Movement of fishes in a San Juan River tributary network: When, Where, and Why

Authors: C. Nathan Cathcart, Keith B. Gido, Mark C. McKinstry

Year: 2013 (xlv)

Abstract

Researching fish movements throughout the Colorado River Basin has been a useful tool for managers and ecologists. Knowing when and where fish appear in a stream can generate hypotheses seeking to understand why they are there (i.e., to spawn, feed, seek refuge, etc.) as well as management actions tailored to species and habitats. Specific habitats, such as confluences, provide insight into fish movement strategies because they can be a complex habitat serving as the explicit junction of two different streams with differential potential to support various life histories of species. To explore the influence confluence zones have in the interpretation of tributary network habitats by seven fish species, we relied on Passive Integrated Transponder (PIT) technology to remotely monitor movement of the large bodied fish community at strategic locations in McElmo Creek, Yellow Jacket Creek and the San Juan River in 2012 and 2013. A fish community-wide tagging approach of fishes greater than 115 mm across a broad spatial scale enabled us to address pertinent federal and state management goals in the San Juan River basin including: conserving endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus); monitoring population trends of roundtail chub (Gila robusta), flannelmouth sucker (Catostomus latipinnis), and bluehead sucker (Catostomus discobolus); and managing nonnative species such as channel catfish (Ictalurus punctatus) and black bullhead (Ameiurus melas). Seasonal patterns at the junction of McElmo Creek and the San Juan River appear to be driven by spawning for razorback and flannelmouth suckers and monsoon-influenced discharge patterns for channel catfish. Movement patterns at the confluence of Yellow Jacket and McElmo creeks are differentiated by body size, species, and the monsoons. We offer management implications related to species management objectives with their respective species and habitats. From an applied and basic ecological perspective, study designs incorporating several species within the community, especially long-lived species, as well as broad spatial scales can enhance our understanding of movements through quantification and classification of movement patterns. Similarly, studies that span political boundaries and merge management priorities promote collaborative efforts that enhance progress toward multiple objectives.