Näytä suppeat kuvailutiedot

dc.contributor.authorKopra, Juho
dc.date.accessioned2014-01-16T19:11:36Z
dc.date.available2014-01-16T19:11:36Z
dc.date.issued2013
dc.identifier.otheroai:jykdok.linneanet.fi:1291207
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/42811
dc.description.abstractIn this work, the aim was to produce a realistic assessment of yearly mortality of Archipelago Sea pike perch during the period 1997-2012. The utilized data origins from the mark-recapture experiment carried out by the Finnish Game and Fisheries Research Institute (FGFRI). In this mark-recapture experiment, returnings of the marks were based on voluntary tag reporting by the fishermen gaining small monetary rewards. In this study design, the count of returned tags is affected by the size of the release cohort, efficiency of the fishing method used by a fisherman and the fisherman’s willingness to return the tag. In addition, each year a proportion of the tags become detached from fish, which means that those tags cannot be returned. All these factors were taken into account in a hierarchical model, which was developed in the same fashion as the well-known Cormack-Jolly-Seber model. Data from the yearly total catch were not used in this work because those data will be used in the subsequent research utilizing results of this work. The objective of this work was to estimate fishing gear specific catchability coefficients and mortality rates, including natural mortality rate. The amount of data and number of parameters to be estimated set their own limitations, so it was decided to estimate parameters of interest by splitting the data into only three fishing fleets: professional fishermen, recreational net fishermen and recreational line fishermen. The estimability of the hierarchical model developed for mark-recapture data was studied using simulation experiments. One was able to find such a model configuration, where the parameters concerning mortality estimates may be es- timated without significant systematic errors in the estimated posterior distri- butions. Simultaneously, the tag reporting probabilities were estimated for each of the three fishing fleets although systematic errors remained for these param- eters. The final mortality estimate indicates that about half of the Archipelago Sea pike perch population is removed annually. For the recent years about half of this mortality was caused by professional fishing, and almost the same amount was due to natural death. The mortality caused by recreational fishing is the smallest mortality component. The estimate concerns population similar to released cohorts. The produced estimate is sensitive to many factors, whereas effects of environmental change, or changes in seal or cormorant abundances, were beyond the scope of this work.en
dc.format.extent1 verkkoaineisto (52 sivua)
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.rightsThis publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.en
dc.rightsJulkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.fi
dc.subject.otherBayes
dc.subject.otherkuha
dc.subject.otherkuolleisuus
dc.subject.othermerkintä-takaisinpyynti
dc.titleUtilising mark-recapture data for Bayesian modelling of fish mortality
dc.identifier.urnURN:NBN:fi:jyu-201401161075
dc.type.ontasotPro gradu -tutkielmafi
dc.type.ontasotMaster’s thesisen
dc.contributor.tiedekuntaMatemaattis-luonnontieteellinen tiedekuntafi
dc.contributor.tiedekuntaFaculty of Sciencesen
dc.contributor.laitosMatematiikan ja tilastotieteen laitosfi
dc.contributor.laitosDepartment of Mathematics and Statisticsen
dc.contributor.yliopistoUniversity of Jyväskyläen
dc.contributor.yliopistoJyväskylän yliopistofi
dc.contributor.oppiaineTilastotiedefi
dc.contributor.oppiaineStatisticsen
dc.date.updated2014-01-16T19:11:37Z
dc.rights.accesslevelopenAccessfi
dc.type.publicationmasterThesis
dc.contributor.oppiainekoodi4043
dc.subject.ysobayesilainen menetelmä
dc.subject.ysokuha
dc.subject.ysokuolleisuus
dc.format.contentfulltext
dc.type.okmG2


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