Temporal and spatial distribution of endangered juvenile Lost River and shortnose suckers in relation to environmental variables in Upper Klamath Lake, Oregon: 2009 annual data summary

Abstract

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Inter-annual variability in apparent relative production, survival, and growth of juvenile Lost River and shortnose suckers in Upper Klamath Lake, Oregon, 2001–15

“…Instead, juvenile suckers captured in Upper Klamath Lake were progressively larger from June to September throughout Upper Klamath Lake and CPUEs decreased in all parts of the lake simultaneously others, 2007a, 2007b;Bottcher and Burdick, 2010). Extensive studies of juvenile sucker distribution indicated that age-0 suckers are habitat generalists in Upper Klamath Lake once they reach about 45 mm SL and, therefore, indicated that mid-to late-summer decreases in CPUEs were not due to fish changing habitats (VanderKooi and others, 2004;others, 2007a, 2007b;Bottcher and Burdick, 2010;Burdick and Hewitt, 2012). Furthermore, age-0 to age-6 Lost River and shortnose suckers have been captured in Clear Lake Reservoir with the same gear as used in Upper Klamath Lake, indicating that gear avoidance cannot completely explain the nearcomplete annual disappearance of juvenile suckers from Upper Klamath Lake (Burdick and others, 2015).…”

“…Sampling of suckers throughout Upper Klamath Lake, in the lake's tributaries, and near the lake outlet indicate that emigration and reduced susceptibility to gear alone cannot explain the near absence of older juvenile suckers others, 2007a, 2007b;Bottcher and Burdick, 2010). Summertime movement of juvenile suckers along the eastern shore and toward the lake outlet was not detected from July to September during 2002-06 (Hendrixson and others, 2007a), nor was there a shift in abundance of age-0 juvenile suckers from northern and eastern parts of the lake near spawning areas to areas near lake outlets in lakewide sampling from June to September during 2007-09 (Bottcher and Burdick, 2010).…”

“…Summertime movement of juvenile suckers along the eastern shore and toward the lake outlet was not detected from July to September during 2002-06 (Hendrixson and others, 2007a), nor was there a shift in abundance of age-0 juvenile suckers from northern and eastern parts of the lake near spawning areas to areas near lake outlets in lakewide sampling from June to September during 2007-09 (Bottcher and Burdick, 2010). Instead, juvenile suckers captured in Upper Klamath Lake were progressively larger from June to September throughout Upper Klamath Lake and CPUEs decreased in all parts of the lake simultaneously others, 2007a, 2007b;Bottcher and Burdick, 2010).…”

“…Summertime movement of juvenile suckers along the eastern shore and toward the lake outlet was not detected from July to September during 2002-06 (Hendrixson and others, 2007a), nor was there a shift in abundance of age-0 juvenile suckers from northern and eastern parts of the lake near spawning areas to areas near lake outlets in lakewide sampling from June to September during 2007-09 (Bottcher and Burdick, 2010). Instead, juvenile suckers captured in Upper Klamath Lake were progressively larger from June to September throughout Upper Klamath Lake and CPUEs decreased in all parts of the lake simultaneously others, 2007a, 2007b;Bottcher and Burdick, 2010). Extensive studies of juvenile sucker distribution indicated that age-0 suckers are habitat generalists in Upper Klamath Lake once they reach about 45 mm SL and, therefore, indicated that mid-to late-summer decreases in CPUEs were not due to fish changing habitats (VanderKooi and others, 2004;others, 2007a, 2007b;Bottcher and Burdick, 2010;Burdick and Hewitt, 2012).…”

“…Catch per unit effort, length, age, and species identification data for juvenile suckers were collected as part of habitat use and sucker health research by the U.S. Geological Survey (USGS) from 2001 to 2015 in Upper Klamath Lake. These data previously were analyzed to understand habitat use, sucker distribution, and migration patterns (VanderKooi and Buelow, 2001;VanderKooi and others, 2004;Burdick and others, 2007;others, 2007a, 2007b;others, 2009a, 2009b;Bottcher and Burdick, 2010;Burdick and Brown, 2010;Burdick and VanderKooi, 2010;Burdick, 2012aBurdick, , 2012bBurdick and Hewitt, 2012;Burdick, 2013;Burdick and others 2015). We examined trends in these data to describe annual variability in sucker dynamics that in future research may be correlated with environmental conditions to better assess the reasons for the failure of suckers to thrive in Upper Klamath Lake.…”