The Evolutionary Effects of Fishing: Implications for Stock Management and Rebuilding

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dc.contributor.authorLeaf, Robert Thomasen
dc.contributor.committeechairJiao, Yanen
dc.contributor.committeememberHallerman, Eric M.en
dc.contributor.committeememberMurphy, Brian R.en
dc.contributor.committeememberBerkson, James M.en
dc.contributor.committeememberPrager, Michael H.en
dc.contributor.departmentFisheries and Wildlife Sciencesen
dc.date.accessioned2014-03-14T20:15:07Zen
dc.date.adate2010-08-25en
dc.date.available2014-03-14T20:15:07Zen
dc.date.issued2010-06-22en
dc.date.rdate2010-08-25en
dc.date.sdate2010-08-12en
dc.description.abstractRecent empirical studies have demonstrated inter-generational morphological and life-history changes in fish stocks that have been impacted by size-selective harvest. Evolutionary processes in biological populations occur through differential survival and reproductive success based, in part, upon individual phenotypic variability. Fishing is a source of directional selection resulting in the directed removal of some phenotypes; however, many aspects of the evolutionary effects of fishing remain have yet to be described. In order to better understand the life-history and morphological changes that occur as a result of size-selective fishing, and their effect on fishery dynamics, I first determined the suitability of Japanese medaka (Oryzias latipes) for selection experiments. I performed selection experiments using Japanese medaka and report how morphology and life-history characteristics changed over multiple generations of selection. I then used these patterns of change in life-history and morphology to validate individual-based simulation candidate models to test general mechanisms of life-history relationships. Finally, I applied the individual-based simulation modeling approach in order to describe how biological and fishery characteristics change in a large, age-structured population exposed to size-selective fishing over multiple generations. I found that the Japanese medaka has attractive characteristics for biological investigation. The selection experiments indicated large changes in the age-atmaturity, including a nearly 50% decrease over four generations in the most intense sizeselective removal regimes. However, I did not observe significant changes in length-at-age or weight-at-age over the course of the experiment. Candidate simulation models were poor at predicting some aspects of the life-history characteristics of Japanese medaka. The simulation model to determine fishery characteristics predicted large decreases in yield and egg production as a result of decreases in length-at-age. Understanding the relationships of life-history characteristics and their role in determining population resilience is a step toward understanding the importance of evolutionary processes in fishery management.en
dc.description.degreePh. D.en
dc.identifier.otheretd-08122010-063252en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08122010-063252/en
dc.identifier.urihttp://hdl.handle.net/10919/28636en
dc.publisherVirginia Techen
dc.relation.haspartLEAF_Dissertation_2010.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectJapanese medakaen
dc.subjectOryzias latipesen
dc.subjectaquacultureen
dc.subjectlife-history evolutionen
dc.subjectquantitative geneticsen
dc.subjectheritabilityen
dc.subjectindividual-based modelen
dc.subjectfishery-induced evolutionen
dc.titleThe Evolutionary Effects of Fishing: Implications for Stock Management and Rebuildingen
dc.typeDissertationen
thesis.degree.disciplineFisheries and Wildlife Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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