Monitoring of adult Lost River and shortnose suckers in Clear Lake Reservoir, California, 2008–2010

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Suggested citation: Hewitt, D.A., and Hayes, B.S., 2013, Monitoring of adult Lost River and shortnose suckers in Clear Lake Reservoir, California, 2008: U.S. Geological Survey Open-File Report 2013-1301. ISSN 2331ISSN -1258 Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. Tables Table 1. Catches of Lost River and shortnose suckers in fall trammel net sampling in Clear Lake Reservoir, California, 2006-2009 Trammel net sampling resulted in a relatively low catch of suckers in fall 2008 and a high catch of suckers in fall 2009. We attribute the high catch of suckers to low lake levels in 2009, which concentrated fish. As in previous years, shortnose suckers made up the vast majority of the sucker catch and recaptures of previously PIT-tagged suckers were relatively uncommon. Across the 2 years, we captured and tagged 389 new Lost River suckers and 2,874 new shortnose suckers. Since the program began, we have tagged a total of about 1,200 Lost River suckers and 5,900 shortnose suckers that can be detected on the remote antennas in Willow Creek. Detections of tagged suckers were low in both spring 2009 and spring 2010. The magnitude of the spawning migration was presumably small in both years because of low flows in Willow Creek; detections were similar to a previous low-flow year (spring 2007) and much lower than previous years with higher flows (spring 2006 and spring 2008).The size composition of fish captured in fall trammel net sampling over time suggests that the Lost River sucker population probably has decreased in abundance from what it was in the early 2000s. Shortnose suckers are smaller than Lost River suckers, and we are unable to infer any trend in abundance for shortnose suckers because it is impossible to separate recruitment of small fish from size selectivity of the trammel nets. Nonetheless, the substantial catch of small shortnose suckers in 2009, especially females, indicates that some new individuals recruited to the population.Problems with inferring status and population dynamics from size composition data can be overcome by a robust capture-recapture program that follows the histories of PIT-tagged individuals. Inferences from such a program are currently hindered by poor detection rates during spawning seasons with low flows in Willow Creek, which indicate that a key assumption of capture-recapture models is violated. We suggest that the m...

Colonial Waterbird Predation on Lost River and Shortnose Suckers in the Upper Klamath Basin

“…Adult Lost River and Shortnose suckers in Clear Lake were captured using trammel nets similar to those used in Upper Klamath Lake. Suckers in Clear Lake were primarily captured in the west lobe during September and October (Hewitt and Hayes 2013). Nets were set at various locations, but effort was concentrated near the shoreline where catches were consistently the highest.…”

“…Samples of Lost River and Shortnose suckers are tagged each year with PIT tags to gather information on their behavior and survival following release (Janney et al 2008;Hewitt and Hayes 2013;Burdick et al 2015;Hewitt et al 2015). The PIT tags allow specific information to be linked to individual fish, such as species, size, age-class (adult, juvenile), and release location.…”

Juvenile sucker cohort tracking data summary and assessment of monitoring program, 2015

“…Both species are lake dwelling catostomids that make springtime migrations from about 4 to 7 years of age to lake shore or tributaries spawning areas (Hewitt and others, 2015). Upper Klamath Lake populations typically spawn from March to June, whereas Clear Lake Reservoir populations spawn from February to April (Hewitt and Hayes, 2013;Burdick, Hewitt, and others, 2015;Hewitt and others, 2015). Larvae of Upper Klamath Lake river spawning populations outmigrate at night in May and early June to in-lake rearing habitats within several days of emerging from gravel (Cooperman and Markle, 2003).…”

“…Uncertainty exists regarding if Clear Lake Reservoir populations are similarly recruitment limited, because recruitment in Clear Lake Reservoir is intermittent but not infrequent (Hewitt and Hayes, 2013). In Upper Klamath Lake, decreasing catch rates of age-0 juvenile suckers during August and September in most years and a lack of age-1 or older juvenile sucker catches indicate that the lack of recruitment is due to high mortality within the first year of life (Burdick and VanderKooi, 2010).…”

Demographics and run timing of adult Lost River (<i>Deltistes luxatus</i>) and short nose (<i>Chasmistes brevirostris</i>) suckers in Upper Klamath Lake, Oregon, 2012

“…Smaller fish that could be considered new recruits have not made up a substantial part of the catch in any year in the last decade. Sampling with the same trammel nets in the past in Upper Klamath Lake (Janney and others, 2008), as well as in Clear Lake Reservoir, California where recruitment of new spawners has occurred (Hewitt and Hayes, 2013), showed that the nets captured fish as small as 300 mm FL. Thus, trammel net selectivity cannot explain the lack of smaller fish in the recent catches in Upper Klamath Lake.…”