Water Resources of Idaho

Assessment of Fish Assemblages and Minimum Sampling Effort Required to Determine Biotic Integrity of Large Rivers in Southern Idaho, 2002
by T.R. Maret and D.S. Ott

Water Resources-Investigations Report 03-4274

This document was created as a PDF document. It can be viewed with Acrobat 3.0 or higher.

A critical issue surrounding biomonitoring in large rivers is the minimum sampling-reach distance required to collect an adequate number of fish to represent the fish assemblage within a reach. Excessive sampling effort is costly in terms of work hours, reduces the number of sites that can be visited, can compromise field-crew safety, can be logistically unfeasible, and can cause unnecessary injury to captured fish. On the other hand, inadequate sampling effort can produce considerable variability in multiple samples collected at a site and may underrepresent the species or river condition present. This report identifies the minimum reach length required to collect a sample population of fish representing the greatest percentage of species within a reach. The study was done for the U.S. Environmental Protection Agency’s Environmental Monitoring and Assessment Program in southern Idaho.

This report is only available on line -- view report (1001K). For further information concerning this report please contact Terry Maret by phone at (208)387-1328 or trmaret@usgs.gov. If you encounter problems viewing this report please contact Linda Channel by phone at (208)387-1305 or email at lchannel@usgs.gov.