Revised; Originally Published: 2006 / 2 pp.

The ability of an organism to disperse to suitable habitats, especially in modified and fragmented systems, determines individual fitness and overall population viability. The bluehead sucker (Catostomus discobolus), flannelmouth sucker (Catostomus latipinnis), and roundtail chub (Gila robusta) are three species native to the upper Colorado River Basin that now occupy only 50% of their historic range. Despite these distributional declines, populations of all three species are present in the San Rafael River, a highly regulated tributary of the Green River, Utah, providing an opportunity for research. Our goal was to determine the timing and extent of movement, habitat preferences, and limiting factors, ultimately to guide effective management and recovery of these three species. In 2007-2008, we sampled fish from 25 systematically selected, 300-m reaches in the lower 64 km of the San Rafael River, spaced to capture the range of species, life-stages, and habitat conditions present. We implanted all target species with a passive integrated transponder (PIT) tag, installed a passive PIT tag antennae, and measured key habitat parameters throughout each reach and at the site of native fish capture. We used random forest modeling to identify and rank the most important abiotic and biotic predictor variables, and reveal potential limiting factors in the San Rafael River. While flannelmouth sucker were relatively evenly distributed within our study area, highest densities of roundtail chub and bluehead sucker occurred in isolated, upstream reaches characterized by complex habitat. In addition, our movement and length-frequency data indicate downstream drift of age-0 roundtail chub, and active upstream movement of adult flannelmouth sucker, both from source populations, providing the lower San Rafael River with colonists. Our random forest analysis highlights the importance of pools, riffles, and distance-to-source populations, suggesting that bluehead sucker and roundtail chub are habitat limited in the lower San Rafael River. These results suggest management efforts should focus on diversifying habitat, maintaining in-stream flow, and removing barriers to movement.

For three consecutive years, I monitored the spring stream residency and spawning of five species of fishes using a tributary stream of the Gouin Reservoir (north central Quebec). Timing of spawning of the distantly related species was different whereas the spawning activity of the closely related suckers overlapped in time and space. Intra- and inter-specific egg predation by the two sucker species was observed as well as predation by lake whitefish (Coregonus clupeaformis) on sucker eggs. Synchronisation of the spawning of the suckers may allow them to "swamp" egg predators with drifting eggs. Abundance of spawning fish was affected by water management practices in the reservoir. When water levels were low, fewer fish of all species had access to the stream possibly because of the development of rapids. / The courtship behavior of the two sucker species was described and compared in the same period, to determine if behavioral isolating mechanisms which prevented hybridization existed.

In 2004, a population of dwarf longnose sucker was discovered co-existing with the normal form within the Elk River Watershed of south-eastern British Columbia. This thesis evaluated morphological, genetic and life history characteristics of this dwarf longnose sucker form to determine whether the dwarf morphotype warranted designation as an evolutionary significant unit and to determine any special habitat requirements. In addition to size, distinct morphological differences were indicated between Elk River Watershed dwarf and normal adult longnose sucker, with dwarf adults appearing to retain morphological features of juveniles and sharing morphological features with Salish sucker, which is a separate dwarf longnose sucker form that is considered endangered. Slight, but significant, genetic differences were indicated between Elk River Watershed dwarf and normal longnose sucker forms, and compared to Salish sucker, suggesting some basis for separate designation of the dwarf form. Dwarf longnose sucker are widespread in the Elk River Watershed, and most abundant in small, cool lentic water bodies that contained dense vegetative cover, potential oxycline fluctuation and/or limited fish species diversity. Dwarf adult longnose sucker showed some habitat preference differences compared to normal longnose sucker, with the findings suggesting that dwarf longnose sucker have adopted a more opportunistic life-history strategy than normal longnose sucker. It is postulated that an ontogenetic niche shift has allowed dwarf longnose sucker to more successfully exploit habitats experiencing periodic disturbances (e.g., hypoxia) that, in turn, has led to the occurrence of two longnose sucker morphotypes in the Elk River Watershed.

No description available.

Spatial and temporal variations of Utah Lake’s flow field were modeled using the Estuary Lake and Computer Model from the Centre for Water Research (CWR-ELCOM) at the University of Western Australia as part of an effort to increase understanding of the lake’s natural processes in order to restore the lake to its pristine, clear-water state and preserve the habitat of the June sucker, an endangered species. The model was validated using temperature measurements taken by sensors in 2007. The water temperature was a strong function of air temperature and incident short wave radiation, and was influenced to a lesser degree by wind speed, wind direction, relative humidity, and cloud cover. The water currents were affected most strongly by wind speed and wind direction. The model also predicted the free drifting paths of June sucker larvae entering Utah Lake through the Provo and Spanish Fork Rivers between mid-April and July.

Fish are one of the most imperiled groups of vertebrates worldwide. Threats to fish fall into one of four general categories: physical habitat loss or degradation, chemical pollution, overfishing, and nonnative species introductions. Nonnative predatory fish often have a devastating impact on native prey, especially with endemic fish, whose restricted distribution and often limited evolutionary history with predators make them particularly susceptible to nonnative predators. One reason nonnative fish are often so efficient predators is that the native fish do not recognize the predator as a threat. Although many studies have examined the role of predator odor recognition, no fish have been shown to possess an innate recognition of the odor of predators unless they share a close co-evolutionary history. Many fish learn to identify novel predators through exposure to a predator's odor in conjunction with a conspecific alarm cue. Alarm cues are substances that are stored in the epidermis of many fish and are released when skin cells are broken. Exposure to novel predator odor in conjunction with alarm cue does not necessarily require a fish to survive a close encounter with a predator to be able to learn to recognize the predator. Here I show that it is possible to train hatchery-raised fish (June sucker, Chasmistes liorus) to recognize a nonnative predator odor (largemouth bass, Micropterus salmoides) through exposure to the odor of a predator that has eaten June sucker. I also show that this training can translate into higher survival in subsequent encounters with predators. I propose that training hatchery-raised fish prior to stocking may increase survival of hatchery-raised fish through anti-predator behavior.

Thesis (M.S.)--Utah State University, 1961. / Title from title screen (viewed Aug. 14, 2009). Department: Wildlife Management. Includes bibliographical references. Archival copy available.

This study investigated perceptions of social loafing in undergraduate student teams at a South African university. Student participants, randomly assigned to teams, received coursework instruction about team dynamics (including social loafing) and worked together for 12 weeks on a team assignment that was graded at the end of the semester. Students (n = 243) wrote individual reflections on the reasons for social loafing in student teams. Some (n = 24) also participated in an experiential social loafing exercise. These two sources of qualitative data were used in the development of a survey questionnaire, which was completed by 229 students. Fifty-four percent of the student participants (n = 229) perceived social loafing to have occurred in their teams. Four components of perceived social loafing behaviour were identified using factor analysis: unavailability, poor work quality, tech loafing and discussion non-contribution. Loafer apathy (a general lack of care or interest) predicted significant variance in each of the four loafing behaviours and social compensation. Team performance (assignment grades) was not related to the perceived presence social loafing in a team. Rather than reducing effort in response to perceived social loafing (the sucker effect), a social compensation effect occurred in the perceived presence of poor work quality. Effective leadership moderated the relationship between loafer apathy and tech loafing as well as loafer apathy and social compensation. Practical implications and recommendations for future research are presented.

The spatial scales at which ecological phenomena are viewed constrain the results of interactions between species and their environments. In lake ecosystems, important dynamics have been identified at the landscape scale and the macrohabitat scale. To determine if landscape-scale effects and macrohabitat-scale effects are important in survival and growth of young June suckers, we compared variation among sites in Utah Lake. Large semi-permeable cages were used to house June suckers in situ at five sites representing landscape-scale variation and two sites representing macrohabitat-scale variation in Utah Lake. We compared survival and growth among sites and related it to resource availability (zooplankton abundances), temperature, and disturbance regime to determine if these were possible drivers of variation. Provo Bay had the highest mean survival and high survival in all four cages. Growth differed among sites: Provo Bay and the northwest site had the highest and lowest mean growth rates, respectively. Survival was higher in vegetated water than open water, whereas growth was significantly higher in open water. Zooplankton densities were highest in Provo Bay and the open water habitat, suggesting a positive relationship between food abundance and growth. Temperature patterns were not consistent with differences in growth among sites. Disturbance was greater in the open lake, which may partly explain the higher survival rates in Provo Bay.