Marsh & Associates has been involved in the management of several native fish found in the Gila River basin for over 30 years. The primary objective of the current monitoring program is to detect the presence and distributional extent of focal fish species in over 100 tributaries of the basin.

For over 30 years, Marsh & Associates researchers have been involved with Razorback Sucker population assessments in the lower Colorado River and have ongoing monitoring and survey projects in Lake Mohave.