Thesis--University of Michigan. / Reprinted from Ecological monographs, 18 ... January, 1948. Literature cited: p. 41-43.

Thesis (M.A.)--University of North Carolina Wilmington, 2008. / Title from PDF title page (viewed September 22, 2008 ) Includes bibliographical references ( p. 41-44)

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: William Howell, Coral Lamartiniere, R. Douglas Watson, Stephen A. Watts. Description based on contents viewed Feb. 7, 2008; title from title screen. Includes bibliographical references.

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on June 29, 2010). Bibliography: leaves 21-25.

No description available.

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on Aug. 19, 2009). Bibliography: leaves 37-41.

In experimental pools open to emigration, mosquitofish (Gambusia affinis) resided at higher densities than topminnow (Poeciliopsis occidentalis). When Gambusia were introduced to Poeciliopsis pools, all topminnow maintained residency. Only 11% of the Gambusia emigrated from the mixed populations before the plant cover was removed; with no cover, 59% left. A significant number of Gambusia in single species pools also responded to a loss of cover by emigrating. Continuing residency of Poeciliopsis after introduction of Gambusia supports findings that displacement by mosquitofish is not an immediate process. Frayed fins on resident topminnow suggest short-term agonistic interactions. Coexistence of an exotic species (Gambusia) and an endangered desert fish (Poeciliopsis) may depend on the complexity, or spatial variation, of the Southwest's few remaining cienegas. The opportunity to disperse from pools in these habitats may be an important factor in Poeciliopsis survival; such emigratory behavior can be tested in open experimental systems.

No description available.

The introduction of pharmaceuticals and personal care products (PPCPs) to aquatic systems has impacted development and reproductive health of fish in many regions of the world. This study investigated western mosquitofish in the bayou systems of Harris County, Texas for evidence of morphological and reproductive abnormalities. Mosquitofish were sampled above and below WWTPs on five streams during May and August 2010, and specimens were dissected and analyzed for reproductive (egg/embryo weight, embryo/egg number and embryos staging), morphological (liver and gonad weight, body length, gonadosomatic index and hepatosomatic index) and histological indicator variables. In addition, water samples were analyzed for concentrations of PPCPs. Spatial and temporal variation was observed among all indicator variables, however no consistent differences were found above versus below WWTP discharges. Histopathology showed no evidence of lesions or presence of intersex individuals. Chemical analysis revealed a variety of pharmaceuticals and anthropogenic chemicals present in the Houston area waterways, however all were at concentrations lower than those known to cause impacts to fishes. These results suggest that the current concentrations of chemicals being discharged from WWTPs into headwater reaches of streams in the suburban area of west Houston are below levels that impact the physiology of male and female mosquitofish.

Mosquitofish (Gambusia holbrooki) are native to the southeastern United States but invasive elsewhere, and are dominant predators in many ecosystems that they inhabit. Information on dispersal behavior will help better understand and predict mosquitofish metapopulation dynamics and invasions. I experimentally tested dispersal behavior of individual mosquitofish under a range of laboratory conditions relevant to field situations. Preliminary experiments showed that gender, lighting conditions, hunger and acclimation time did not significantly affect net dispersal rate. Power analysis based on this preliminary experiment determined that 6 replicate fish were sufficient for each subsequent experiment; I used 24 fish, and each fish was tested one time. Three factors that potentially could affect net swimming rate were tested: habitat of origin (permanent vs. temporary waters), water depth (3-24 mm), and the interaction between water depth and leaf litter type (upland and wetland). Fish from a temporary pond dispersed significantly faster than fish from a permanent pond, and fish dispersed significantly faster in deeper water than in shallower water. However, leaf litter significantly inhibited fish dispersal at all depths tested. Based on these experiments, G. holbrooki disperse more readily through relatively open and deeper (several centimeters) pathways between habitats such as roadside ditches, drainage canals and trails in flooded conditions. My results are useful for understanding mosquitofish dispersal behavior based on the abiotic and biotic factors examined in this experiment. I predict that mosquitofish can spread from a point of introduction at about 800 m per day, given and unobstructed path of only > 6 mm depth.