The use of floating overhead cover by warmwater stream fishes

Abstract

Increasing the amount of woody debris in streams has often increased population size of one or more focal species whereas clearing a stream of woody debris has often reduced populations. Alterations of the amount of woody debris change multiple aspects of the habitat simultaneously, so it is very difficult to know what particular stimulus or combination of stimuli evoked the changes in the fish populations. The purpose of this research was to alter habitat by the addition of overhead cover alone, and to see whether or not that single change would affect the distribution of stream-dwelling fishes. The addition of solid, floating cover objects 1.8 m by 2.4 m resulted in increased local populations of bluntnose minnow (Pimphales notatus), creek chub (Semotilus atromaculatus), and longear sunfish (Lepomis megalotis) five to six weeks later, but did not change the distribution of four other species: white sucker (Catostomus commersoni), green sunfish (Lepomis cyanellus), bluegill (Lepomis macrochirus), and largemouth bass (Micropterus salmoides). These results showed that for some species at least, changes in channel morphology, visual isolation, and amelioration of flow produced by adding three-dimensional complex woody debris were not essential for making locally attractive habitat changes in a warmwater stream. The effectiveness of overhead cover as used here would be expected to vary for different species and depend on such things as predation threat, flow, and food levels.Keywords Overhead cover Á Warmwater fishes Á Habitat preferencesThe addition of woody debris to streams has often enhanced habitat and increased fish populations

Association of an endemic leuciscid, the Sandhills Chub, with microhabitat features and watershed‐level habitat characteristics

“…The Creek Chub Semotilus atromaculatus , a congener of the Sandhills Chub, was demonstrated to be highly associated with instream cover, such as woody debris and aquatic vegetation (Belica and Rahel 2008). Gatz (2008) reported that the addition of woody debris into a stream in central Ohio significantly increased the total number of Creek Chub found within an experimental reach. The addition of woody debris as instream cover is common in stream restoration and conservation efforts that are focused on improving habitat for salmonid populations (Lehane et al 2002; Sweka and Hartman 2006).…”

Use of Natural and Added Cover Types by Game and Nongame Fishes in a Great Plains River

“…In Jordan Creek, a warmwater second‐order stream in Illinois, Angermeier and Karr () observed lower overall abundances of cyprinids in the “cleared” side of an experimental reach compared to an adjacent side containing added wood structures. In Delaware Run, a warmwater stream in Ohio, the distribution of Creek Chub and Bluntnose Minnow Pimephales notatus was positively affected by the presence of overhead cover provided by wood additions (Gatz ). The one species in our study that showed no selection for either natural or added wood was the Johnny Darter, which was mainly caught in open‐water habitat.…”