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dc.contributor.advisorTash, Jerryen_US
dc.contributor.authorMCMAHON, THOMAS ELWOOD.
dc.creatorMCMAHON, THOMAS ELWOOD.en_US
dc.date.accessioned2011-10-31T18:52:26Z
dc.date.available2011-10-31T18:52:26Z
dc.date.issued1984en_US
dc.identifier.urihttp://hdl.handle.net/10150/187817
dc.description.abstractThe hypothesis that emigration of individuals in excess of resource carrying capacity acts as a population regulatory mechanism was tested experimentally using the desert pupfish (Cyprinodon macularius). When emigration was prevented, four pupfish populations monitored from May 1982 to March 1984 were unable to regulate numbers to resources. Numbers increased to a mean peak size 1.4 times greater than four pools open to emigration, followed by high mortality, a decline in body condition, reduced recruitment, and stunting. The pattern of overpopulation was similar to that observed in fenced populations of rodents. In contrast, pupfish in open pools had lower numbers, higher recruitment, better condition and growth, and higher total production. Emigration patterns were similar in all four open pools. Population size, rate of increase, and temperature affected emigration rates. Nearly twice as many males than females emigrated. Emigrant pupfish usually had poorer condition factors than residents. Pupfish showed a rapid and uniform increase in emigration when resources were reduced. Nearly one-half (42.2 and 41.8%) of pupfish populations emigrated from two open pools wherein resources were suddenly reduced by 50%. Many fewer fish emigrated from undisturbed control pools (15.2 and 16.0%). The results suggest that residency-emigratory behavior of pupfish can reliably and precisely effect changes in numbers to be in consonance with resources. They support emigration as sufficient to regulate pupfish numbers to resources in open systems without the need for other factors or mechanisms.
dc.language.isoenen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectDesert pupfish -- Arizona.en_US
dc.subjectFishes -- Migration -- Arizona.en_US
dc.titleTHE ROLE OF EMIGRATION IN THE DYNAMICS AND REGULATION OF POPULATIONS OF THE DESERT PUPFISH (CYPRINODON MACULARIUS).en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc693324955en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberMatter, Williamen_US
dc.contributor.committeememberShaw, Williamen_US
dc.contributor.committeememberSowls, Lyleen_US
dc.contributor.committeememberZiebell, Chucken_US
dc.identifier.proquest8501917en_US
thesis.degree.disciplineRenewable Natural Resourcesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-09-03T14:58:57Z
html.description.abstractThe hypothesis that emigration of individuals in excess of resource carrying capacity acts as a population regulatory mechanism was tested experimentally using the desert pupfish (Cyprinodon macularius). When emigration was prevented, four pupfish populations monitored from May 1982 to March 1984 were unable to regulate numbers to resources. Numbers increased to a mean peak size 1.4 times greater than four pools open to emigration, followed by high mortality, a decline in body condition, reduced recruitment, and stunting. The pattern of overpopulation was similar to that observed in fenced populations of rodents. In contrast, pupfish in open pools had lower numbers, higher recruitment, better condition and growth, and higher total production. Emigration patterns were similar in all four open pools. Population size, rate of increase, and temperature affected emigration rates. Nearly twice as many males than females emigrated. Emigrant pupfish usually had poorer condition factors than residents. Pupfish showed a rapid and uniform increase in emigration when resources were reduced. Nearly one-half (42.2 and 41.8%) of pupfish populations emigrated from two open pools wherein resources were suddenly reduced by 50%. Many fewer fish emigrated from undisturbed control pools (15.2 and 16.0%). The results suggest that residency-emigratory behavior of pupfish can reliably and precisely effect changes in numbers to be in consonance with resources. They support emigration as sufficient to regulate pupfish numbers to resources in open systems without the need for other factors or mechanisms.


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