A Re-Analysis of Data and Critique of Medley et al.—“Simulated Transport and Retention of Pelagic Fish Eggs during an Irrigation Release in the Pecos River, New Mexico”

Zymonas, Nikolas D.; Propst, David L.

doi:10.1080/02705060.2009.9664347

Cited by 8 publications

(12 citation statements)

References 10 publications

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“…However, the above studies were based only on modeling the retention of artificially manufactured eggs and did not consider the many factors that long stream fragments can play in the success of these species (Zymonas and Propst 2009). A notable oversight of these studies is the potential for an obligate drifting larval stage, which might contribute to the need for increased longitudinal distances within fragmented streams given that drifting might not cease at the end of the egg developmental phase.…”

Section: Fragmentation Drives Imperilmentmentioning

confidence: 98%

Stream Fragmentation Thresholds for a Reproductive Guild of Great Plains Fishes

2011

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: Impoundments, diversion dams, and stream dewatering have created a mosaic of large river fragments throughout the Great Plains of central North America. Coincident with these habitat changes are massive declines in the distribution and abundance of Great Plains fishes belonging to the “pelagic‐spawning” reproductive guild. We analyzed longitudinal fragment lengths (measured in river kilometers, rkm) and literature accounts of population status for eight species from this guild across 60 fragments to derive thresholds in stream length associated with extirpations. Fragment length predicted population status (F2,21 = 30.14, P < 0.01), with lengths averaging 136 ± 21 rkm for extirpated, 226 ± 69 rkm for declining, and 458 ± 137 for stable populations. Fragment length explained 71% of reported extirpations and estimated thresholds in fragment length explained 67% of variation in population persistence. Our findings provide insight into appropriate spatial scales for conducting riverscape conservation approaches that address the hierarchical effects of fragmentation on stream‐dwelling fishes.

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Section: Fragmentation Drives Imperilmentmentioning

confidence: 98%

Stream Fragmentation Thresholds for a Reproductive Guild of Great Plains Fishes

2011

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“…Other studies have proposed that eddies and other circulation features might retain eggs within a stream reach and thereby dramatically shorten the length of river and flows needed for successful reproduction (Medley et al 2007;Kinzli and Myrick 2010;Widmer et al 2012). The results of these studies have become contentious (see Medley et al 2009;Zymonas and Propst 2009), with major implications for conservation and management planning in watersheds throughout the Great Plains.…”

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confidence: 98%

Sampling Efficiency of the Moore Egg Collector

Worthington¹,

Brewer²,

Grabowski³

et al. 2013

N American J Fish Manag

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Quantitative studies focusing on the collection of semibuoyant fish eggs, which are associated with a pelagic broadcast‐spawning reproductive strategy, are often conducted to evaluate reproductive success. Many of the fishes in this reproductive guild have suffered significant reductions in range and abundance. However, the efficiency of the sampling gear used to evaluate reproduction is often unknown and renders interpretation of the data from these studies difficult. Our objective was to assess the efficiency of a modified Moore egg collector (MEC) using field and laboratory trials. Gear efficiency was assessed by releasing a known quantity of gellan beads with a specific gravity similar to that of eggs from representatives of this reproductive guild (e.g., the Arkansas River Shiner Notropis girardi) into an outdoor flume and recording recaptures. We also used field trials to determine how discharge and release location influenced gear efficiency given current methodological approaches. The flume trials indicated that gear efficiency ranged between 0.0% and 9.5% (n = 57) in a simple 1.83‐m‐wide channel and was positively related to discharge. Efficiency in the field trials was lower, ranging between 0.0% and 3.6%, and was negatively related to bead release distance from the MEC and discharge. The flume trials indicated that the gellan beads were not distributed uniformly across the channel, although aggregation was reduced at higher discharges. This clustering of passively drifting particles should be considered when selecting placement sites for an MEC; further, the use of multiple devices may be warranted in channels with multiple areas of concentrated flow.Received August 8, 2012; accepted October 12, 2012

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“…(Table 1). optimal flow regime for M. aestivalis presumably includes sequential, short-duration flow peaks that maximize retention of pelagicbroadcast propagules (Dudley and Platania 2007;Zymonas and Propst 2009) and likely invigorate ecological productivity (sensu Leigh et al 2010) set apart by intervening flow-recession periods of adequate duration for recruitment (sensu Moore and Thorp 2008). The flow regime associated with highest M. aestivalis recruitment (i.e., 2008) fit this description (Fig.…”

Section: Discussionmentioning

confidence: 80%

Intrafragment riverscape conservation for an imperiled, small-bodied, pelagic-broadcast spawning minnow: speckled chub (Macrhybopsis aestivalis)

Hoagstrom

Archdeacon

Davenport

et al. 2015

Can. J. Fish. Aquat. Sci.

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Intrafragment ecology is little studied for imperiled riverine fishes although river fragmentation and habitat loss increasingly threaten sensitive species. A long-term population-monitoring program in the Pecos River, New Mexico, provided detailed data for 15 annual cohorts of speckled chub (Macrhybopsis aestivalis), which were used to assess intrafragment patterns in recruitment and year-class strength in relation to distributional patterns, flow-regime characteristics, and air temperature. Cohorts avoided a degraded upstream reach. Age-1 and older individuals had distributions consistently centered within a central, relict-ecosystem reach that contained high-quality habitat. Age-0 individuals were widespread within the relict-ecosystem reach and a channelized reach downstream. Distributional patterns suggested that some individuals that recruited in the channelized reach dispersed upstream into relict-ecosystem habitat thereafter. One cohort always numerically dominated the population because cohorts never lived beyond 2 years. Recruitment was density-independent and predicted year-class strength. No aspect of the flow regime explained variation in recruitment. Year-class strength was consistent among cohorts because of densitydependent mortality. High-quality habitat in a centralized location, potential for dispersal between channelized and relictecosystem reaches, and diffuse distribution of pelagic-broadcast propagules throughout both reaches combined to facilitate successful annual recruitment and population persistence.Résumé : L'écologie intrafragment des poissons fluviaux en péril est peu étudiée, même si la fragmentation des cours d'eau et la perte d'habitats menacent de plus en plus les espèces sensibles. Un programme de surveillance à long terme des populations dans la rivière Pecos, au Nouveau-Mexique, a fourni des données détaillées sur 15 cohortes annuelles du cyprinidé Macrhybopsis aestivalis, qui ont été utilisées pour évaluer les motifs intrafragment du recrutement et de la force des classes d'âge par rapport aux motifs de répartition, aux caractéristiques du régime d'écoulement et à la température de l'air. Les cohortes évitaient un tronçon amont dégradé. Les individus d'un an et plus présentaient des répartitions uniformément centrées dans un tronçon d'écosystème relique central renfermant des habitats de bonne qualité. Les individus de moins d'un an étaient répandus dans le tronçon d'écosystème relique, ainsi que dans un tronçon canalisé situé en aval. Les motifs de répartition donnaient à penser que certains individus recrutés dans le tronçon canalisé se dispersaient par la suite vers l'amont dans l'habitat de l'écosystème relique. Il y avait toujours une cohorte dominante dans la population sur le plan du nombre puisque les cohortes ne vivaient jamais plus de 2 ans. Le recrutement était indépendant de la densité et prédisait la force des classes d'âge. Aucun aspect du régime d'écoulement n'expliquait les variations du recrutement. La force des classes d'âge était uniforme d'une cohorte à l...

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A Re-Analysis of Data and Critique of Medley et al.—“Simulated Transport and Retention of Pelagic Fish Eggs during an Irrigation Release in the Pecos River, New Mexico”

Cited by 8 publications

References 10 publications

Stream Fragmentation Thresholds for a Reproductive Guild of Great Plains Fishes

Stream Fragmentation Thresholds for a Reproductive Guild of Great Plains Fishes

Sampling Efficiency of the Moore Egg Collector

Intrafragment riverscape conservation for an imperiled, small-bodied, pelagic-broadcast spawning minnow: speckled chub (Macrhybopsis aestivalis)

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