Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--The University of North Carolina at Greensboro, 2010. / Directed by Anne Hershey; submitted to the Dept. of Biology. Title from PDF t.p. (viewed Jul. 9, 2010). Includes bibliographical references (p. 29-34).

Thesis (M.S.)--Montana State University--Bozeman, 2006. / Typescript. Chairperson, Graduate Committee: Thomas E. McMahon. Includes bibliographical references (leaves 127-139).

Thesis (M.S.) in Earth Sciences--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 106-111).

Universiẗat, Diss., 2002--Kiel.

Techn. University, Diss., 2004--Berlin.

Thesis (Ph. D.)--Oregon Graduate Center, 1984.

The Gander Lake Subzone of northeast Newfoundland preserves a complex tectonothermal evolution resulting from continental collision of Gondwana and Laurentia following closure of the Iapetus ocean. Field, petrographic, geothermobarometric studies and isotopic age data define five northeastsouthwest trending domains, each with a characteristic P-T-t-d evolutionary path, which reveal elements of the overall tectonothermal evolution in this sector of the Appalachians. Domain I preserves deformed low grade metasediments and east vergent flat-lying 02 folds formed at c. 470 Ma. Domain 2 preserves focusing of later progressive deformation (D3wEST) into a steep, predominantly sinistral high strain zone characterised by andalusite ~ kyanite ~ sillimanite indicative of a clockwise metamorphic path (peak conditions c. 650°C, 5.5 kbar). In domain 3, deformed metasediments (D2-D3EAsT) display an eastward increase in structural complexity and metamorphic grade to a peak of c. 600°C. Domain 4 displays progressive amphibolite facies deformation (D3EAsT) characterised by prograde andalusite ~ sillimanite-bearing (c. 425 Ma) migmatites with peak conditions of c. 700°C, 4.5 kbar. Retrograde 04 deformation and metamorphism is concentrated in steep narrow high strain zones. S4WES~amphibolite to greenschist facies shear fabrics (predominantly dextral) overprint prograde fabrics (S3WEST)within domain 2 and are cross-cut by the c. 427 Ma Middle Brook Granite, Locally in domains 3 and 4 prograde (D3EAsT) fabrics are overprinted by amphibolite to upper greenschist facies S4EAST fabrics which also form the dominant fabric in c. 417 Ma syntectonic granites. D5-06 retrogressive deformation is pervasive in a c. 2 km wide mylonitic zone adjacent to the Dover Fault. D5 dextral greenschist-facies ductile structures are cut by the c. 385 Ma Newport Granite which in tum is cut by 06 sub-greenschist facies brittle dextral faults. In combination, the domains preserve A) low grade deformation (Ordovician?) associated with easterly thrusting of the Dunnage Zone over the Gander Zone, B) Silurian rIletamorphism and deformation progressively partitioned into high strain zones and, C) Devonian retrograde ductile-brittle shearing and brittle faulting local to the Dover Fault. The spatial and temporal coincidence of transpressive deformation, moderate to high grade metamorphism and voluminous granite magmatism in the east portion of the Gander Zone is taken to relate to sinistrally oblique collision between two major crustal blocks during the Silurian. Devonian reactivation juxtaposed part of the high grade Gander Zone against the low grade Avalon block across the brittle-ductile Dover Fault.

Diplotaxodon limnothrissa Turner (1995) is a widely distributed species occurring throughout Lake Malawi, extending from the surface to a depth of at least 220m. It is probably the most abundant cichlid in the lake with biomass estimates of around 87 000 tonnes in the pelagic zone alone. The species is exploited commercially in the southern part of the lake but since its inception the fishery has never been assessed. As such this study investigates some aspects of age and growth of the species besides applying a yield-per-recruit analysis to assess the status of the fishery. Analysis of sectioned sagittal otoliths revealed that D. limnothrissa is fast growing and relatively long-lived species, attaining ages in excess of 10 years. Growth in length was rapid in immature fish, with fish attaining almost half of their maximum size within their first year. Le ngth-at-age was described by the von Bertalanffy growth model with combined-sex growth described as Lt = 211.21(1-exp(- 0.24(t+1.36))) mm TL. Total, natural and fishing mortalities were estimated at 0.76 yr⁻¹, 0.31 yr⁻¹ and 0.45 yr⁻¹ respectively. Per-recruit analysis indicated that the D. limnothrissa stock in the southeast arm of the lake is fully exploited as indicated by the current spawner biomass-per-recruit ratios of 31-55% (SB/R)F=0. Modelling indicated that the current age-at-capture (2.67 years) is lower than the age at which yield is optimised (> 5 years) based on the F₀·₁ harvesting strategy. It is, therefore, recommended that the age-at-capture should be increased from 2.67 to 5 years to optimise yield.

Fisheries in African reservoirs are typically multi -species and in most cases the fish resource is harvested with a number of gears. These characteristics complicate their management and the development of management procedures. Typically, long time series of data on catch and effort and length- or age-based catch are not available for these fisheries. This precludes the use of data intensive methods such as multi-species virtual population analysis. The principal aim of this thesis was to develop a management procedure for African reservoir fisheries that takes into account the pertinent biological characteristics of the target species and accounts for the multi-species and multi-gear irIteractions in such fisheries. An opportunity availed itself to undertake this work on Lake ChicaIllba (19°08'S 33°08'E) a man-made hydroelectric dam in subtropical Mozambique (Manica province). The specific objectives of this study were: to obtain locality specific biological parameters for the target species in Lake ChicaIllba; to assess gear utilisation trends in the fishery through the determination of gear-selectivity, catch rate and effort for each of the principal gears used in the fishery; to assess the fishery using traditional per-recruit models and to test existing and new per-recruit models that account for the multi-species and multi-gear nature of the fishery and to determine the adequacy of each of these approaches in the determination of suitable target reference point (TRP) exploitation rates. The three principal specIes in Lake Chicamba are the introduced largemouth bass, Micropterus salmoides, and two cichlids the Mozambique tilapia, Oreochromis mossambicus and the redbreast tilapia, Tilapia rendalli. Sectioned otoliths were used for age and growth determination. Marginal zone analysis showed that annulus formation in all three species occurred during winter. The maximum-recorded age was 5 years for M. salmoides, 16 years for T. rendalli and 10 years for O. mossambicus. Growth of the three species was best described by the 3 parameter von Bertalanffy growth model as ℓa = 465.51 (1 - e⁻ₑ·ₑ⁷⁵⁽a⁺⁰·⁰⁰⁹⁾ mm FL for M salmoides; ℓa = 238.74 (1 - e⁻⁰⁶³⁶⁽a⁺⁰·⁹⁰⁵⁾) mm TL for T. rendalli; and ℓa = 266.06 (1 - e⁻⁰⁷⁹⁰⁴⁽a⁺⁰·²⁶⁹⁾) mm TL for 0. mossambicus. Female T. rendalli attained 50%-maturity at 2.89 years, while O. mossambicus matured at 2.83 years and M. salmoides at 0.9 years. Both cichlid species spawned throughout summer while M. salmoides had a very short spawning season from August to September. The total annual mortality rate (Z) for M. salmoides in Lake Chicamba was 1.27 yr⁻¹, the mean empirical estimate of natural mortality (M) was 0.73 yr⁻¹, and fishing mortality (F) was calculated at 0.54 yr⁻¹. For T. rendalli Z = 0.31 yr⁻¹, M = 0.20 yr⁻¹, F = 0.11 yr⁻¹ and for 0. mossambicus Z= 0.62 yr⁻¹, M= 0.38 yr⁻¹, F= 0.24 yr⁻¹. The three species exhibited reproductive traits, which implied a high reliance of recruitment on spawner stock (nest guarding in T. rendalli and M. salmoides and mouthbrooding in O. mossambicus). For this reason it was decided that the cichlid fisheries should be managed using TRPs which maintained the spawner biomass-per-recruit at 50% (FSB50) of pristine levels. However, based on good evidence it was hypothesised that the high rate of fishing mortality helped to maintain the fast growth rate of M. salmoides. It was, therefore, decided to manage this species at a TRP of F SB40. The three most important fishing sectors were the gill-net, seine-net and hook-and-line fisheries. The total catch for 1996 was 223 t. The gill nets selected all three species at a size/age approximating 50%-maturity while the seine-net and hook-and-line fisheries selected mainly juvenile fishes. There was strong evidence to suggest that seine net fishing also disrupted spawning. It was shown that the 'traditional' single-species per-recruit models were unsuitable to assess multi-species and multi-gear reservoir fisheries. Since existing multi-species/multifishery yield-per-recruit models were not capable of defining FsB(x) TRPs, a new multispecies/ multi-fishery spawner-biomass-per-recruit approach was developed. This approach allowed for the simulation of the response of spawner biomass-per-recruit to changes in effort in the three fishery sectors, simultaneously. The models showed that the spawner biomass-per-recruit, at current effort levels, was higher than the suggested TRP for the three species. However, it was shown that an increase of 10% in current total effort would reduce spawner biomass-per-recruit to below the recommended TRP levels. With the closure of the seine-net fishery, gill-net effort could be increased to 338 fishers (340 for management purposes) and effort in the hook-and-line fishery could be increased by 30% before the TRP was reached. To maintain the fish stocks above TRP levels, effort control was considered to be the most effective management method. The main recommendations for Lake Chicamba were to close the seine-net fishery, to limit the gill-net fishery to 340 fishers (using 137-m long x 3-m deep gill nets) and to maintain the open access nature of the hook-and-line fishery. The multi-species/multi-fishery per-recruit approach allows for the meaningful simulation of various scenarios and provides relatively robust management options. In the absence of long time series of effort and age- or length-based catch data, this approach was considered as the most suitable assessment method for multi-species/multi-gear African reservoir fisheries.