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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 …
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 …
Systematics, Redescription, And Geographic Variation Of The Blackside Darter, Percina Maculata (Pisces; Percidae)., Eugene Clifton Beckham Iii
Systematics, Redescription, And Geographic Variation Of The Blackside Darter, Percina Maculata (Pisces; Percidae)., Eugene Clifton Beckham Iii
LSU Historical Dissertations and Theses
A systematic study of the North American percid fish Percina (Alvordius) maculata (Girard) was undertaken to determine the extent and pattern of geographic variation, subspeciation, and sexual dimorphism. A brief nomenclatorial history is presented, the species is redescribed, and variation, distribution, habitat, and subgeneric relationships are discussed. Other than dorsal fin pigmentation, absence of modified midventral scales in females, and limited intrapopulational sexual dimorphism in a few morphometric characters, no variation in most of the thirty-nine characters examined is present between males and females. Morphometrics exhibited no pattern of geographic variation; however, meristic characters revealed a major trend in geographic …