Lower Colorado Basin GIS Fish Data
Peter J. Unmack
Arizona State University
Tempe AZ 85287-1501, USA.
Two sets of information are available here, the dataset and the manual. In order to understand the
dataset, you must read the manual as it contains all the documentation of where the data came from,
what the field definitions are, and how to view and manipulate the dataset (if you are unfamiliar
with ArcView). If you have any questions relating to this website or
the dataset please contact Peter Unmack at
The dataset, called coloradofishes.shp can be downloaded from here as
a zip file or as a self extracting zip file. The current version is
dated June 4, 2002. You must also read the documentation available from below. You will need
winzip to open the file, but you probably already have that on your machine. If not go to www.winzip.com and download their free version. You will need ArcView
to view the data. There is a free version called arcexplorer that you can use to view the data in.
It can be downloaded from
http://www.esri.com/software/arcexplorer. I don't think it really matters which
version you download. However, I'd suggest version 2. I do not presently have instructions for
using arcexplorer, hence it could be a little tricky to figure out.
Documentation and Manual
The dataset will allow you to view native and exotic fish records based on
presence/absence from a particular watershed within the Lower Colorado
Basin below Lake Powell, except for Salton Sea. Some additional data are
also included, such as the number of native species by watershed by two
time periods, percentage and absolute decline in natives, and extant
exotic fish records. The dataset can also be manipulated to display
various combinations of the data. Instructions on how to do that can be
The documentation and manual is only available as a single pdf file at
this stage. It can be viewed or downloaded
A copy of the legend file is contained within the coloradofishes.zip file. However, you can also
download a copy of the legend file if you right click here and select "
save link as" (in Netscape), or save target as (in Explorer), which will allow you to save the file
to your hard disk.