River Studies Current Projects
Updated September 2026
Aquatic Assessments at New State Parks
The Centennial Parks Conservation Fund is helping grow Texas’ state parks system, creating new opportunities for Texans to get outside. River Studies is working with partners in Inland Fisheries and State Parks to document the diversity of aquatic species and their habitats on these new properties as they are acquired. These aquatic inventories help state parks staff make informed decisions when developing properties to balance opportunities for the public with conservation of natural resources. Upcoming surveys are planned for Silver Lake State Park and the addition to Lockhart State Park.
Aquatic Bioassessments at Native Fish Conservation Areas
Texas rivers, streams, and reservoirs support 191 species of native freshwater fishes. Nearly half are considered imperiled, highlighting the need for holistic conservation planning. Native Fish Conservation Areas prioritize watersheds throughout the state that are critical to preserving native freshwater fish diversity. In partnership with the University of Texas, aquatic bioassessments target data deficient watersheds and update fish distributions through on the ground fish surveys. These data feed into the Native Fish Conservation Areas prioritization, continually improving our understanding of which watersheds need the most attention. Data has been updated at 513 sites across 21 watersheds under this initiative.
- Upper Frio River Watershed
- Cypress Bayou Basin
- Village Creek Watershed
- Canadian River Basin
- Middle and Lower Neches River Basin
- Upper Red River Basin
- Middle Colorado River Basin
- Litter River Watershed
American Eel Research Program
American Eel, a species of greatest conservation need, has a complex and unique life history. Their lives begin in the Sargasso Sea where adults spawn and larvae begin their journey across the Atlantic Ocean and into rivers from Greenland to South America. Those that end up in Texas have traveled thousands of miles to get here. Despite this incredible life cycle, much about this species in Texas remains a mystery. While East Coast populations support a commercial fishery and have been studied extensively, far less is known about populations in Gulf Coast states. To help fill these gaps, River Studies has partnered with TPWD Coastal Fisheries, University of Houston-Clear Lake, Lower Colorado River Authority, and University of Texas to employ a multi-faceted approach to better understand this species across life stages. This includes soliciting observations from the public, collecting and aging adult eels, and targeting collection of larval eels using eel mops, fyke nets, and eel ramps. This work is responsible for documenting the first larval (glass) eel in Texas. The next phase of the study is to track adult (silver) eels to understand habitat use and timing as they make their way back to the Sargasso Sea to spawn.
- Geographic variation in stable isotope ratios of subtropical American eel
- Eel ramps and environmental DNA reveal a preliminary recruitment window of the American Eel in Texas
Little River Watershed Stream Temperature Study
The Little River, a tributary to the Brazos River in Central Texas, drains nearly 3% of the Texas landscape and supports an impressive diversity of aquatic life. The river is home to 16 species of mussels, one of which is federally endangered, and one is federally threatened. Mussels are filter feeders that provide an outsized service in keeping our rivers clean. To better understand habitat needs of mussels, River Studies has partnered with TPWD’s Science and Water Resources programs to collect data and model instream temperatures at over 50 sites throughout the Little River watershed. This work coincides with efforts to track mussel population trends and detailed water quality data at a subset of sites. Together, these efforts will reveal how stream flow, water temperature, and water quality shape mussel habitat across the watershed. Findings will be used to inform mussel habitat and water quality needs, validate environmental flow standards, inform Sustainable Rivers Program flow agreements, and inform TPWD’s implementation of a 6,000-acre feet of water per year for instream uses within the Brazos River mainstem.
Devils River Fish and Hydrology Monitoring
The spring-fed Devils River flows through southwest Texas into Amistad Reservoir. It is known by many Texans as the most pristine river in the state. Its remote location, exceptional water quality, and complex habitat are home to numerous rare and endemic species. Every other year, River Studies, the San Antoino Fisheries Management District, The Nature Conservancy, and the Devils River Conservancy partner to monitor fish assemblages, sport fish populations, instream habitat, and hydrology. These long-term surveys track changes in fish communities and habitat availability. They also inform water management strategies, sportfish regulations, recreational management, endangered species recovery, land management practices, and conservation planning by Texas Parks and Wildlife, partner organizations, and landowners.
State of the Devils River Report 2024
Cypress Basin Instream Flows Monitoring
Big Cypress Bayou in northeast Texas is a hotspot for biodiversity; however, changes to the landscape and natural patterns of streamflow have altered this dynamic ecosystem, threatening some species that live there. The Sustainable Rivers Program, a collaboration between The Nature Conservancy and the U.S. Army Corps of Engineers, is working to restore the river by adjusting releases from Lake o’ the Pines to mimic a more natural flow regime. This approach balances human and ecosystem needs. Texas Parks and Wildlife Department, alongside many other partners, are supporting this effort by conducting fish, mussel, and habitat monitoring every three years to track ecosystem responses to the new flow regime. This monitoring provides the science needed to refine flow strategies to best meet ecological goals.
