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Origins and movements of invasive piscivores determined from otolith isotopic markers

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dc.contributor.authorWolff, Brian, author
dc.contributor.authorJohnson, Brett, advisor
dc.contributor.authorClements, William, committee member
dc.contributor.authorSanford, William, committee member
dc.date.accessioned2007-01-03T05:34:28Z
dc.date.available2007-01-03T05:34:28Z
dc.date.issued2011
dc.description.abstractI examined the utility of the strontium isotope (87Sr/86Sr) ratio in fish otoliths to determine the origins and movements of invasive piscivores in the Upper Colorado River Basin (UCRB). My goal was to determine if invasive piscivores entered riverine habitat of endangered fishes in the UCRB by escaping from reservoirs, and if so, determine their likely origins. Fishes were collected from 14 reservoirs and rivers directly downstream. My objectives were to examine the distinctiveness of 87Sr/86Sr ratios from fishes in different reservoirs, and temporal stability and interspecies variability of 87Sr/86Sr ratios of fishes within reservoirs. Variance components analysis and model selection using an information theoretic approach were used to rank relative importance of reservoir location, species and year on 87Sr/86Sr ratios. My results showed that in most cases 87Sr/86Sr ratios were unique across reservoirs, overlapped among species in a given reservoir, and were temporally stable across years. I was able to identify the likely reservoir of origin of river-caught fish, and I was able to determine, in some cases, the year of escapement. Overall, my results demonstrate the utility of 87Sr/86Sr ratios for tracking fish movement and origin in river-reservoir systems and provide important insights into processes that affect escapement risk such as dam operations, weather conditions, fish behavior and fish physiology. Analysis of stable isotopes hydrogen (δ2H), carbon (δ13C), and oxygen (δ18O) were performed on a sub-set of otoliths from the 87Sr/86Sr ratio analysis to determine if additional markers aid in discriminating between groups, particularly when 87Sr/86Sr ratios are similar among different locations. A canonical discriminant function analysis was used to visually differentiate different locations using natural isotopes. These results showed that δ13C and δ18O provide very useful separation among different groups, particularly when in conjunction with 87Sr/86Sr ratios.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierWolff_colostate_0053N_10534.pdf
dc.identifier.urihttp://hdl.handle.net/10217/48145
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectColorado River
dc.subjectisotope
dc.subjectotolith
dc.subjectpiscivore
dc.subjectreservoir
dc.subjectstrontium
dc.titleOrigins and movements of invasive piscivores determined from otolith isotopic markers
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineFish, Wildlife, and Conservation Biology
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)

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