Thesis (M.A.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

ix, 55 p. : ill., maps. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Aggressive behaviors in many animals increase juvenile survival and reproductive success. I explored the role of aggressive behavior in maternal care and male-male competition in caprellid amphipods. Attacks of females in three reproductive states toward male and female conspecific and congeneric caprellids were quantified. Parental females showed greatest aggression toward males of both species, suggesting these caprellids may pose threats to juveniles. Paired males were exposed to females in three reproductive states and other males and fought most often in the presence of nonbrooding females. This finding suggests that males recognize and fight over receptive females. Males fight with the second gnathopods and "poison tooth," which may cause fatalities in conflicts. Mortality rates of males with and without (removed) poison teeth were not significantly different, but the highest observed mortality rate was no-tooth caprellids when paired with toothed males, suggesting presence of the teeth may impact the outcome of male-male conflicts.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 94-98). Description: vii, 98 leaves : ill. ; 29 cm.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 283-301). Description: xxx, 301 leaves : ill. ; 29 cm.

This thesis utilises a range of methodologies to investigate the historical shoreline change and beach morphodynamics at Rapahoe Bay, West Coast, New Zealand. Rapahoe Bay is a small embayment located 15 km north of Greymouth, and contains a complex and dynamic environment under a dominant swell condition. The objectives of this thesis include the investigation the coastline history through aerial photographs and relevant literature, identify and quantify historical shoreline change and the processes that have induced change, examine the short term and seasonal changes in beach profile, identify and quantify wave and transport process and to test the applicability of the zeta shoreline curve on a composite beach. This combined approach investigates the dynamics and process drivers involved in coastline change. This thesis contributes to the research gap of understanding morphodynamic behaviour and controls of composite beach under a dominant swell. Composite beaches types are a variation from mixed sand and gravel beaches with distinct morphological differences. This thesis provides an insight in to the morphodynamic behaviour of composite beaches. The study area contains a small village based by the shoreline and the potential coastal hazard that threatens people, property and infrastructure. Therefore the results from this thesis have an important management implication towards mitigating coastal hazards. The historical coastline change was induced through a combination of wave processes and transport, composite beach morphodynamic behaviour, anthropogenic influence and planform shape. Results show that human infrastructure restricted the retreat of a small hapua landward of the gravel barrier. A combination of change in sediment supply, consistent sediment transport and a high wave energy environment resulted in rapid landward retreat through gravel rollover and coastal erosion. The gravel barrier morphodynamics include increase in crest elevation, steeper shore gradients as a response to high swells resulting in erosion or rollover. The wave environment includes a sediment transport hinge point due to a dominant wave refraction and changes in the shoreline orientation, which further induces coastal erosion. The valid applicability of the zeta planform shape concludes that the shoreline may further iii retreat due to geological controls, potential sediment transport and the transgressive nature of the composite beaches. The combination of methods and results provide both quantified historical change and also potential future scenarios of coastline reshaping. These methods and results are applicable not only to Rapahoe but along other West Coast composite beaches, and the validity of the combination of methods provides a greater understanding of the behaviour of morphodynamic composite beaches and provides quantified results of historical shoreline change and sediment transport at the field site.

The life cycle of Callianassa californiensis Dana, 1854, was studied in the tidal estuary, Yaquina Bay, Oregon. At this latitude it is largely restricted to intertidal sandy mudflats under predominately marine influence. Salinity and temperature appear to determine its distribution to a greater extent than does sediment type. Vertical movement within the sediment is related to the tides on a day to day basis and to temperature on a seasonal basis. Large-scale breeding generally begins in the spring, and ovigerous females may be plentiful in the cooler layers of mud until August. It is not clear what triggers larval release, but temperature and tidal conditions seem to be important. All five zoeal stages are found in the plankton from the mouth of the bay to three miles offshore during late spring and summer. Nearshore waters appear to act as a larval reservoir along this part of the coast, and successful larval settlement may depend upon high-tide transport into a bay. / Graduation date: 1972

During the six-month period of July through December, 1966, a study of animals inhabiting laminarian holdfasts in Yaquina Bay, Oregon, was carried out to determine what animals live in this habitat and to gain some idea of the factors which influence their presence and distribution. This study deals with yet another facet of the ecology of this Oregon estuary, which has been the object of intensive biological, geological, and hydrographic studies for the past several years. Fifty samples were collected and analyzed and found to contain a total of 6,687 individuals representing 99 taxa. Identification was carried to species as far as possible although several individuals were juvenile or incomplete and so could be determined only to higher taxonomic levels. Some species showed limited distributions, but most species were widespread spatially and seasonally. The species composition of the samples at a given location was quite constant throughout the period of sampling, but at each time of sampling it varied markedly among different locations in the bay. Since the animals found in holdfasts also occurred in other situations offering shelter and evidently readily moved from one holdfast to another, it was impossible to define any unique holdfast community. When the animals taken were lumped by group, the most numerous were polychaetes, which comprised twenty-eight percent of all of the individuals. Other groups present in relatively large numbers were pelecypods, nematodes, cirripedes, and gastropods. There have been no other studies of holdfasts-inhabiting animals in estuaries reported from the Pacific coast, so the results found were difficult to compare with other findings. Other surveys have been made on this coast which dealt with animals living in holdfasts in oceanic situations, and the results of the present study were somewhat comparable to them. / Graduation date: 1967

The Hemigrapsus oregonensis population at Coquille Point in the Yaquina Bay Estuary on the Central Oregon Coast was studied from April, 1972 through May, 1973. The population was found to be vertically stratified from the 1 ft level to the 5 ft level. Population densities were found to be most dense in the upper regions. Greatest population density (about 20 crab/m²) was found to be in the 3-4 ft interval above MLLW (0.0 ft level). The population sex ratio was biased in favor of the females (53.3%) and did not vary appreciably during the year. The reproductive season, as determined by the percentage of berried females, was from February through May with a peak (32.8%) during March. Brooding females were found every month during the study, indicating a continuous, low level egg production throughout the year. A model for estimating potential egg production is given. The minimum carapace width of brooding females was found to be 0.86 cm. Biomass values were determined from carapace width measurements. A conversion equation is given. Biomass values generally increased as tidal height increased. The average biomass value for the area was 8.47 g/m². The average dry weight per crab decreased as tidal height increased, The average dry weight per crab at each tidal height (about 0.5 g) did not significantly increase during the study, suggesting a stable population. The average monthly production showed an over-all negative rate of -1.23 g/m² per month. No significant differences were found between tidal heights. The net production rate at each tidal height could not be shown to be different from a zero net production rate, again suggesting a stable population. Monthly distributional patterns indicated an high degree of population mobility. Crabs tested for locomotory activity patterns in the laboratory showed rhythms influenced by both the light regime and the tidal regime. Weak endogenous displays were found for a light component with increased activity during dark periods. Greatest activity generally occurred during dark-high tide periods. It is suggested that the locomotory activity patterns of H. oregonensis are influenced by both a tidal cycle and a light cycle. Under constant experimental conditions, the endogenous rhythmicity decayed within 3-9 tidal cycles and resulted in more or less continuous random movements. Only about 50% of the tested crabs, however, displayed an endogenous locomotory rhythm. / Graduation date: 1974

In the upper estuary of Yaquina Bay, Oregon, there is an annual population explosion of Acartia tonsa, (Dana) a calanoid copepod, during the months of July, August and September, followed by a rapid decline to virtual extinction in November. The restricted estuarine distribution affords an excellent opportunity to study the factors governing the population dynamics of A. tonsa without the disadvantage of potential mixing with other populations on different schedules of development. Field densities of A. tonsa during the 1972 summer were determined by twice weekly sampling with Clarke-Bumpus plankton samplers. In addition, explanation of the production of A. tonsa in the field was attempted by measuring the rates of egg production and development in the laboratory under temperature (21°C) and salinity (25‰) conditions comparable to those in the upper estuary. Daily egg production was found to be 30.5 eggs*day⁻¹*female⁻¹. The median rate of development from egg to adult required 11.5-11.6 days at 21°C in conditions of either laboratory cultured or wild food organisms. Mortality rates were substantial during the experiments as only 20-30% of the original populations survived to adulthood. The cause of mortality is not known but may relate to the molting process. In the field, six successive generations of A. tonsa were observed during the population explosion. The mean generation time ranged from 16 days in August to 19 days in October. A maximum density of 16,800 adults*m⁻³ in late August was followed by a crash to 2,100 adults*m⁻³ 10 days later. Predation and over exploitation of food resources are two possible causes of the crash. However temperature appears to be the major factor for the subsequent decline and disappearance of A. tonsa in the fall. This thesis presents the first results of ongoing research into the population dynamics of A. tonsa. / Graduation date: 1974

Large-volume (20-liter) bioassays were carried out in order to assess the effects of major nutrients and micro-nutrients on natural phytoplankton populations in water collected from a site close to the mouth of Yaquina Bay, Oregon. Seven long-term experiments were conducted during the years 1975-1976. A stripping technique employing activated carbon was used to reduce the trace metal and dissolved organic load of a portion of the water. Various combinations of major nutrients (nitrate, phosphate, and silicate) and micro-nutrients (trace metals and vitamins) were added to both the carbon-stripped and the non-carbon-stripped water in order to assess the effects of various nutrient substances on the growth rate, biomass yield, and species composition of the phytoplankton populations which developed from small natural inocula. The major nutrients and the micro-nutrients appear to have fundamentally different effects on the species composition and population growth characteristics of the phytoplankton. The micro-nutrients had marked systematic effects on the species composition of the phytoplankton populations which developed in the experimental vessels, while the major nutrients had minimal effects on species composition. The micro-nutrients appeared essential for the achievement of maximal population growth rates and minimal lags, while the major nutrients had no effect on growth rates or lags. Both the major nutrients and micro-nutrients had significant effects on the final biomass yields. There were seasonal variations in the control of final biomass yields by major nutrients and micro-nutrients. / Graduation date: 1977