En masse foraging migrations of Ligia occidentalis Dana were conspicuous events on rocky beaches near Puerto Peñasco, Sonora, Mexico. Experiments were conducted to determine which factors of the environment contained the regulating rhythm for the migration, if indeed the event were cyclic. Experiments were conducted in the laboratory using a tide-simulation aquarium and in the field using mark and release techniques. A time-lapse photography system was used in the field to quantify isopod activity for comparison with environmental factors. A regular cycle for the foraging migration was found. It was in tune with both insolation and tidal cycles so that the isopods began their migrations at the low tides which commenced uncovering the lower intertidal zones during daylight. This resulted in a sudden shift of isopod activity from the evening low tide to the morning low tide when the tides reached spring phase.

There are four distinct subpopulations of loggerhead sea turtles (Caretta caretta) in Florida as determined behaviorally by geographic fidelity, and genetically by mitochondrial haplotypes. The South Florida subpopulation consists of females nesting on the southeastern and southwestern coasts of Florida and their offspring. Previous research shows that west coast hatchlings exhibit higher levels of nocturnal swimming during the postfrenzy period than east coast hatchlings. This study attempted to determine how these differences in migratory behavior develop. A reciprocal translocation experiment was conducted to distinguish between environmental and genetic factors. No consistent differences in hatchling swimming behavior were seen based on geography. Movement of nests resulted in lower levels of nocturnal swimming behavior in hatchlings compared to hatchlings that emerged from natural nests, suggesting that the relocation of nests may not provide a natural incubation environment for developing hatchlings. / by Jeffrey Guertin. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Elasmobranchs (sharks, skates, and rays) migrate across a wide range of spatiotemporal scales, display philopatry, seasonal residency, and maintain home ranges. Many animals use the Earth’s magnetic field to orient and navigate between habitats. The geomagnetic field provides a variety of sensory cues to magnetically sensitive species, which could potentially use the polarity, or intensity and inclination angle of the field, to derive a sense of direction, or location, during migration. Magnetoreception has never been unequivocally demonstrated in any elasmobranch species and the cognitive abilities of these fishes are poorly studied. This project used behavioral conditioning assays that paired magnetic and reinforcement stimuli in order to elicit behavioral responses. The specific goals were to determine if the yellow stingray, Urobatis jamaicensis, could detect magnetic fields, to quantify the nature of the magnetic stimuli it could detect, and to quantify the learning and memory capabilities of this species. The results supported the original hypotheses and demonstrated that the yellow stingray could: discriminate between magnetic and non-magnetic objects; detect and discriminate between changes in geomagnetic field strength and inclination angle; and use geomagnetic field polarity to solve a navigational task. The yellow stingray learned behavioral tasks faster and retained the memories of learned associations longer than any batoid (skate or ray) to date. The data also suggest that this species can classify magnetic field stimuli into categories and learn similar behavioral tasks with increased efficiency, which indicate behavioral flexibility. These data support the idea that cartilaginous fishes use the geomagnetic field as an environmental cue to derive a sense of location and direction during migrations. Future studies should investigate the mechanism, physiological threshold, and sensitivity range of the elasmobranch magnetic sense in order to understand the effects of anthropogenic activities and environmental change on the migratory ability of these fishes. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2001. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 6 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

In December 2019, the Danish government finished building a fence on the border with Germany. Although the fence was nominally intended to prevent wild boar entering Denmark, the government had recently acquired enough barbed wire to reinforce it against human migrants. I tell the story of the wild boar fence in the context of a global trend for escalating border enforcement and environmental change. I explore how border fences shape human and wild animal worlds, drawing on ecological data and using theory from environmental history, border and animal studies. In order to understand how humans and wild animals interact with the German-Danish border fence, I journeyed along it on foot in August 2022. My methodology is autobiographical – by walking the route myself and interviewing local experts and activists in the field, I explored how far humans and wild animals are free to move on the German-Danish border and what habitat fragmentation means for them. Without the ability to move, species worldwide, including humans, could be trapped as regions become uninhabitable due to climate change. A barbed wire border fence on the German-Danish border could prevent people, deer, wolves and other species from adapting to dramatic sea level rise and flooding. I argue that migration is the adaptation, rather than the crisis, and that mobility is something to be protected rather than supressed.