Capturing our Annual Fish Survey

On November 13, Sonoran Institute coordinated the annual fish survey at four locations along the Santa Cruz to determine which species are currently in the river. This multi-partner effort included staff from Arizona Game and Fish Department, Pima County, University of Arizona, U.S. Fish and Wildlife Service, and San Xavier District of the Tohono O’odham Nation.

This survey was done in the Tucson and Marana areas of the Santa Cruz on November 13. Sonoran Institute and partners conducted a similar survey in the Nogales reach of the river on November 12.

The process involves collecting fish by using large nets called seines, and delivering mild electrical shocks and gathering the fish in small nets. We identify each species of fish and count them before returning them to the water unharmed. This gives us a good sense of what types of fish are living in the river and we can compare them over time.

Although this equipment looks similar to a proton pack, we use it to catch fish rather than ghosts.
Cast your nets!
Experts from multiple organizations joined us for the survey.
Using small specimen containers is key for viewing the topminnow and mosquitofish in our survey because it is easier to see the alignment of fins, which is one of many traits used to tell them apart.

Fish in the river indicate the high quality of water being released. Though non-native fish are plentiful, some sites had the endangered Gila topminnow. So native fish are coming back.

Life is able to exist abundantly here because of the clean water released by the Pima County wastewater treatment plants.

Blog Post By: Shane Stanzel, Marketing Intern