Background:
In 2000, the Arizona Game and Fish Department began a long-term monitoring program funded by Grand Canyon Monitoring and Research Center (http://www.gcmrc.gov/) to monitor fish relative abundance and distribution throughout Marble, Glen and Grand Canyons.  It was originally designed to focus on rainbow trout, brown trout and commoncarp, but we have found that it is also a useful tool to monitor native flannelmouth and bluehead suckers.  The project utilizes standardized, non lethal, electroshocking to provide an index of relative abundance, distribution, and cohort strength for several species of fish that currently occupy the canyon.  It is also utilized to detect non-native species that are currently not abundant within the canyon but pose a threat to native fish if they become established.

Location:
This monitoring effort takes place on the Colorado River and extends from Lees Ferry (15.5 miles downriver of Glen Canyon Dam) downstream 270 miles to the Lake Mead National Recreation Area.

Approach:
The Research Branch of the Arizona Game and Fish Department currently conduct two trips each spring as part of a long term monitoring project.  Approximately 800 sites are electrofished each year.  All fish collected during each sampling trip are measured, weighed, and checked for sexual maturity.  All native fish larger than 6 inches are implanted with tiny microchips, which allow us to identify individual fish and gather information on growth and movement if the fish is ever captured again.  We conduct our sampling at night because fish tend to move towards the shoreline after sunset, and electrofishing is most effective in shallow water.  All of this information is used to evaluate trends of native and non-native fish in the canyon.  In 2008 this program was used to determine the status of rainbow trout prior to, and after the High Flow Experiment (HFE).

Benefits:

The data collected from each sampling trip enables us to detect changes in the fish community over time.  From these data, management decisions can be implemented to benefit Grand Canyon fishes.  Data are used to advise the Secretary of the Interior on operations of Glen Canyon Dam through the Glen Canyon Adaptive Management Program.

COR Downstream Annual Report 2003

For more information contact:
Aaron Bunch, Arizona Game and Fish Department
506 N. Grant St. Suite L, Flagstaff, AZ 86001. 
Phone: (928) 226-7677    E-mail: abunchagf@qwestoffice.net

Bill Stewart, Arizona Game and Fish Department
5000 W. Carefree Highway, Phoenix, AZ 85086
Phone: (623) 236-7368    E-mail: bstewart@azgfd.gov

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