The critical importance of an undammed river segment to the reproductive cycle of a migratory Neotropical fish

N American J Fish Manag

McKinstry

MacKinnon

et al. 2019

The extent of fish movements in contemporary river networks can depend on spatial position relative to attractive features that may provide food and refuge, such as tributary mouths, or restrictive features, such as barriers. From the San Juan River basin in New Mexico and Utah, we integrated remote summertime PIT tag detections at two tributary mouths (McElmo Creek and Chaco Wash) with main‐stem recapture data from 2012 to 2015 to determine if two endangered species, Colorado Pikeminnow Ptychocheilus lucius and Razorback Sucker Xyrauchen texanus, differed in tributary use, demography, and seasonal ranges. Razorback Suckers were more abundantly detected (n = 266 individuals) and recaptured (n = 145) than were Colorado Pikeminnows (n = 96 detected; n = 55 recaptured). Despite the San Juan River flowing uninterrupted between the tributary mouths, individuals of each species separated into tributary‐specific groups. Razorback Suckers had very similar sizes and ages at each tributary, reflecting a homogeneous augmented population. Colorado Pikeminnows separated into tributary‐specific groups of either adult (Chaco Wash) or subadult (McElmo Creek) fish based on total length and age. Analyses suggested that fish size was a significant factor explaining the extent of seasonal ranges for both species. Although the ranges of both species exhibited a tributary effect, this effect was more significant in explaining Razorback Sucker ranges than Colorado Pikeminnow ranges, which were explained best by season. Understanding how mobile species interact with attractive and inhibitive river features can help managers identify potential sampling biases along with possible consequences of spatially structured populations. Managers should consider extending sampling upstream of barriers, installing additional permanent antenna arrays, and maintaining perennial flows in these tributaries.

Section: Discussionmentioning

confidence: 99%

“…; Lopes et al. ), communities (Osborne and Wiley ), and geomorphological processes throughout river networks (Benda et al. ; Kiffney et al.…”

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confidence: 99%

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confidence: 99%

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

N American J Fish Manag

McKinstry

MacKinnon

et al. 2019

“…; Lopes et al. ). Moreover, corridors connecting spatially structured populations have been compromised by dams or diversions, leading to diminished survival of juveniles or failure to access spawning habitats by adults (Marschall et al.…”

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confidence: 98%

“…; Lopes et al. ). This suggests that connectivity and increased available river habitat can benefit spatially structured populations.…”

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confidence: 98%

Spawning Locations within and among Tributaries Influence Flannelmouth Sucker Offspring Experience

Gido

Brandenburg³

2019

Trans Am Fish Soc

Migratory fishes often spawn across broad spatial scales to limit intraspecific interactions among mature and immature individuals, leading to long‐distance movements of both adults and offspring. Thus, offspring are potentially exposed to a range of environmental conditions throughout their development that affect growth, survival, and recruitment. Migratory suckers (family Catostomidae) can be used to test spatial variation in early life stage experiences for iteroparous fishes. We use the Flannelmouth Sucker Catostomus latipinnis, a fish that is endemic to the American Southwest, to illustrate how larval and juvenile stages are affected by the distance of upstream spawning migration in tributaries that vary in flow regime and habitat availability (i.e., perennial versus intermittent streams). Remote detection of PIT‐tagged migrating adults indicated that spawning and larval rearing sites were distributed over 32 km within McElmo Creek, a perennial tributary to the San Juan River, Utah. Physical sampling of an upstream intermittent tributary, the Mancos River, New Mexico showed that spawning adults—and then larvae—were restricted to within 1 km of the main‐stem river. Quantile regression demonstrated recruitment of larvae to the juvenile stage was significantly (i.e., up to 2 weeks) faster in more upstream reaches of the perennial tributary, potentially due to more constant thermal regimes. Spatial differences in animal community structure at sites with larval Flannelmouth Sucker indicated that the potential for predation and competition was greatest in upstream reaches. Small, rare, and even intermittent tributaries concentrate spawning activity that dictates larval sucker experiences. Conserving, maintaining, and enhancing connectivity via flows synchronized with spawning and rearing are critical steps to protect migratory suckers in arid environments.

Movement ecology of imperilled fish in a novel ecosystem: River‐reservoir movements by razorback sucker and translocations to aid conservation

Pennock

McKinstry

et al. 2020

Aquatic Conservation

Reservoirs and associated river fragments are novel ecosystems not experienced by fishes in their evolutionary history, yet they are now commonplace across the globe. Understanding how fishes use these novel habitats is vital to conservation efforts in contemporary riverscapes. Movement patterns of the endangered razorback sucker (Xyrauchen texanus) synthesized from tagging efforts in the upper Colorado River basin, USA, illustrate the applications of tagging technology and data sharing by multiple agencies to better understand the spatial ecology of large river fishes. Tagging studies between 2014 and 2018 in Lake Powell and its two main tributary rivers, the Colorado (unfragmented) and San Juan (waterfall‐fragmented), were used to quantify movement of razorback sucker within this river–reservoir habitat complex. In addition, facilitated translocations of fish upstream of a waterfall barrier in the San Juan River were assessed in 2016–2017. Extensive movement of fish occurred within and across river and reservoir habitats. Of 722 fish captured in the Colorado River arm of Lake Powell, 36% of re‐encounters occurred upstream in the Colorado or Green rivers, or fish dispersed through the reservoir and were detected in the San Juan River arm. Fourteen fish moved more than 600 km. In the San Juan arm of the reservoir, 29% and 20% of fish in 2017 and 2018, respectively, had moved ~30–40 km upstream below the waterfall in the San Juan River within a year. In 2016–2017, 303 fish were translocated upstream of the waterfall into the San Juan River, but 80% were re‐encountered downstream of the waterfall within a year. Long‐distance movements by razorback sucker were common within and among rivers and reservoirs illustrating how large river fish, in general, might maintain population connectivity in highly altered ecosystems.