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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Environment-induced Phenotypic Plasticity in the Teeth of Hatchery and Wild Largemouth Bass, <i>Micropterus floridanus</i>

Selvaraj, Tamilselvi 01 August 2010 (has links)
Successful stock enhancement of hatchery-reared fish depends heavily on the release of individuals able to demonstrate strong survival skills. Overall survival of fishes is a reflection of a successful blend of physiology, anatomy, and behavior. With fishes being highly phenotypically plastic, the potential exists for all aspects of hatcheryreared fish to vary significantly from their wild counterparts while having potentially adverse effects on their survival after release. Previous analyses have demonstrated significant differences between the feeding behavior of hatchery-reared and wild caught largemouth bass (Micropterus floridanus) in the laboratory, as well as differences in the development of the skull between these two groups. The aim of this study was to determine if oral and pharyngeal jaw dentition differed between hatchery and wild bass. Scanning electron micrographs of the oral and pharyngeal jaws from an overlapping size range of 30 hatchery-reared and 30 wild bass were compared for the number and characteristics of oral and pharyngeal teeth. Wild bass were found to have features which would presumably allow more efficient capture of prey. The results of the study suggested that wild bass exhibited greater number of teeth when compared to hatchery reared bass. They also exhibited oral and pharyngeal teeth which were greater in length, and pharyngeal teeth that were greater in width when compared to hatchery-reared bass. This deficiency in dentition could have a significant effect on prey-capture success when introduced into the wild. We suggest that exposure to wild prey during the grow-out phase of aquaculture could provide the necessary adaptive plasticity of hatchery-reared bass dentition

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