed Minnows, Kiver Chubs, the two sunflsh, and the 

 Johnny Darter breed in the less rapid stream water, com- 

 monly not far from a foot in depth, and on hard bottoms, 

 usually stony or gravelly and with little sediment. 



Breeding conditions for fish in the streams of the 

 Charleston region are very uncertain. Hard rains raise 

 the streams rapidly and give them an intense turbidity, 

 which is prolonged, although the water goes down quickly 

 and leaves them in their ordinary, sluggish condition. Dur- 

 ing one of these brief freshets, a breeding area may have 

 its character completely changed by the deposition of sedi- 

 ment or rubbish, by the removal of stones, gravel, and other 

 bottom material, and often by a marked change in depth. 

 Many eggs of these stream breeding fish are undoubtedly 

 destroyed, since changes of this nature frequently occur at 

 the principal spawning time in the spring. 



There is considerable difference among our fish as to the 

 way the eggs are cared for after deposition. Some, like the 

 Common Sucker and the Silver-mouthed Minnow, drop 

 them on unprepared bottoms. Some spawn on selected 

 though unprepared areas and guard the eggs there, as Miss 

 Eeeves ('07) found in the case of the Rainbow Darter, 

 where males had '^holdings'' commonly about fifteen inches 

 in diameter. Some fish, like the Stone-roller and the 

 Horned Dace and the sunfish, make structures for their 

 eggs, and these may be called nests. In Illinois there are 

 at least twenty species of fish known to construct nests. 

 Some use natural cavities and depressions for their eggs 

 and appear to do little if any building ; such is the case 

 with the Blunt-nosed Minnow* and the Johnny Darter as 

 far as observed and probably the Channel Catfish (Shira 

 '17a) and the Tadpole Cat, Shilheodcs gyrinus (Hankin- 

 son '08, p. 208). 



The streams ( Map, Fig. 1 ) where most of the field work 

 was done are in the southeastern part of Coles County, Illi- 

 nois, and belong to the Wabash system. Some observations 



*Profes.sor Jacob Reighard writes that breeding Blunt-nosed Minnows ob- 

 served by him usually excavate under stones. 



