Ecology of the Central Mudminnow, Umbra limi (Kirtland)

Abstract

Ecological studies of the freshwater fishes are far from complete. Studies relevant to the life history of the Unibridae are particularly lacking. This fact, plus the presence of a large local population of Umbra limi, prompted this investigation. Our study of the ecology of the central mudminnow was concentrated on a population from Judy Creek, a small stream in St. Joseph County, Indiana, which empties into the St. Joseph River north of South Bend, Indiana. The stream is approximately 10 miles in length and 20 feet at its widest part. It is a favorite trout stream of the locality and is stocked periodically. In the area of the stream where the mudminnows are plentiful, approximately one mile northeast of the University of Notre Dame campus, the bottom consists of sandy loam with moderate amount of aquatic vegetation along banks. Throughout the greater part of the year the stream has a maximum depth of from 2 to 3 feet. From the mouth of the stream to a point approxiimately 4 miles upstream, it is rock-strewn with very little aquatic vegetation, and the mucdminnow is noticeably absent. Similarly, the mudminnow is scarce at the headwaters of the stream where the depth of the water is less than one foot.