Award Date


Degree Type


Degree Name

Master of Science (MS)


Biological Science

First Committee Member

James E. Deacon

Number of Pages



Fish assemblages in 22 pools were sampled over the summer of 1997 in the North Fork of the Virgin River, Zion National Park, Utah, to assess effects of recreational activities on native fish communities. Pools experiencing high levels of wading and float tubing contained altered population distributions and altered community structure as compared to pools generally lacking recreational activities. In addition, pools disturbed by recreation had lower abundance of desert sucker (Catostomus clarki) and lower community diversity than pools without recreation. Food availability measured as algal biomass and macroinvertebrate drift density was similar among all pools, but abundance of larval fish was lower in pools experiencing recreational disturbance. Flash floods at the end of the summer appeared to "reset" the system, redistributing fish in the river and resulting in similar communities throughout the study area. Results suggest that recreational activities do disturb native fish communities and that the greatest threat may be to larval fish.


Community; Desert; Detecting; Disturbance; Ecological; Effects; Environmental; Fish; Impact; Recreational; Stream; Utah

Controlled Subject

Ecology; Environmental sciences; Recreation; Aquatic sciences

File Format


File Size

1218.56 KB

Degree Grantor

University of Nevada, Las Vegas


If you are the rightful copyright holder of this dissertation or thesis and wish to have the full text removed from Digital Scholarship@UNLV, please submit a request to and include clear identification of the work, preferably with URL.


IN COPYRIGHT. For more information about this rights statement, please visit