Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed October 15, 2009). PDF text: xiii, 267 p. : maps (some col.) ; 8 Mb. UMI publication number: AAT 3366667. Includes bibliographical references. Also available in microfilm and microfiche formats.

Behaviour and space utilisation of rock-dwelling cichlids were observed at Thumbi East Island, Lake Malawi. 1. Males of five species of the mbuna complex held long-term territories. Pseudotropheus elongatus "aggressive" vigorously defended a feeding area and sometimes a spawning site interspecifically, but did not feed in the peripheral part of their territory. Spawning sites of Pseudotropheus zebra, Pseudotropheus tropheops "orange chest", Labeotropheus fuelleborni, and Petrotilapia nigra were interspecifically-defended, while larger mating territories were defended against conspecific neighbours. Feeding areas were shared with many fish and often extended beyond the defended area. There was considerable variation in behaviour and space use within and between species and between times of day. 2. Non-territorial P. zebra used larger ranges than territorial conspecifics, and fed more on plankton, but individuals had preferred benthic feeding areas, often in conspecific territories. These 'floaters' were often aggressive. Both size and relative brightness independently predicted the outcome of aggressive interactions between floaters, and a site-specific dominance hierarchy was suggested, with some individuals appearing to be semi-territorial. 3. Males and females of 21 and 13 species respectively were found to establish temporary breeding territories. Overall breeding seasonality was bimodal, but reproductive timing and territory characteristics differed among species. Temporary territories had a considerable impact on the behaviour and habitat use of all resident mbuna species, even causing abandonment of territories. 4. Non-breeding Protomelas taeniolatus had limited home ranges, and showed little aggression. During the highly-synchronised reproductive season, males defended spawning sites and females fry-guarding territories. Most chases were directed towards the commonest fish, but predators were chased further and faster. Female behaviour changed over the guarding period. Females generally continued territorial defence after the brood had disappeared. Most broods contained fry of different sizes and species. Significant benefits were found for guarding females with clustered territories, but females did not appear to choose sites adjacent to conspecific parental females. 5. Territoriality in fish is taxonomically widespread and may serve several functions according to species, sex and developmental stage. It also varies according to genotype- and phenotype-limited strategies and short term costs and benefits. Territories may be simultaneously multifunctional.

The north side of Cowichan Lake, Vancouver Island B.C. is underlain by volcanic rocks, sediments, and intrusives of Mesozoic age. The oldest rocks, Jurassic or Triassic flows known as the Sicker andesites, are conformably overlain by about 3000 feet of cherty tuffs, coarser pyroclastics, and small lenses of limestone known as the Sicker sediments. Cherty tuffs form the lower members of the Sicker sediments, felspathic tuffs the central members, and coarser pyroclastics the upper members. About 2000 or 3000 feet of basaltic and andesitic flows conformably overly the Sicker sediments. The Sicker andesites and sediments and younger flows are intruded by large dyke-like bodies of granodiorite or quartz monzonite, known as the Saanich granodlorite and correlated with the Coast Range intrusives. Upper Cretaceous shales sandstones and conglomerate unconformably overlie the volcanics and Intrusives. The Sicker series and overlying flows are tightly folded into overturned and asymmetrical northwesterly trending synclines and anticlines. The Cretaceous rocks are gently folded and dip north along a narrow belt on the north side of a down-faulted block. Manganese deposits occur in the lower cherty beds of the Sicker sediments as lens shaped bodies parallel to the bedding of the sediments. They are commonly in chert free from felspatnic material, and are always associated with jasper or jaspery sediments. The main manganese minerals are rhodonite, spessartite, an unidentified yellow manganese silicate, and small amounts of rhoaochrosite. Residual manganese oxides coat the surfaces of the deposits. Several features of the deposits, such as the fact that rhodonite commonly cross cuts and replaces the chert suggest that the deposits are of replacement origin. Other features such as their bedded appearance and the fact that they occur, at about the same horizon In the Sicker sediments indicate a sedimentary origin. Theoretical considerations support the view that the deposits are sedimentary and suggest that the replacement features were formed by metamorphism. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

In this study, I examined water chemistry of 31 Canadian Shield lakes in relation to catchment characteristics to test the hypothesis that Shield lakes with more marble may exhibit iron (Fe) deficiency and, hence, be more vulnerable to eutrophication. I performed a diatom-based paleolimnological reconstruction of one of these lakes (Heney Lake), which was subjected to anthropogenic stresses including a fish farm. Results suggest that the presence of marble influenced lake chemistry, including lowering the ratio of Fe: P. The reconstruction of historical P concentrations was not statistically possible but past Fe could be inferred, which no previous study has attempted. Certain eutrophication-associated diatom species suggest that logging and European settlement beginning in the early XXth century led to a slight increase in nutrient concentrations. However, a more important diatom species shift was likely related to climate change, as observed in other temperate lakes worldwide.

In the summer of 1964 a study was carried out on the impounded Buttle and Lower Campbell Lakes located on Vancouver Island, British Columbia. An attempt was made to determine the effects of increased water level fluctuation on the limnology, particularly the bottom fauna, in areas with different substrate types. All data from two pre-impoundment studies were examined, and additional sampling carried out to provide a basis for comparison. In addition, several stations were chosen in each lake according to specific substrate types. These different bottom conditions were formed from the combined effects of erosion by water level fluctuation and wave action, over areas where different methods of pre-impoundment clearing of vegetation had been employed. The stations chosen were the shallow onshore areas which were exposed to the air during the winter months of minimum water level, the unexposed area immediately below the minimum drawdown level, and the pre-impoundment littoral zones in each study lake. A single pre-impoundment river channel station was located in Buttle Lake. In addition to bottom dredgings, funnel traps and nocturnal surface tows were used to sample the emerging insect fauna from each station. The total seasonal chironomid catch indicated significantly different total emergence between the several stations sampled. The pre-impoundment river station in Buttle Lake produced the highest total chironomid catch. Among the other stations the unexposed area immediately below the drawdown level was most productive. In Buttle Lake where the greatest seasonal fluctuation occurred and where the completely cleared littoral area was least protected from wave action, the total seasonal emergence over the exposed littoral area was very low. But in Lower Campbell Lake which received a much smaller seasonal water level fluctuation, total emergence was much higher over the exposed littoral. This area was cleared completely in this lake and the irregular shoreline afforded considerable protection from wind action. An inverted bathymetric distribution of the fauna was apparent with the greatest concentration occurring immediately below the drawdown limit in the unexposed littoral zone. The effects of water level changes were therefore considered the most important single factors influencing the bottom fauna distribution in each lake. / Science, Faculty of / Zoology, Department of / Graduate

Understanding the impact which grazers have on their prey is of vital importance in understanding how aquatic ecosystems function. In an attempt to contribute to this understanding, this study examined, at three levels, the effects of zooplankton on phytoplankton biomass in Placid Lake in summer. Examination of selective feeding by the major herbivorous zooplankton species in in situ enclosures revealed that single phytoplankton cells in the range of 6-20 μm long were the preferred food of these organisms. Colonial algae, when dominated by the cyanophyte Merismopedia, did not appear to be grazed. The effect of zooplankton biomass on phytoplankton biomass was examined in in situ enclosures. Generally, phytoplankton biomass decreased only in enclosures where initial zooplankton biomass was very low or very high. A simple model based on the classical logistic model of predator-prey interactions was developed to explain events in the enclosures. I concluded that in summer, Placid Lake phytoplankton depend on nutrients remineralized by zooplankton for growth. Grazing appears to be an important regulating mechanism of the phytoplankton standing crop in the spring but not summer. A third level of study involved examination of the responses of phytoplankton to lake perturbation, namely removal of zooplankton, compared to plankton patterns in previous and subsequent years. In years lacking zooplankton manipulation, major increases in zooplankton biomass in mid spring were followed by phytoplankton biomass increases in late spring. During the first harvesting season, July and August 1979, a 50% reduction in zooplankton biomass was obtained. An enormous bloom of the inedible Merismopedia developed. I hypothesized that removal of zooplankton caused a shortage of available biologically reactive nitrogen which became limiting to eukaryotic phytoplankton, allowing Merismopedia, a blue-green alga which may be able to fix nitrogen, to thrive. In summer, the positive effect of zooplankton on phytoplankton via nutrient remineralization appeared to be more significant than the negative effect of grazing. During the second harvesting season, May, June, and July 1980, no decrease in zooplankton biomass was apparent. Instead of the usual pattern of zooplankton biomass increase preceeding the phytoplankton biomass increase, both increases occurred simultaneously. I concluded that harvesting delayed the rise in zooplankton biomass and decreased the grazing pressure on phytoplankton, allowing it to peak earlier. Grazing may thus be significant in spring in slowing phytoplankton growth. Seasonal variations were introduced to the model for the enclosure experiments to help understand the normal plankton patterns in Placid Lake. The time lag between maximum solar radiation and lake temperature, and the effects of these two physical parameters on phytoplankton and zooplankton growth appear to be instrumental in establishing the pattern of plankton biomass dynamics observed in Placid Lake. / Science, Faculty of / Zoology, Department of / Graduate

The purpose of this thesis is to evaluate whether the Territorial Use-Rights in Fishing (TURFs) of Lake Titieaca, Peru, are effective in overcoming the common property problem of typical fisheries and therefore whether TURFs may prove valuable as part of a more formal management system. It has recently been argued that TURFs should be incorporated into small-scale fisheries management schemes since they should be effective in controlling fishing effort, in promoting a more equitable distribution of the benefits from fishing and in reducing administrative inefficiencies. To determine whether TURFs are in fact effective in controlling fishing effort, I examine Lake Titieaca fisheries in Peru. First, I demonstrate the widespread existence of Lake Titicaca's TURFs and their control over the entire shoreline, most of the littoral area and even part of the pelagic area. Second, I document how, in spite of TURFs' illegality, Lake Titieaca shore dwellers are able to combine legal and illegal means to enforce their traditional rights over their fishing areas. Third, by showing that the relative difference between the returns to labour from fishing with those from alternative activities ranges from 50 to more than 100%, I demonstrate that local fishermen capture substantial fishing rents. If one takes into account that most fishing activities are carried out when there is little else to do, this range increases to 90-180%. I thus conclude that Lake Titieaca fisheries have not reached their bioeconomic equilibrium yet and that the predictions of the common property theory do not apply to them. And fourth, I demonstrate that the origins of these rents can be traced to fishermen's membership in TURF-holding communities, their ability to restrict physical access to the shoreline, and the obligations associated with this membership. Among these obligations are the participation in communal projects and celebrations, the fulfillment of administrative or ceremonial responsibilities, and the undertaking of agricultural activities, all of which constrain the amount of household labour available for fishing. In the concluding section, I consider the potential role of TURFs in a formal management context. I show that, in the long term, even formally recognized TURFs would not be sufficient in themselves to prevent overfishing. I therefore propose that Lake Titieaca TURFs be incorporated into a broader, decentralized management strategy which would capitalize on their strengths and promote cooperation between members of shore communities, fisheries scientists and administrators. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

Two biomass indicators (direct counts and ATP analysis) and two activity estimators (glucose uptake and dehydrogenase activity) were used to study the bacteria at 1 m water depth in Marlon Lake sediments. Direct count-biomass estimates for bacteria averaged 0.6l gC/m², were high in summer, declined rapidly in fall, then increased during the winter. Microorganisms less than approximately 30 μm diameter had a mean biomass of 1.28 gC/m² as measured by ATP analysis. Seasonal variations in this figure paralleled changes in the algal population, although algal contributions to the microbial biomass were less than 50 per cent. ATP analysis was also used to estimate the biomass of the sediment community, excluding animals greater than approximately 5 mm in length. The mean community biomass was 4.69 gC/m². Comparison of ATP data with enumeration data obtained by others, suggests that ATP is a good biomass indicator, except when cellular ATP levels are changed in reaction to biotic or abiotic environmental factors. It is proposed that, in situations such as intense grazing or rapid Increases or decreases in temperature, ATP measurements reflect not only biomass but also activity. At such times ATP-biomass data may Indicate biomass potential, or the capacity of the population to maintain its biomass under abnormally high rates of loss. Dehydrogenase activity, or respiratory potential, of the sediment bacteria was assayed using trlphenyl tetrazolium chloride. The estimate for annual rate of carbon loss as CO2 from the bacterial population (19.3 g C/m²•year), was almost identical to previously reported data obtained by measuring oxygen consumption in normal and antibiotic-treated sediment cores. Uptake of ¹⁴C-glucose was determined in mixed, diluted sediments. The maximum uptake rate (9.6 g C/m².year), natural uptake rate (5.3 S C/m².year) and the natural turnover time (0.31 h) were similar to previous data for these sediments. This suggests that, at least in terms of function, the bacterial population is quite stable from year to year. Biomass and activity of the Marion Lake sediment bacteria were found to be in phase in late spring through early fall, but activity remained low in winter despite Increases in the microbial biomass, and increased much more rapidly than biomass in early spring. The dynamics of the bacterial population are discussed in terms of these relationships. The size of the algal and bacterial populations and organic matter reservoirs, and the flux rates for carbon between these compartments are summarized. / Science, Faculty of / Zoology, Department of / Graduate

Meiofaunal distribution and abundance were studied in Marion Lake, a small, shallow (8m maximum) oligotrophic lake in southwestern British Columbia. Experimental techniques were used to investigate the influence of food and predation on meiofaunal populations, and to estimate relative carbon -flow to all components (micro-, meio-, and macrofauna) of the zoobenthic community. In two years' sampling of over 50 species of meiofaunal rotifers, nematodes, copepods, cladocerans and halacarine mites, only a few species were abundant. Three depth zones were sampled (1.0, 2.5, 4.5m) and maximum densities occurred at 2.5m. Population densities of all groups were stable over the sampling period, fluctuating less than one order of magnitude annually. In culture studies, representative meiofaunal species had longer generation times and lower reproductive rates than expected. Attempts to use laboratory results to predict field population dynamics were generally unsuccessful, but led to clarification of reproductive parameter estimates. Experiments in the laboratory and in the field suggested that meiofaunal species are not food-limited. Predation on meiofauna is not heavy but might be significant for those species whose reproduction is suppressed by adverse temperatures. Radiotracer experiments indicated that carbon flow to the zoobenthic community from sediment microflora was partitioned approximately 12% to microfauna (ciliates), 12% to meiofauna, and 76% to macrofauna, while the contributions to zoobenthic biomass were 1%, 7% and 92% respectively. In related experiments, a common harpacticoid copepod species had a high assimilation efficiency but rapidly respired and excreted recently ingested carbon. Meiofaunal organisms are apparently not an important food source for higher trophic levels in Marion Lake but may play a significant role in stimulating microfloral production by their grazing activity. / Science, Faculty of / Zoology, Department of / Graduate

Histories o f childhood and youth have generally focused upon social policy toward young people. This dissertation chronicles the actual experiences of youth growing up in and around Williams Lake in the Cariboo-Chilcotin region of British Columbia, a "western" community surrounded by open spaces, ranches, and Aboriginal reservations. Williams Lake underwent economic, demographic, spatial as well as social transformation in the first three decades following the Second World War. Forty-three oral interviews with two sets o f subjects who were adolescents in the study area furnished the bulk of the primary evidence. Most of the first "generation" were bom in the Great Depression and were teens sometime between 1945 and 1955. The second generation are "baby-boomers" bom between 1947 and 1962 who were teens between 1965 and 1975. This joint narrative details select aspects o f their lives at school, at paid and unpaid labour, with friends, and at leisure. It suggests changes and continuities in the experience of local youth between 1945 and 1975. First generation non-Aboriginal subjects grew up with a somewhat coherent peer group albeit with relatively little physical and social contact with Aboriginal youth. Gendered domestic labour around home and property honed work skills and dispositions from an early age. The emergence of local sawmills greatly expanded work options for males but not females. Males also enjoyed comparatively more spatial and temporal freedom throughout their youth. Second generation subjects grew up in a context of greater urbanization and access to mass culture. The merger of regional youth in the high school along with natural population growth, demographic change including the enrollment of first Aboriginal and then Indo-Canadian youth encouraged factions as well as cultural gulfs among youth in the school and community. Their leisure was comparatively less divided, at least on the basis of gender, as many non-Aboriginal parents eased traditional restrictions upon daughters. With notable exceptions this generation contributed less labour to their household and directed part- and full-time earnings into satisfying their own personal interests. The author suggests the pattern of youths' recreational use of hinterlands during the period reflects common practice in many Canadian communities located in similar rural and isolated settings. He illustrates how factors such as family affluence and circumstances, gender, "race" and ethnicity continued to mediate the experience of growing up in this post-war period. He concludes many more local accounts of the experiences of youth are needed before any attempt is made at an inclusive national historical synthesis of growing up in Canada after the Second World War. / Education, Faculty of / Educational Studies (EDST), Department of / Graduate