The Razorback Sucker is endemic to the Colorado River basin and protected under the Endangered Species Act. Once found throughout the warm water reaches of the basin, the Razorback Sucker’s basinwide decline is believed to be a result of myriad anthropogenic habitat alterations and negative interactions with introduced fishes. Razorback Sucker spawning occurs as spring runoff increases river discharge. Upon hatching from eggs deposited in river substrate, larvae drift with river current into flooded off-channel nursery habitats. Despite ongoing stocking of Razorback Sucker into the Colorado River, studies show that natural recruitment necessary for self-sustaining wild populations is lacking, and populations in the upper Colorado River continue to require maintenance via stocking of adult fish.
A stretch of 64 miles of the Colorado River between Moab and the confluence with the Green River has been identified as a priority reach for recovery of Razorback Sucker. The Matheson Preserve is the only site within this reach capable of providing suitable nursery habitat as identified in recovery goals. However, the Matheson Preserves’ current value to razorback recovery limited by an abundance of non-native fishes and reduced frequency and duration of flood events.
Competition and predation by non-native fishes are linked to reduced survival and growth rates of stocked Razorback Sucker larvae in wetlands, potentially resulting in total mortality. However, experimental survival rates of Razorback Sucker larvae in ‘reset’ floodplains (i.e. those free of non-native fishes at entrainment) are thought adequate to sustain populations and age-zero Razorback Sucker in floodplain environments outgrow predation risk from non-native fish spawned in the same year. Thus, a combination of ‘reset’ conditions and exclusion of all but larval non-native fishes during inundation should contribute to optimal Razorback Sucker survival.
In recent years, overbank flows of the Matheson Preserve occur infrequently; approximately once each decade. Discrete portions such as the Central Pond, however, achieve connection through gated canals at lower flows. In light of the recently documented presence of wild Razorback Sucker larvae at the mouth of the Central Pond inlet, the Central Pond was modified to achieve inundation in three of every five years and to drain completely (i.e. achieve ‘reset’ conditions) and concurrently integrate a redundant fish exclusion apparatus and improved head gate for water level management. Additional water sources to maintain adequate levels in the entrainment area are diverted to entrainment area from naturally occurring springs located on the north-west end of the preserve. We believe that management of the Central Pond with this suite of features can contribute significantly to the recovery of Razorback Sucker.
This project provides a functional, floodplain wetland that offers Razorback Sucker, as well as other native fish including Bluehead Sucker, Flannelmouth Sucker, Roundtail Chub, and Bonytail Chub, suitable nursery habitat during spring flooding, as well as offering other ecological benefits to the Matheson Preserve. Floodplain connectivity has been restored in a variety of flow scenarios, entrainment of wild Razorback Suckers into the Central Pond has been documented, large bodied non-native fish are excluded, water quality and quantity is maintained for sufficient amounts of time post-entrainment to ensure survivability and growth of larval Razorback Sucker, and juveniles were successfully released back into the Colorado River.
The Matheson Wetland Preserve is also considered an outdoor classroom.
Located near Moab, Utah, several teachers bring their students to the Matheson Preserve, particularly fourth-grade students who visit the preserve during August or September to do hands-on science activities that align with Utah’s core science curriculum. This curriculum includes the study of wetlands. The Matheson is also used as an outdoor classroom for local groups such as the Girl Scouts of the USA. In May, for International Migratory Bird Day, there is a public event held on the preserve where local fisheries experts for the DWR discuss the endangered species of the Colorado River and the ongoing project.
In the spring of 2019, larval Razorback Sucker were spotted in the Colorado River adjacent to the wetlands and were successfully entrained into the Matheson Preserve via the partially completed backwater channel. In the fall of 2021, the first juvenile Razorback Suckers that reared in the Matheson Preserve were successfully released back into the Colorado River
Select media resources about the project: