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Influences On The Instream Distribution Of Astyanax Fasciatus In A Small River In Costa Rica., Cecil Kelly Swing
Influences On The Instream Distribution Of Astyanax Fasciatus In A Small River In Costa Rica., Cecil Kelly Swing
LSU Historical Dissertations and Theses
The instream distribution of the tetra, Astyanax fasciatus, was investigated through approximately 700 hours of field observations in a small Costa Rican stream on the southwestern Pacific coast near Golfito. Individuals tended to remain in particular pools where they subsisted primarily on a diet of terrestrial insects. These fish were able to migrate, and only as many individuals stayed in any pool as could be sustained there by available food resources. Because the water intercepted insects fairly uniformly over its surface, the biomass of fish occupying any particular pool was proportional to its surface area (r$\sp2$ = 0.652). The amount …
Host Quality Of Baldcypress And Its Influence On Fruittree Leafroller, Archips Argyrospila (Walker) (Lepidoptera: Tortricidae), Performance In Forested Wetlands Of Louisiana., James R. Meeker
LSU Historical Dissertations and Theses
Ecological relationships between the fruittree leafroller (FTLR), (Archips argyrospila (Walker)) and a new host, baldcypress (Taxodium distichum (L.)), were investigated in southern Louisiana where persistent annual defoliation over increasingly larger areas has occurred since 1983. Defoliation was observed to correspond with common types of baldcypress foliage morphology; designated as open and appressed. Pondcypress, Shumard oak and citrus foliage also were examined. The objectives were to: (1) determine the relative suitability/susceptibility of foliage types, and (2) quantify parameters of foliage quality possibly influencing FTLR performance. Levels of defoliation, egg mass counts, and laboratory bioassays of: initial survival, host preference, growth, feeding, …
Ecosystem Models Of Aquatic Primary Production And Fish Migration In Laguna De Terminos, Mexico., Enrique Reyes
Ecosystem Models Of Aquatic Primary Production And Fish Migration In Laguna De Terminos, Mexico., Enrique Reyes
LSU Historical Dissertations and Theses
Laguna de Terminos is Mexico's largest coastal lagoon. There is a high habitat diversity including open water, mangroves, seagrasses and marshes, which supports Mexico's most economically important fisheries. Understanding ecosystem processes is essential for effective management of the lagoon's resources. This research developed landscape-level models for aquatic primary production (LAPPTER model), and fish migration (ROE model) in Laguna de Terminos. The ROE model was developed first as a theoretical approach, and later integrated into the LAPPTER model as a submodule which utilizes simulated production as a food source. The ROE model includes behavioral rules for fish movement based on environmental …