Seasonal Movements of Invasive Channel Catfish, Ictalurus punctatus, in the San Juan River, New Mexico and Utah

Authors: Keegan Epping, Keith Gido, John Cleveland, Sophia Bonjour, Rachel Grey, Tracy Diver, Stephani Barkalow, Casey Pennock, Justin Furby

Year: 2024

Abstract

Intensive electrofishing has been ineffective at reducing populations of invasive channel catfish, Ictalurus punctatus in the San Juan River, New Mexico and Utah. A better understanding of movement patterns and spawning habitat of channel catfish in this system might provide insight into novel strategies that increase exploitation rates. For example, identifying the timing of synchronized upstream movements might allow concentrated efforts with passive capture gear. We used radio telemetry and Floy-tag recaptures to characterize seasonal movement of channel catfish in the San Juan River. Adult channel catfish captured in a 68-river kilometer reach were surgically implanted with coded radio transmitters in 2023 (n=100) and 2024 (n=96). Tagged fish were located monthly outside of the spawning season and weekly during spawning season with raft-based tracking surveys. Despite a reduced sample size due to a high transmitter shed rate of 59% (n=116/196), we observed a pattern of localized movement in early summer followed by relatively large upstream movement beginning in mid-June in 2023 and mid-July in 2024. Channel catfish > 440 mm TL disproportionately contributed to the observed pattern of upstream movement. Mean net movement of fish <440 mm TL was 4.2 river kilometers and those > 440 mm TL was 14.4 river kilometers. Data from Floy-tag recaptures suggested interannual variation in movement patterns, likely dependent on flow regime. Upstream movement in 2023 largely coincided with back-calculated spawning dates from larval channel catfish, suggesting that upstream movements were spawning migrations. Our data indicate that in some years synchronized spawning movements occur in Spring and early Summer which might increase the vulnerability of individuals to capture, but flow regime will dictate success of removal efforts.