Browsing by Subject "fisheries management"
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Item Impacts of Aquatic Vegetation Management on the Ecology of Small Impoundments(2010-01-16) Knight, Trevor J.Aquatic vegetation management and fisheries management are inseparable, however conflicts are often perceived between the two. We investigated the impact of biological, chemical, and no vegetation control on the ecology of private impoundments stocked with largemouth bass and bluegill sunfish. The primary purpose of this study was to determine if aquatic vegetation management had significant impact on pond ecology. A secondary purpose of this study was to collect data for a separate descriptive study on the impact of vegetation management on plankton populations. Nine 0.10 acre ponds were obtained at the Aquaculture Research and Teaching Facility of Texas A and M University in the fall of 2005. Southern naiad (Najas guadalupenis) was transplanted into each pond at a stocking rate of one ton per surface acre. One of three treatments was then randomly assigned to each pond. The treatments were replicated three times and consisted of: an herbicide treatment using Reward and Cutrine, a triploid grass carp treatment, and a control treatment. Fathead minnows (Pimephales promelas), bluegills (Lepomis macrochirus), and largemouth bass (Micropterus salmoides) fingerlings were stocked in each pond. The treatments were initiated on May 31, 2006. Prior to the initiation of the treatments, sampling of each pond occurred for hardness, total phosphorus, nitrite, nitrate, ammonia-nitrogen, dissolved oxygen, turbidity, pH, and temperature. Macroinvertebrate samples were collected from each pond. Post-treatment sampling was conducted on the herbicide treatment and the control at day 2, day 7, day 14, day 28, and monthly thereafter. Posttreatment sampling on the triploid grass carp treatment was conducted at day 14, day 28, and monthly thereafter. One-way ANOVA tests were conducted on the data using SPSS 15.0, and multivariate analysis was conducted using CANOCO software. Significant differences between treatments were found for the parameters turbidity, macrophyte percent coverage, macroinvertebrate species richness, largemouth bass mean weight, and largemouth mean length. Herbicide application and grass scarp stocking significantly decreased the percent coverage of macrophytes in the ponds. Turbidity was significantly increased in the herbicide and grass carp treatments. Largemouth bass mean weight and length were significantly higher in the grass carp ponds. No significant relationships were found in the multivariate analysis; however, there appeared to be several trends within the multivariate analysis that provide insight into potential ecological relationships between the various parameters. The results of this study provide great insight into the impact that various aquatic vegetation management strategies have on the ecology of small impoundments and will help private pond owners and managers conduct better pond management when dealing with aquatic vegetation problems.Item Reducing Uncertainty in Fisheries Management: The Time for Fishers' Ecological Knowledge(2012-07-16) Carr, LiamThis dissertation work presents a novel method for addressing system uncertainty to improve management of a small-scale fishery in St. Croix, United States Virgin Islands. Using fishers' ecological knowledge (FEK), this research examines existing perspectives and biases through the Q-Method to identify regulatory inefficiencies in the management framework and strengthen the rationale for including fishers into the management process, develops a coupled behavior-economics model to predict the likelihood of fishing the preferred grounds under a range of physical and regulatory conditions, establishes a baseline assessment of a spawning aggregation of mutton snapper following sixteen years of protection through a no-take marine protected area, and conducts a discrete choice method test to examine likely public support for FEK-based proposed regulatory alternatives. This work contributes to an under-studied and much-needed area of fisheries management, that of incorporating socioeconomic motivations within an ecosystem-based framework. As fisheries management efforts begin to embrace ecosystem-based approaches, the need for understanding and incorporating the knowledge and behavior of fishers into management has never been greater. Ecological goals of fishery sustainability and continued habitat function cannot be achieved without first understanding how fishers view and respond to any regulatory environment and then developing a framework that achieves the greatest support for those regulations. The time has come for incorporating FEK into ecosystem-based fisheries management.Item Regional and Local-Scale Population Genetic Structure of a Primitive Teleost, the African Bonytongue (Heterotis niloticus), in Rivers of West Africa(2012-10-19) Carrera, ElizabethThe African bonytongue (Heterotis niloticus), one of two living species of the primitive teleost family Arapaimidae, constitutes an important artisanal and commercial fishery in West Africa. This species has also been proposed for wide aquaculture use in Africa. Despite its importance, information on the levels of genetic differentiation for this fish in Benin is lacking, which can contribute to its conservation and management. In this study, regional and local scale genetic differentiation of the African bonytongue in Benin, West Africa, was examined using six microsatellite markers. In total, 221 H. niloticus individuals were sampled from 12 localities in Benin that include three river basins: Oueme-So (ten localities sampled); Mono (one locality); and Niger (one locality). The results showed a high degree of genetic differentiation between African bonytongue samples from the three river basins, which was expected given the barriers for dispersal for aquatic organisms. For the Oueme-So floodplain, they indicate high and homogeneous gene flow, suggesting that seasonal flooding facilitates gene flow across this region. The information obtained from this study will be useful for defining management units for H. niloticus in Benin, and caution against the translocation of individuals from different basins.Item Using Style of Participation among Texas Inshore Fishing Guides to Understand Displacement Behavior due to Perceived Spotted Seatrout (Cynoscion nebulosus) Population Declines(2012-07-16) Smith, WilliamCharacterization of distinct angler fishing styles (e.g., how, where, and with what) allows resource managers the ability to predict how perceived impacts or modifications to fisheries resources (i.e., decline of fish species population) may impact different user groups. Recreation specialization provides a useful framework for understanding participation diversity among recreationists in terms of unique styles of participation. Bryan suggested that within an activity distinct types of participants exist that demonstrate characteristic styles of participation. Fundamental to Bryan's development of specialization were contextual attributes that characterize participant engagement in a recreation activity. However, advancement in specialization has been accompanied by a departure from Bryan's original conceptualization describing activity context. I revisited how specialization is operationalized and developed a contextual style of participation typology and self-classification measure to investigate displacement and substitution behavior among Texas inshore fishing guides. Data were collected in two separate phases. In 2010, I conducted an exploratory investigation that included eighteen face-to-face, in-depth interviews with key informants spanning the entire coast. In 2011, I conducted a quantitative investigation that included mailing a 12 page self-administered survey to all Texas Parks and Wildlife licensed saltwater fishing guides (n=909). Thematic analysis drawing on grounded theory revealed that the salience of six contextual attributes (i.e., bait type, tackle type, fishing method, casting tactic, water depth, and fish species) that characterized four distinct styles of participation (e.g., Bait, All-purpose, Lure, and Sight-casting Guides). A unidimensional self-classification measure was developed based on my guide typology and discriminant analysis revealed it performed as well as a multidimensional measure of specialization. Ultimately, analysis of variance revealed significant differences existed among self-classification categories with respect to substitution behavior (e.g., targeting alternative species of fish, fishing in another location, and using alternative fishing methods or bait types) due to perceived spotted seatrout declines during 2010. In short, my findings suggest that anglers respond differently due to perceived spotted seatrout declines based on their preferred contextual style of participation. A contextual approach to understanding style of participation provides fisheries managers an effective method for understanding and mitigating social and ecological issues.