Spatiotemporal Population Trends of Notropis simus pecosensis in Relation to Habitat Conditions and the Annual Flow Regime of the Pecos River, 1992–2005

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”

“…Large numbers of Pecos bluntnose shiner eggs and larvae, and possibly older individuals as well, are displaced into poor quality habitat by high magnitude and duration deliveries of irrigation water (summarized in USFWS 2006, Hoagstrom et al 2008, and additional information on retention and displacement of Pecos bluntnose shiner eggs and larvae could prove usell for conservation efforts. For example, it may be possible to adjust the timing and magnitude of water deliveries to reduce displacement.…”

—Authors' Response—

“…The intent of the simple egg drift model was to show that final egg distributions are dependent upon both egg retention rates and the source and quantity of eggs released. The mean, adult PBNS distribution, the general accuracy of which is not in question (Hoagstrom et al 2008), adequately demonstrates this.…”

“…However, the source of this variability is uncertain and is likely confounded by sampling error. PBNS catch per effort monitoring has been based on "exploratory" sampling methods (Hoagstrom et al 2008). PBNS are known to be habitat specialists with a non-random distribution ).…”

Drift versus retention: an alternative perspective to Wilde and Urbanczyk's ‘relationship between river fragment length and persistence of two imperiled great plains cyprinids’

“…Coincidentally, retentive river reaches are highly suitable for adults (Hoagstrom et al 2008a(Hoagstrom et al , 2008b. Thus, spawning occurs where retention is high and young and adults commonly co-occur (Polivka 1999;Hoagstrom et al 2006a;Durham & Wilde 2009a).…”

“…Thus, spawning occurs where retention is high and young and adults commonly co-occur (Polivka 1999;Hoagstrom et al 2006a;Durham & Wilde 2009a). Local retention seems evident where populations persist over time, spawning adults are present, and young-of-year outnumber adults (e.g., Lehtinen & Layzer 1988;Taylor & Miller 1990;Hoagstrom & Brooks 2005;Hoagstrom et al 2008b). Young-of-year that recruit in proximity to adults also have the advantage of ready access to suitable juvenile and adult habitats (e.g., Polivka 1999;Hoagstrom et al 2008a).…”