Stream ecology is dominated by studies that describe the distribution of invertebrate populations and communities. Many of these studies make untested assumptions about the various ecological processes that influence these distributions. The most common assumption, which is often unstated, is that distribution patterns reflect habitat selection by individual animals. However, very few studies have directly tested the relative importance of this process or considered other processes that may also affect the distribution of stream invertebrates. In this thesis I use a correlative survey in combination with manipulative field experiments and behavioural observations to investigate the factors and ecological processes that are associated with the distribution of hydropsychid caddisfly larvae in rocky upland streams in southeastern Australia.

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Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 147-153). Description: xi, 153 leaves : ill. ; 29 cm.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 62-69). Description: viii, 68 leaves : ill. ; 29 cm.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 157-169). Description: 169 leaves : ill. ; 29 cm.

xxii, 242 p. : ill. (some col.) / The arminacean nudibranch Janolus fuscus (family Zephyrinidae) is found in rocky intertidal habitats along the northeast Pacific coast. Adult J. fuscus are conspicuous from April to October but absent in the early winter at two sites, North Cove and Fossil Pt., in the Coos Bay region of Oregon. Over four years of intertidal surveys at these sites, the density of J. fuscus peaked with the abundance of their bryozoan prey, Bugula pacifica and Tricellaria circumternata , in spring and summer, while adult absence in winter was correlated with strong winter storms. To describe the timing of development and determine the life cycle of J. fuscus , embryos and larvae were reared in the laboratory and examined with light, scanning electron, and confocal microscopy. Larvae reared in the lab and juveniles collected from the field were monitored to quantify growth. Janolus fuscus exhibited typical spiral cleavage and hatched as planktotrophic veligers that grew for over a month before they reached competency, settled, and metamorphosed on their prey, B. pacifica . Juvenile growth was rapid, and adults reached maximum sizes of over 50 mm before dying. These demographic and developmental studies suggest that J. fuscus is a subannual species with a life span of approximately five months. Janolus fuscus is often infected with an endoparasitic copepod, Ismaila belciki . In the field, prevalence of I. belciki increased with host density and size. The distribution of I. belciki was weakly aggregated in the host population. The large female parasite was generally found in the anterior portion of the host hemocoel, and one or more dwarf males were typically associated with each female. Infected J. fuscus produced significantly smaller egg masses with fewer larvae than did uninfected individuals. Infection did not influence growth rate but did cause decreased survival in older nudibranchs. To examine the life cycle of I. belciki , naupliar larvae were reared in the lab and incubated with potential hosts. Additionally, copepodid stages were described from dissected J. fuscus collected from the field. Ismaila belciki has a least three planktotrophic naupliar stages and four copepodid stages in its life cycle. / Committee in charge: Barbara Roy, Chairperson; Craig Young, Advisor; Richard Emlet, Member; Sandra Brooke, Member; Frances White, Outside Member

Made available in DSpace on 2016-01-13T13:27:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-27. Added 1 bitstream(s) on 2016-01-13T13:32:33Z : No. of bitstreams: 1 000854796.pdf: 3287498 bytes, checksum: 5389246fc289aed76f7b12139edf692c (MD5) / Estudos para produção de formas jovens de peixes são fundamentais para o desenvolvimento da piscicultura e o manejo das populações naturais. Leporinus agassizii é apreciado nas distintas modalidades de pesca (comercial, artesanal, ornamental e esportiva), além de apresentar características desejáveis para a criação. Objetivou-se descrever o desenvolvimento embrionário e a densidade de estocagem de larvas do aracu-riscado, L. agassizii. Reprodutores foram submetidos a reprodução induzida por hipofisação, com a temperatura da água a 28,6 ± 0,7ºC, no Centro de Capacitação e Produção de Alevinos, pertencente ao Instituto Federal de Educação Ciência e Tecnologia, São Gabriel da Cachoeira, Amazonas, Brasil, no mês de setembro de 2014. Logo após a fertilização, os ovos foram mantidos em incubadoras (60L), com a temperatura média da água de 28,4 ± 0,7 ºC. Coletaram-se amostras de ovos em intervalos de 10 min, durante as primeiras três horas pós-fertilização (PF) e, posteriormente, em intervalos de 30min até a eclosão das larvas, para observação em estereomicroscópio equipado com câmera CMOS digital colorida, 10.0 MP e software para captura e análise de imagens (ISCapture). O efeito da densidade de estocagem de larvas do L. agassizii foi avaliado ao longo do 4º e 14º dias após a eclosão (DAE). Foram utilizadas 3600 larvas no 4º DAE, encontrando-se estas com o saco vitelínico totalmente absorvido, boca aberta e mantidas em jejum. As larvas foram submetidas às densidades de 5 (D5), 15 (D15) e 25 (D25) larvas.L-1, em caixas de polietileno (0,63 x 0,45 x 0,32 m), com 20 L de água. Utilizou-se um delineamento inteiramente casualizado com quatro repetições. As larvas foram alimentadas seis vezes ao dia, sendo cada refeição composta por náuplios de Artemia, na proporção 50 náuplios.larva-1 (4º ao 6º DAE), 100 (7º ao 9º DAE), 200 (10° ao 11º DAE) e 400 (12º ao 13º DAE) e por ração... / Studies for the production of young fish shapes are key to the development of fish farming and the management of natural populations. Leporinus agassizii is appreciated in the different fishing methods (commercial, craft, ornamental and sports), and present desirable features for creation. This study aimed to describe the embryonic and larval stocking density of aracu-riscado, L. agassizii. Players underwent reproduction induced hypophysation, with the water temperature at 28.6±0.7 °C, the Centro de Capacitação e Produção de Alevinos belonging to the Instituto Federal de Educação, Ciência e Tecnologia, São Gabriel da Cachoeira, Amazonas, Brazil, in September 2014. After fertilization, the eggs were kept in incubators (60 Litre), with the average water temperature of 28.4±0.7 °C. Samples were collected 10 min intervals on eggs during the first three hours after fertilization (AF) and thereafter at intervals of 30 minutes until the outbreak of the larvae, for observation in stereo equipped with digital color CMOS camera, 10.0 MP and software to capture and analyze images (ISCapture). The effect of larval stocking density of L. agassizii was assessed over 4th and 14th days after hatching (DAH). 3600 larvae were used in the 4th DAH, meeting these with the yolk sac fully absorbed, mouth open and fasted. The effect of larval stocking density of L. agassizii was assessed over 4th and 14th (DAH). 3600 larvae were used in the 4th DAH, meeting these with the yolk sac fully absorbed, mouth open and fasted. The larvae were subjected to density of 5 (D5), 15 (D15) and 25 (D25) larvas.L-1, in polyethylene boxes (0.63 x 0.45 x 0.32 m) with 20 Litre of water. We used a completely randomized design with four replications. The larvae were fed six times a day, each meal consisting of Artemia in the proportion 50 náuplios.larva-1 (4th to 6th DAH), 100 (7th to 9th DAH), 200 (10th to 11th DAH) and 400 (12th to 13th DAH) and commercial diet ...

Made available in DSpace on 2014-06-11T19:25:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-21Bitstream added on 2014-06-13T18:53:09Z : No. of bitstreams: 1 aguirregil_oj_me_jabo.pdf: 820756 bytes, checksum: 73aa85c9cdc05d6bc69ba37795d60c4b (MD5) / O objetivo do trabalho foi gerar informações sobre alguns parâmetros biológicos de Chrysomya megacephala sob diferentes situações, como tipos de dietas, densidades larvais e quantidades de dietas. Foi adotado um delineamento fatorial de 4x3x3 (4 tipos de dietas, 3 densidades larvais e 3 quantidades de dietas). Estas informações são importantes para o planejamento da produção comercial de larvas, como alternativa na alimentação de peixes, rãs e pássaros. O incremento da porcentagem de farelo de arroz nos tipos de dietas prolongou a duração do período larval, além da diminuição na viabilidade larval e no peso total médio de larvas. No parâmetro densidade larval, a duração do período larval foi relativamente estável, a maior viabilidade larval foi atingida pela densidade de 5 larvas/g de dieta e o maior peso total médio de larvas foi obtido na densidade de 10 larvas/g de dieta. O incremento das quantidades de dietas provoca estabilização da duração do período larval e da viabilidade larval, além da diminuição constante do peso total médio de larvas. Na análise de interação de fatores, os parâmetros biológicos estudados apresentam a mesma tendência encontrada nos tipos de dietas indicando diminuição da duração do período larval e peso total médio de larval com aumento da viabilidade larval conforme incrementam as densidades larvais e quantidades de dietas. No geral, os parâmetros biológicos estudados são afetados pelo incremento da porcentagem de farelo de arroz na dietas mesmo nas diferentes densidades larvais e quantidades de dietas. / The objective was to get information about larval period, larval viability and total weight of larvae rearing on different situations, such as diet, larval densities and quantities of diet. Foi adotado um delineamento fatorial de 4x3x3 (4 tipos de dietas, 3 densidades larvais e 3 quantidades de dietas). It was used a factorial design 4x3x3 (4 diets, 3 larval densities and 3 quantities of diets). These information are important in the planning of larval production, as alternative food of animals, like fish, frogs and birds. The increase of percentage of rice ban increased the duration of larval period, and decreased the larval viability and the average total weight of larvae. In the larval densities, the duration of larval period was stable; the major viability was reached in the larval density of 5 larvae/g of diet and the major average total weight of larvae was in 10 larvae/g of diet. The increase in the quantity of diet, promoted stabilization in the duration of larval period and larval viability, and the constant decrease of the average total weight of larvae. In the analyses of factorial interaction, the biological parameters in study showed the same trend found in the diets suggesting decrease of the duration of larval period and average total weight with increase of larval viability when increase the larval densities and quantities of diets. In general, the biological parameters are affected for the increase in the percentage of rice ban in the diets, even in different larval densities and quantities of diets.

Mangrove habitats are considered as the ideal fish nursery as they are known to increase the growth and survival of juvenile fishes by providing enhanced food availability and protection. However, most studies have focused on tropical mangroves with a few recent warm temperate studies finding conflicting results. Furthermore, the nursery value of South African mangroves to fishes remain understudied in subtropical areas, while warm temperate mangroves are yet to be evaluated. This study aimed to assess whether mangrove presence leads to any advantage to the larvae of an important estuarine resident fish species, Gilchristella aestuaria, by comparing the food patch quality of South African warm temperate mangrove and non-mangrove estuaries. Results indicate that larvae fed primarily on the dominant prey species, Pseudodiaptomus hessei, Paracrtia longipatella, and Acartiella natalensis. However, postflexion larvae consumed more of the larger species, P. hessei, within the two mangrove estuaries (16.09 %V in Nahoon and 13.79 %V in Xhora) than the two nonmangrove estuaries (12.20 %V in Gonubie and 7.05 %V in Qora), despite other prey species occurring at similar densities. Results indicate that mangrove habitats acted as sediment sinks, slightly reducing the turbidity of these estuaries which resulted in postflexion larvae actively selecting larger, more nutritious prey, which in turn, significantly increased their individual instantaneous growth rates (0.11 ± 0.21 Gi) when compared to postflexion larvae in non-mangrove estuaries (0.09 ± 0.12 Gi). This study found that mangrove presence was significantly related to postflexion larval densities when coupled with abiotic (such as temperature and turbidity) and biotic factors (such as predator-prey interactions). Understanding the spatial and temporal dynamics, predator-prey interactions as well as the growth and survival of G. aestuaria is particularly important as they are key zooplanktivores that are prey to other species in estuarine food webs.