Nearshore larval fishes were collected with an oblique trawl tow during day and night from mid-May to August 2010 and 2011 in the Indiana waters of Lake Michigan to determine diel differences in the distribution, depth, and abundance of larval fishes. Alewife, spottail shiner, yellow perch and round goby were the prevailing larval species. Alewives dominated the catch and were in highest abundance near East Chicago. In general, night catch rates were greater when compared to day catch rates, suggesting a diurnal difference in trawl susceptibility. Stratified larval trawling was subsequently conducted during June and July 2011 to detect whether diurnal vertical migration existed, potentially affecting day and night catch rates. Vertical migration was not detected in the stratified larval sampling, eliminating it as a factor in higher nighttime catch rates. Further, the most common fish, alewife, was measured (TL) to determine whether size was a factor in trawl avoidance and to provide information regarding trawl selectivity. Night trawls yielded larger size classes of alewife, potentially explaining higher nighttime catch rates. These data suggests a size bias of our larval trawl exists when comparing day and night samples, as well as the limited efficiency of our trawl to catch larger larval size classes. / Department of Biology

Larvae of Ae. triseriatus mosquitoes were collected from treeholes on the Ball State University campus. These insects were raised to adulthood under laboratory conditions. Newly hatched larvae were raised in deionized water. One hundred twenty-five of instar 1 mosquitoes (group A) were placed into separate baby food jars containing deionized water. These jars were separated into five groups. The pH of the water in each group was adjusted to 3, 4, 5, 6 and 7 with a 70% to 30% sulfuric-nitric acid solution. Subsequent groups consisting of instar 2, 3 and 4 larvae and pupae (groups B, C, D and E respectively) were exposed to the same experimental treatment as that of group A. The effects of each of these pH levels on mortality and development was observed until the insects reached maturity or died.Larvae in water of pH 3 experienced a higher percentage of mortality than mosquitoes exposed to less acidic solutions. A decrease in mortality with age was observed. Mortality of insects in group A was greater than that of any other group. Mosquitoes in group D experienced the lowest mortality.Variations of developmental time for mosquitoes in pH 3 were probably due to high mortality. Developmental time was similar for all groups. Slight variations between these groups may have been due to natural fluctuations in development. The total average developmental time for Ae. triseriatus mosquitoes of this study was 11.12 days.

This thesis has examined the influence of the environment on aspects of the acute stress response in juvenile and pro-larval Acipenser fulvescens.The acute stress response was examined in grouped and isolated juveniles. Catecholamines significantly increased in both treatments one minute post-stress and plasma glucose was significantly higher in isolated as compared to grouped fish one minute post-stress. In the second series of experiments fertilized eggs of A. fulvescens were raised at 9, 12 & 15°C. Chromaffin-like cells were studied using light and electron microscopy techniques. Development of renal tissue was also examined in these treatment groups. Two populations of chromaffin-like cells were identified, one in close association with the proximal tubule of the kidney, and the other in close association with the neural tube. Results suggest this latter population were immature pheochromoblast like-cells. Development of renal tissue followed a predictable pattern that was most rapid in the 15°C treatment.

No description available.

In this study, predation efficiency of three guppy ( Poecilia reticulata) size classes was evaluated at various vegetation densities in a series of circular aquaria containing plastic plants closely resembling Ceratophyllum demersum. The effect of vegetation density was most apparent among large fish where predation efficiency greatly diminished from 12.35 mosquito larvae (Aedes aegypti) to 4.68 as vegetation densities rose from 3 to 19 plants/700 cm2. Over that same range of increasing vegetation densities, predation among small fish remained unchanged, whereas among fish of intermediate size predation declined significantly but less precipitously than for large individuals. When presented with a choice between second and fourth mosquito larvae, small fish preferred to prey on second instars, whereas large fish preferred fourth instar larvae. Fish of intermediate size did not show a statistically significant preference. The functional response of fish to increasing prey densities, as measured over a 12-h period, was of Type III.

The effects of food availability and selective control of late instar larvae of Aedes aegypti on preimago population structure, mortality, adult abundance, sex ratios, and size of females were examined. Food availability i an important factor in determining preimago population structure and mortality. At optimal food availability more adults emerged, females were larger and in higher proportions than at suboptimal food availability. The effects of selective control on preimago population structure and post treatment larval mortality differed with food availability. At suboptimal food availability the type of control applied had a significant effect. Simulated pathogen-induced mortality resulted in a shift of the population to late instars and temporarily reduced density dependent mortality. The findings suggest that although both pathogens and predators reduce intraspecific competition by directly killing competitors, pathogens also provide an influx of food. Compensatory mortality may result from a reduction of intraspecific competition caused by biocontrol agents.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1991. / Includes bibliographical references (leaves 125-138) / Microfiche. / xv, 138 leaves, bound ill. 29 cm

Nine series of vertically-stratified zooplankton tows were made with a closing net at a single station in southern Kaneohe Bay, Oahu, Hawaii, between 31 August 1973 and 11 April 1974. Sampling periods occupied from 12 to 26 hours, with tows usually taken at about 3 m intervals between the surface and a maximum depth of 10 m. A total of 21,254 fish larvae of 49 kinds was collected. Six species were abundant: Foa brachygrammus, Omobranchus elongatus, Callionymus decoratus, Caranx mate, Stolephorus purpureus, and Abudefduf abdominalis. Blennius sp. and Gnathanodon speciosus were commonly taken in small numbers. These common larvae displayed five "distribution patterns: 1. F. brachygrammus and the smallest S. purpureus were most abundant near the surface at night and at depths below 4 m during the day; 2. C. mate and G. speciosus were dispersed throughout the water column at night and usually most abundant between 5 m and 6 m depth during the day; 3. Blennius sp., o. elongatus, and A. abdominalis were dispersed throughout the water column at night and concentrated near the surface during the day; 4. the larger ~. purpureus maintained a level of maximum abundance below 6 m day and night; 5. C. decoratus was taken at all depths at all times. Patterns 1, 2, and 3 are shown to be light-related. Pattern 4 is shown to be partially attributable to avoidance of the towed net by S. purpureus larvae larger than about 6mm, and a feeding-related migration is proposed to account for pattern 5. The observed patterns are analogous to those shown for fish larvae in the open ocean on scales of from 50 m to 200 m. It is proposed that Kaneohe Bay represents a vertically compressed ocean with respect to the vertical distribution of fish larvae. / Typescript. Bibliography: leaves 130-134.

New Zealand�s fourteen deep-water fiords have complex physical and hydrographic features as well as strong environmental gradients, all of which may influence the population structure of organisms that inhabit the fiords. I examined the population structure of the brachiopod Terebratella sanguinea over ecological and evolutionary time scales in relation to physical and hydrographic features of the fiords. To further explore the role of larval dispersal in this system, comparisons between population genetic structure of T. sanguinea and a brachiopod with a contrasting larval dispersal strategy (Liothyrella neozelanica) were made. Aspects of the life history of the articulate brachiopod Terebratella sanguinea were measured. I measured density and size throughout Doubtful Sound and growth at outer (5 km from outer coast) and inner fiord sites (13.5 km from outer coast). Additionally, reproductive periodicity was measured at a single site within Doubtful Sound. Terebratella sanguinea occurred at significantly lower densities and was significantly smaller at the outer fiord site (p < 0.05), however growth rates between an inner and outer fiord site did not differ significantly. Terebratella sanguinea was found to have separate sexes and synchronous maturation of oocytes with spawning occurring in the austral winter. These results indicated that, on an ecological time scale, the environmental gradient of the fiords influences aspects of T. sanguinea population structure. In order to determine the influence of the fiord environment on genetic population structure, patterns among T. sanguinea from across Fiordland were assessed using two genetic markers, and these data were compared to hydrodynamic variables. Ten sites (322 individuals) were included in a preliminary allozyme analysis, and 20 sites (358 individuals) were used for the amplified fragment length polymorphism (AFLP) analysis. Patchy genetic differentiation was revealed with both markers, and a break between Long Sound and the other Fiordland sites was detected with AFLP markers. My results suggest hydrodynamic features of this region may isolate organisms that can disperse only during a planktonic larval phase, however this isolation is visible in genetic patterns only at the most extreme values of the hydrodynamic variables. To better understand how the fiord environment influences population structure of organisms that disperse via planktonic larvae, I compared population genetic structure of two sympatric brachiopod species that differ in planktonic larval duration. Genetic analysis using the AFLP technique revealed population structuring corresponding to the contrasting modes of larval dispersal. AMOVA analysis indicated Liothyrella neozelanica, a brachiopod that broods its larvae, had more limited exchange among sites within a fiord than did T. sanguinea, a brachiopod that does not brood its larvae. In general, the fiord hydrographic conditions may be creating opportunities for local genetic differentiation (for example Long Sound) in organisms capable of longer distance dispersal, but organisms with lower potential for dispersal are more strongly influenced by ontogeny than by hydrography. Understanding the population structure of some of the marine fauna of Fiordland is an important cornerstone for the developing management plan for the area. Conservation of the underwater resources of this World Heritage Area can be successful if the structure of the system and the mechanisms driving this structure are taken into account.

Abstract Experiments in this thesis were conducted to investigate the possibility of bestowing lambs with increased resistance to gastrointestinal parasites through maternal protein and copper supplementation. Reproductive outcomes such as birth weight, haematological parameters and faecal egg counts were used as indices of possible foetal programming. This thesis involved 5 experiments. The first three experiments were done using rats as a preliminary study animal on account of their short generational intervals and high fecundity. The final two experiments involved Merino sheep. The first experiment in Chapter 4 investigated the most optimum larval dose to use in order to elicit a measurable immune response. Weaned offspring were infected with a rat nematode, Nippostrongylus brasiliensis and their response measured by faecal egg counts, parasite recovery from intestines at sacrifice, spleen weights and leucocyte numbers, especially manifested as eosinophilia. There was no significant difference in parasite rejection for rats infected with 1000 larvae/rat. When rats were infected with variable larval doses to determine the optimum dose rate, eosinophilia and spleen weight were significantly increased as dose rate increased from 500 L3 to 2,000 larvae. Based on these results, it was decided to use 1,000 larvae for each rat in Chapter 6. The experiment in Chapter 5 involved feeding diets with 5 graded concentrations of copper (Cu) ranging from deficient (1 ppm diet) to high (16 ppm diet). Rats were fed for 4 weeks before mating after which half of them were sacrificed to determine liver Cu concentrations and haematological parameters. The rest were mated and maintained on their respective Cu diets into the second trimester of pregnancy. Pregnant females were sacrificed on approximately gestational Day 10 to recover foetuses and determine the incidence of foetal defects, foetal Cu status as well as maternal liver copper status. It was determined that most morphological defects occurred for the 1 ppm foetuses and both 2 ppm and 4 ppm had similar incidences of brain enlargements. The 16 ppm copper diet was excessive evidenced by reduced liver iron status and erythrocyte counts to similar levels as for 2 ppm rats although it had no adverse effect on foetal development. Significant differences were found for liver Cu status, erythrocyte counts and spleen weights due to the copper diets. A deficient copper diet containing 1 ppm Cu (LC) and an adequate diet containing 8 ppm Cu (SC) were used for the last rat experiment in Chapter 6 which was funded by the Science and Innovation Award. The LC diets were fed for 4 weeks prior to mating. Rats were then fed LC throughout pregnancy, for the 1st trimester only or for the 1st and 2nd trimesters. Other pregnant females were fed the SC diet throughout pregnancy. Offspring were challenged with 1000 L3 N. brasiliensis and their immune responses measured. Copper deficiency at variable stages of prenatal development caused significant postnatal mortalities but had no effect on response to parasite resistance. However, significant parasite and sex effects were found for parameters such as spleen weight, eosinophilia and weight loss during infection. The foetal brain enlargement caused by the deficient 1 ppm Cu diet was determined to be reversible in vivo upon exposure to a normal 8 ppm Cu diet during gestation. Chapter 7 involved Merino ewes which were fed either a high protein diet (21%) or adequate protein diet (12%) during the first 2 trimesters of pregnancy. Production parameters measured included pregnancy weight gain, fleece yield, protein content in milk as well as birth weight of lambs but none were significantly different. After weaning, the lambs were experimentally infected with 10,000 Haemonchus contortus larvae. Barber’s pole worm is responsible for millions of dollars in production losses in the sheep industry. Responses measured were eosinophilia, faecal egg count, anaemia (PCV) and weight gain/loss during the infection period. No significant differences were found for any parameter tested except for a parasite effect on erythrocyte numbers and PCV. In Chapter 8 Merino ewes were used which were mildly Cu deficient due to grazing on pasture that was copper deficient. Control ewes were supplemented with copper oxide wire particles at mating and mid-pregnancy. The rest of the experiment was the same as for Chapter 7 in terms of Barber’s pole worm larval dose. There were no significant differences in birth weight, weaning weight or ewe fleece weights due to copper status. There were no differences in parasite resistance in the lambs due to maternal Cu status measured by live weights, eosinophil concentrations or faecal egg counts. In conclusion, foetal programming by maternal nutritional supplements for postnatal parasite resistance appears to be impossible. It may be that if a different organ was targeted, such as the spleen, the results would have been different. The thymus appears to be non-programmable during foetal development in rats and sheep. However, it was a worthwhile attempt at conferring resistance to parasites in lambs due to the urgency in combating the global problem of parasite resistance to anthelmintics and the resultant large economic losses that are experienced by the global sheep industry.