A distributional atlas of Upper Mississippi River fishes

and habitat alteration in the Mississippi Ri\er prompts us to publish information we have assembled on the present distribution of fishes in that river.Since 1962 a concerted efTort, under the aegis of the Upper Mississippi River Conservation Committee (hereafter UMRCC), has re- sulted in a vast quantity of distributional data, and its publication can provide a criterion that will aid in the detection and measurement of future changes in the en- vironmental quality of the river.