Fish Community Distributions and Movements in Two Tributaries of the San Juan River, USA

Abstract

Recognizing how stream fish communities-and their habitats-differ across space and time relative to their position in stream networks (i.e., main-stem versus tributary habitats) is increasingly important for the conservation of imperiled native fish communities in altered river networks such as those in the Colorado River basin. We studied the patterns (community composition) and processes (movements) that shape species occurrences and distributions in two tributaries of the San Juan River, Utah and New Mexico, between 2012 and 2014. Our results show that distance from the San Juan River was a strong driver of tributary fish community structure, whether through declines in species richness (Chaco Wash) or species turnover (McElmo Creek), and that these patterns coincided with habitat gradients (i.e., depth, substrate, and width). Occurrences of passive integrated transponder (PIT)-tagged fish at a stationary antenna in McElmo Creek just upstream of its confluence with the San Juan River varied by species but generally were associated with spring spawning migrations (Flannelmouth Sucker Catostomus latipinnis, Razorback Sucker Xyrauchen texanus), exploratory movements (Colorado Pikeminnow Ptychocheilus lucius), and monsoon flooding (Channel Catfish Ictalurus punctatus, Razorback Sucker). Occurrences of PIT-tagged fish in Chaco Wash were dominated by endangered Razorback Suckers and Colorado Pikeminnows, suggesting that this habitat supplies useful habitat, forage, or both. Given the common occurrences of native fishes in these tributaries, incorporating these habitats into basinwide management actions seems necessary to fully understand the spatiotemporal dynamics of native and nonnative fish communities.

Dynamic contributions of intermittent and perennial streams to fish beta diversity in dryland rivers

“…Rapid recolonization of formerly dry habitat is likely to occur after the cessation of drought (Lennox, Crook, Moyle, Struthers, & Cooke, ). High flow events are known to induce dispersal of native fishes elsewhere in the Colorado River Basin for increased foraging, spawning, or exploring activities (Booth, Flecker, & Hairston, ; Cathcart, Gido, & McKinstry, ; Cross et al, ), leading to decreased probability of local extinction (Budy, Conner, Salant, & Macfarlane, ). Years with the highest flow anomalies are also times when extreme spring floods or summer monsoons have occurred, and may have been detrimental to non‐native species populations (Bestgen, Wilcox, Hill, & Fausch, ; Gido, Propst, Olden, & Bestgen, ; Rogosch et al, ).…”

“…Pool & Olden, ). Consequently, native species persistence may be vulnerable for species that increasingly rely on intermittent tributary habitats to provide refuge from non‐native fishes (Bottcher, Walsworth, Thiede, Budy, & Speas, ; Cathcart et al, ).…”

A Tribute to Tributaries: Endangered Fish Distributions within Critical Habitat of the San Juan River, USA

“…) and Razorback Suckers (Cathcart et al. ) is often noteworthy, seldom do studies test how these habitats may benefit them beyond seasonal and opportunistic occupancy or movements, especially in a comparative manner. This is important to consider since riverine fish populations and communities worldwide have been shown to be structured by tributaries and their confluences that can provide migratory routes, spawning or rearing locations, and refugia connected to main‐stem streams (Brown and Coon ; Fernandes et al.…”

“…McElmo Creek drains an area of 1,818 km² in Colorado and Utah and joins the San Juan River 163 km upstream of the waterfall near Aneth, Utah (Cathcart et al. ). The tributary confluences are separated by 81 km of the San Juan River.…”

Flannelmouth Sucker: The Ironhorse of the Colorado River Basin

“…In McElmo Creek, these February and March migrations of thousands of individuals occur when temperatures exceed 5°C and can cover in excess of 35 km (Cathcart et al 2015(Cathcart et al , 2018. In McElmo Creek, these February and March migrations of thousands of individuals occur when temperatures exceed 5°C and can cover in excess of 35 km (Cathcart et al 2015(Cathcart et al , 2018.…”