Factors Influencing Rainbow Trout Annual Growth in a Large Regulated River

Dunnigan, James L.; Terrazas, Marc M.

doi:10.1002/tafs.10278

Cited by 3 publications

(3 citation statements)

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“…The emigration timing of hatchery-released juveniles and river conditions (e.g., water temperature and flow) during emigration are among many factors affecting downstream survival, size and age at maturity, and adult return rates. Flow manipulations in impounded systems like the Columbia River that change the timing, duration, or magnitude of temperature and flow regimes may impact growth rates (Dunnigan and Terrazas 2021) and in the spring can significantly affect the emigration of salmonid smolts. Increased natural flows (e.g., spring freshets) encourage emigration, reduce travel times, and can improve survival of juvenile Chinook Salmon (Connor et al 2003;Sommer et al 2005;del Rosario et al 2013;Takata et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Effects of volitional emigration timing and smolt size on survival and age-at-return in a Pacific salmon hatchery population

et al. 2023

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Many Pacific salmon populations are returning from sea at younger ages and smaller sizes. Hatchery culture, management practices, and environmental factors influence juvenile release size and emigration timing, which in turn affect important demographic characteristics in returning adults. We analyzed data from approximately 345,000 tagged spring Chinook Salmon juveniles exiting Cle Elum Supplementation and Research Facility (Yakima River, Washington, USA) acclimation sites over thirteen brood years (2002–2014), evaluating smolt size, emigration timing, river flow, juvenile survival, and age-at-return. We observed a relationship between size and volitional exit timing of smolts from acclimation sites, with larger fish tending to emigrate earlier than smaller fish. Early emigration was also coincident with lower river flows near acclimation sites. Later emigration timing was correlated with an increase in apparent survival of juveniles to Bonneville Dam (500–530 km downstream of acclimation sites), but also with a lower rate of survival to return from sea. In general, for juveniles successfully emigrating downstream of Bonneville Dam, age-at-return increased with decreasing juvenile fish size and later emigration timing. Our results support a growing body of evidence that hatchery practices may result in larger smolts that tend to return at younger ages. Given the biological and economic consequences of younger age-at-maturation, methods to reverse this trend should be further explored and implemented.

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Section: Introductionmentioning

confidence: 99%

Effects of volitional emigration timing and smolt size on survival and age-at-return in a Pacific salmon hatchery population

et al. 2023

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“…2016), but effects may be seasonal or life stage dependent and may not translate to other salmonid species (i.e., Rainbow Trout; Dibble et al. 2015; Dunnigan and Terrazas 2021). Food resources and metabolic conditions may be dependent on seasonal fluctuations in river discharge, and the density of conspecifics may limit growth (Krause et al.…”

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confidence: 99%

“…River discharge patterns influence population demographics (McKinney et al 2001;Dibble et al 2015;Dreves et al 2016). For instance, increased magnitude of annual river discharges may result in greater growth of Brown Trout (Dreves et al 2016), but effects may be seasonal or life stage dependent and may not translate to other salmonid species (i.e., Rainbow Trout;Dibble et al 2015;Dunnigan and Terrazas 2021). Food resources and metabolic conditions may be dependent on seasonal fluctuations in river discharge, and the density of conspecifics may limit growth (Krause et al 2005;Johnson et al 2006).…”

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confidence: 99%

Trout Responses to Stocking Rates and River Discharge within a Southeastern U.S. Hydropeaking Tailwater

Spurgeon

Kaiser²,

Graham³

et al. 2022

N American J Fish Manag

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Freshwater fish populations often exist in systems characterized by novel ecological processes resulting from human alteration. Salmonid populations embedded within coldwater sections of warmwater rivers are spatially constrained by habitat availability. Tailwater fish contend with fluctuating river discharges and density-dependent processes associated with fish stocking and exploitation. Salmonid populations sustained through stocking versus natural reproduction may respond differently to changes in hydrologic patterns (e.g., hydropeaking) as well as declines in fish abundance. We assessed differences between stocked (Rainbow Trout Oncorhynchus mykiss) and naturalized (Brown Trout Salmo trutta) trout populations in Greers Ferry tailwater, Arkansas, regarding (1) spatial and temporal patterns of mean length, electrofishing catch rates, and relative condition following reduced number of stocked Rainbow Trout and (2) evidence that hydrologic characteristics and fish stocking intensity influenced relative condition. A 56% reduction in Rainbow Trout stocking did not result in systemwide change in mean length or relative abundance for Rainbow Trout or Brown Trout over the 16-year study period. Hydrologic variability, where river discharge spanned both reduced and elevated levels, positively influenced condition of both Rainbow Trout and Brown Trout. Assessment of survival of stocked Rainbow Trout may aid in further refining the timing and amount of stocking needed to sustain the population at a desired abundance. Further, assessing the influence of stocking fewer but perhaps larger (in terms of mean length) fish to meet management goals may be warranted. The persistent differences in relative abundance among river sections can inform management actions directed at Brown Trout, including harvest regulations. Such regulations may aid in reaching desired management goals, including abundance and mean length targets not observed after reduced stocking.Human alteration of riverine environments necessitates that fisheries managers work in systems with novel and often bounded ecosystem processes (Moyle 2014). Tailwaters, defined here as the area below impoundments characterized by hydrologic and thermal processes not persistent under unaltered river conditions, are one example of novel ecosystems that are managed to meet human needs, including for electric power production and recreational

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Consequences of nuisance algal blooms of Didymosphenia geminata on invertebrate communities in Rocky Mountain streams

Brogan,

Peckarsky,

Resasco

2024

Freshwater Science

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Factors Influencing Rainbow Trout Annual Growth in a Large Regulated River

Cited by 3 publications

References 81 publications

Effects of volitional emigration timing and smolt size on survival and age-at-return in a Pacific salmon hatchery population

Effects of volitional emigration timing and smolt size on survival and age-at-return in a Pacific salmon hatchery population

Trout Responses to Stocking Rates and River Discharge within a Southeastern U.S. Hydropeaking Tailwater

Consequences of nuisance algal blooms of Didymosphenia geminata on invertebrate communities in Rocky Mountain streams

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