| GIS (ERSI ArcGIS ver 9.2) was used to identify streams occurring on the Tonto (TNF) and Santa Fe National Forests (SFNF). Using GIS, streams were segmented into reaches based upon gradient. The categories were: 0 to 2.0%, 2 to 2.5 %, 2.5 to 3.0%, 3.0 to 3.5%, and > 3.5%.
GIS was used to convert stream vertices to points and then extracted elevation levels from 10 meter DEMs using an interpolation method and assigned point elevations back to stream segments. For each stream segment this generated a maximum/minimum elevation and length allowing to calculate rise over run using this GIS data.
Data from stream reach gradients generated in the GIS was compared to previously collected empirical field data on stream reach gradient, fish distribution, and species composition. We found a positive correlation between field data and data generated by the GIS.
We believe that using GIS provides a valuable time saving tool to assist researchers and managers to maximize catch per unit effort. Often times field studies are costly or man power is unavailable for surveying. Using GIS could aid managers in predicting fish species composition and distribution when field seasons and/or funding is limited.
The next step in the process is to use this GIS data to identify stream gradients, predict fish species composition, and distribution prior to conducting field sampling in streams not previously surveyed to validate predictions.
Abstract presented at the Fourth International Symposium on GIS/Spatial Analysis in Fishery and Aquatic Sciences in Rio de Janeiro, Brazil, from 25–29 August 2008. | 
