Predation on larval suckers in the Williamson River Delta revealed by molecular genetic assays—A pilot study

Open-File Report 2016-1094
By: , and 

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Abstract

Predation of endangered Lost River suckers (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) during larval egress to Upper Klamath Lake from the Williamson River is poorly understood but may be an important factor limiting recruitment into adult spawning populations. Native and non-native piscivores are abundant in nursery wetland habitat, but larval predation has not been directly studied for all species. Larvae lack hard body structures and digest rapidly in predator digestive systems. Therefore, traditional visual methods for diet analysis may fail to identify the extent of predation on larvae. The goals of this study were to (1) use quantitative polymerase chain reaction (qPCR) and single nucleotide polymorphism (SNP) assays developed for Lost River and shortnose suckers to assay predator stomach contents for sucker DNA, and (2) to assess our ability to use this technique to study predation. Predators were captured opportunistically during larval sucker egress. Concurrent feeding trials indicate that most predators—yellow perch (Perca flaverscens), fathead minnow (Pimephales promelas), blue chub (Gila coerulea), Klamath tui chub (Siphatales bicolor bicolor), Klamath Lake sculpin (Cottus princeps), slender sculpin (Cottus tenuis)—preyed on sucker larvae in the laboratory. However, sucker DNA was not detected in fathead minnow stomachs. Of the stomachs screened from fish captured in the Williamson River Delta, 15.6 percent of yellow perch contained sucker DNA. This study has demonstrated that the application of qPCR and SNP assays is effective for studying predation on larval suckers. We suggest that techniques associated with dissection or detection of sucker DNA from fathead minnow stomachs need improvement.

Suggested Citation

Hereford, D.M., Ostberg, C.O., and Burdick, S.M., 2016, Predation on larval suckers in the Williamson River Delta revealed by molecular genetic assays—A pilot study: U.S. Geological Survey Open-File Report 2016-1094, 16 p., http://dx.doi.org/10.3133/ofr20161094.

ISSN: 2331-1258 (online)

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Table of Contents

  • Abstract
  • Introduction
  • Methods
  • Results
  • Discussion
  • Acknowledgments
  • References Cited

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Predation on larval suckers in the Williamson River Delta revealed by molecular genetic assays—A pilot study
Series title Open-File Report
Series number 2016-1094
DOI 10.3133/ofr20161094
Year Published 2016
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Western Fisheries Research Center
Description iv, 16 p.
Country United States
State Oregon
Other Geospatial Williamson River Delta
Online Only (Y/N) Y
Additional Online Files (Y/N) N