Bibliography: leaves 121-151. Examines seasonal variation in population numbers of Diamondback moths, and estimates mortality, due to parasitoids, of larvae at different stages of development.

from the summer dry season to the winter wet season. Such movement that connects summer and winter habitats may be particularly important for coho salmon, O. kisutch, because availability of overwintering habitat can limit freshwater survival for this species. Here, I describe basin-scale variability in the spatial pattern of fall movement for juvenile coho salmon between mainstem and tributary streams during the fall of 2002, 2003, 2004, and 2005. Juvenile coho salmon were tagged with a passive integrated transponder (PIT) and could be detected at five stationary detection sites, two located in perennial tributaries, two in intermittent tributaries, and one in the upper mainstem of the West Fork Smith River, Oregon. For each detection site, I compare the likelihood of detection during the fall by juvenile coho salmon from tagging locations over a multi-kilometer range of distances in each direction away from the tributary confluence. I developed logistic regression models with data from each detection site to estimate: 1) the relative likelihood of immigration into a tributary as compared to emigration out of the tributary, and 2) the relative likelihood of immigration into a tributary from the mainstem downstream of the tributary confluence as compared to immigration from the mainstem upstream of the confluence. For each pair of directions at each detection site, I also compare the change in the likelihood of detection with increasing distance for each direction. Overall, at the two upper-river detection sites, juvenile coho salmon were more likely to emigrate than to immigrate. At the remaining detection sites, juvenile coho salmon were no more likely to emigrate than immigrate. Of these detection sites, fish that immigrated into the mid-river perennial stream were more likely to come from the mainstem downstream of the confluence, whereas fish that immigrated into the two lower-river intermittent tributaries were more likely to come from the mainstem upstream of the confluence. Fall movement of juvenile coho salmon between tributary and mainstem habitat can occur over relatively long distances. This case study demonstrates variation among tributaries in the overall likelihood of emigration and immigration and in the source of immigrants from the mainstem, which may be related to spatial context that combines the physical characteristics and network position of tributary streams. The demonstrated variation in fall movement that connects summer and winter habitat within a stream network is a first step in exploring how complexity in movement interacts with the spatial arrangement and quality of seasonal habitats. More research on the causes of variation in the expression of fall movement will improve our understanding of how the spatial arrangement of habitat within a stream network influences the survival of juvenile coho salmon over the whole freshwater life cycle. / Graduation date: 2013

Seasonal movements of anadromous brook trout (Salvelinus fontinalis) were studied in riviere au Saumon, James Bay, during 1986 to 1988. A comparison of the biology and energetic parameters between sea run and freshwater brook trout was made in the same system. Anadromous brook trout started their downstream movements in May and displacements peaked in June, but some also occurred in fall. Downstream movements were correlated with spring and fall freshets. Important interannual variation was observed in the movement pattern. Seaward movements of anadromous trout were limited to the brackish waters, as fish congregated at the river mouth. I suggest that movements into brackish waters are passive. Upstream movements began in late July and continued until freezing (November), with the intensity of movement varying annually according to climatic conditions. / Comparison between anadromous and freshwater trout showed very little difference in mean length at age, age at maturity, egg size and fecundity between the two groups. However, examination of energetic parameters indicated that sea run brook trout had a greater increase in condition factor during the summer than the freshwater residents. This raise in condition factor is accompanied by a decrease in water content and a lower water content in the eggs of anadromous fish. These results indicate that benefits associated with anadromous migrations in brook trout reside in the seasonal pattern of energy storage, which is important for the recovery from energy expenditure associated with spawning and overwintering.

Graduation date: 1999

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate some aspects of the biology of the anomuran crab Aegla sp. n.., for example: the size of onset of sexual maturity, the median size between males and females, the sexual proportion (monthly and in size classes), the reproductive period (based on ovigerous females frequency), recruitment, spatial and seasonal distribution and growth in natural environment. This crustacean is a new species which is in process of description. The study was realized in Passo Taquara brook, situated in São Pedro do Sul municipality, in central region of Rio Grande do Sul State. Samplings were monthly realized, from May/2005 to April/2006 in three sections of the stream. Traps containing bovine liver as lure and dip nets were used to collect the animals. Eight traps were placed in each section, with a distance of 10 meters between them. In each section a sampling effort of 20 minutes was realized.. All the captured specimens were sexed by inspection of the presence of pleopods in females and and/or position of the sexual gonopores (coxae of the third pereopods in females and coxae of the fifth pereopods in males). Specimens with less than 3 mm of cephalothoracic length were considered unsexed juveniles due to the impossibility of visualizing pleopods and genital pores. The following corporeal dimensions were measured using a digital caliper with 0.01 mm of precision: cephalothoracic length (CL), cephalothoracic width (CW), width of the second abdominal somite (AW), length of the right chela (RC), length of the left chela (LC) and height of the larger chela (HC). After the data register, crabs were returned to the stream, to the same places where they were collected. A total of 916 specimens was sampled, 17 unsexed juveniles, 601 males (166 juveniles and 435 adults) and 298 females (101 juveniles, 182 adults and 25 ovigerous). The size at the onset of sexual maturity was esteemed, using Mature I and II software, in 13.60 and 10.84 mm of cephalothoracic length for males and females, respectively. Males presented sizes significantly larger than females. The distribution in size classes showed was bimodal for both sexes indicating more than one age-group in the population. The sexual proportion was in agreement with the expected value (1:1) when analyzing the specimens sampled with nets, but differed when analyzing the total data. Ovigerous females were sampled in all stations of the year, but they were more frequent in winter. Juveniles were also sampled in all stations of the years, but more frequently in winter and spring. The water temperature registered in Passo Taquara brook was similar among sections (p>0.05), but it was statistically more elevated in summer (p<0.05). The values of pH registered in section 02 were slightly more alkaline than in the other sections, and statistic differences among seasons were also observed (p<0.05). The concentrations of dissolved oxygen in water did not differ among sections, but the values observed in summer were significantly smaller (p<0.05). The outflow did not show statistic differences among sections and seasons (p>0.05). observed relationships in The linear regression analysis did not present any relationship between the abundance of eglids and the abiotic parameters, including precipitation (p>0.05). The type of substrate seems to be the principal factor explaining the distribution of this species, as revealed by the values of the linear regression between quantity of rocks and abundance of Aegla sp. n.. (F1,11 = 19.53 p = 0.0016). The size of rocks did not affect the abundance of eglids at the sections sampled. The growth curves of cephalothorax estimated for males and females are described by the following equations: Ct = 28.00 [1 e-0.0047(t+10.63)] and Ct = 25.16 [1 e-0.0051(t+17.65)], respectively. The males were larger than females and the estimated longevity was three years for males and two and half years for females. Differences were observed in the mean and median sizes of the chelipeds, besides a differential growth of the right and left chelae of Aegla sp. n.. The objective of this work was to contribute for the knowledge about some biology aspects of Aegla sp. n.., aiming the conservation of the species. / O objetivo desse trabalho foi avaliar alguns aspectos da biologia de Aegla sp. n.., tais como: tamanho do início da maturidade sexual morfológica, tamanho mediano de machos e fêmeas, distribuição etária, proporção sexual geral e nas classes de tamanho do comprimento cefalotoráxico, período reprodutivo, recrutamento, distribuição espacial, temporal e crescimento em ambiente natural. Este crustáceo é uma espécie nova em processo de descrição. O presente estudo foi realizado no Arroio Passo Taquara, localizado no município de São Pedro do Sul, região central do estado do Rio Grande do Sul. Foram realizadas coletas mensais de maio de 2006 a abril de 2007 em três trechos do referido córrego. Os organismos foram coletados com o auxílio de armadilhas plásticas, sendo que foram dispostas oito por trecho a uma distância de dez metros uma da outra, e com um puçá de 30 x 40 cm de tamanho, fundo de 60 cm e panagem com malha de 0,2 mm, sendo que em cada trecho foi realizado um esforço amostral de 20 minutos por duas pessoas. Os organismos coletados foram sexados com base na presença de pleópodos nas fêmeas e ausência destes nos machos e/ou posição das aberturas genitais (na coxa do 3º par de pereiópodes das fêmeas e 5º par nos machos), quando não era possível a visualização de pleópodos uma lupa foi utilizada para a visualização dos poros genitais. Indivíduos com menos de 3 mm de comprimento cefalotoráxico foram considerados jovens não sexados por não apresentarem pleópodos e poros genitais desenvolvidos o suficiente para a uma visualização com confiabilidade. Os indivíduos tiveram as seguintes dimensões corporais mensuradas com um paquímetro digital com precisão de 0,01mm: Comprimento do cefalotórax (CC - da ponta do rostro até a borda posterior da carapaça), largura do cefalotórax (LC tomada na altura da sutura posterior a região gástrica), largura do segundo somito abdominal (LA), comprimento do própodo quelar esquerdo (CPE), comprimento do própodo quelar direito (CPD) e altura do maior própodo quelar (ALT). Obtidas as medidas e a sexagem, os organismos foram devolvidos no mesmo local de onde coletados. Foram amostrados 916 indivíduos, sendo 17 juvenis não sexados, 601 machos (166 juvenis e 435 adultos) e 298 fêmeas (101 jovens, 172 adultas e 25 ovígeras). O tamanho do início da maturidade sexual morfológica foi estimado, utilizando os programas Mature I e II, em 13,60 e 10,84mm de comprimento cefalotoráxico para machos e fêmeas respectivamente. Machos e fêmeas apresentaram dimorfismo sexual quanto ao seu tamanho mediano. A distribuição em classes de tamanho se mostrou bimodal para machos e fêmeas, o que indica mais de um grupo etário na população. A proporção sexual seguiu o padrão esperado de 1:1, considerando-se os organismos coletados com puçá, fato que não foi observado com o conjunto total dos dados. Foram amostradas fêmeas ovígeras em todas as estações do ano, porém com maior intensidade no inverno, da mesma forma o recrutamento em Aegla sp. n.. apresentou-se de forma contínua ao longo do ano, porém com uma alta intensidade no inverno e primavera. A temperatura da água registrada no Arroio Passo Taquara não apresentou diferenças entre os trechos (p>0,05), porém no verão os valores foram estatisticamente mais elevados (p<0,05). Os valores de pH registrados no trecho 02 foram levemente mais alcalinos que nos demais trechos, da mesma forma foram observadas diferenças nos valores de pH entre as estações do ano (p<0,05). Os teores de oxigênio dissolvido (OD) na água não variaram significativamente entre os trechos (p>0,05), porém os valores de OD foram estatisticamente menores no verão (p<0,05). Não foi observada diferença estatística da vazão entre os trechos e estações do ano (p>0,05). Não foram observados valores significantes na análise de regressão linear entre a abundância de eglídeos e os parâmetros abióticos analisados (p>0,05). Não foi visualizada relação entre a precipitação pluviométrica e a abundância de Aegla sp. n.. no Arroio Passo Taquara (F1,11 = 0,02 p = 0,87). O tipo de substrato parece ser o principal fator que explica a distribuição dessa espécie no Arroio, esse fato fica mais evidente quando observamos o valor da regressão linear entre a quantidade de pedras e a abundância de Aegla sp. n.. (F1,11 = 19,53 p = 0,0016). O tamanho das pedras não se relaciona com a abundância nos três trechos amostrados. As curvas de crescimento do cefalotórax estimadas para machos e fêmeas são descritas pelas seguintes equações Ct = 28,00 [1 e-0,0047(t+10,63)] e Ct = 25,16 [1 e-0,0051(t+17,65)], respectivamente. Os machos atingiram maiores tamanhos que as fêmeas e a longevidade foi estimada em três anos para os machos e dois anos e meio para as fêmeas. Foram verificadas diferenças no tamanho médio e mediano dos quelípodos, além de um crescimento diferencial das quelas direita e esquerda em machos e fêmeas de Aegla sp. n.. O presente estudo busca contribuir para o conhecimento sobre os aspectos da biologia populacional na espécie Aegla sp. n.., visando a criação de medidas conservacionistas.

Many migratory shorebirds rely on estuaries as stop-over sites to refuel during migration, and the loss of stop-over sites is a primary threat to shorebird populations on the West Coast of the United States (e.g. Calidris alpina pacifica, C. mauri). Conservation and research has focused on the largest of these sites; however, smaller estuaries also host thousands of migratory shorebirds. Furthermore, the reasons for site selection are largely unknown. Estuarine inter-tidal microhabitats are non-uniform and both abiotic and biotic factors may serve as predictors of whether an abundance of shorebirds will use a site. I investigated shorebird site selection on broad and fine scales within Oregon estuaries. To identify factors that relate to shorebird abundance on large spatial scales, I compiled shorebird abundance data from estuaries throughout the Pacific Northwest as well as data on site quality factors. To investigate site selection on a finer scale I measured shorebird abundance, habitat characteristics, and food resources―invertebrates and a newly considered source, biofilm―within two Oregon estuaries during the fall migration period. Finally, I examined whether channels are preferentially used by foraging Calidrid shorebirds by conducting observations during the spring migration. I investigated whether channels may be superior foraging habitat possibly because prey are more abundant, are found at shallower depths, or because sediments are more penetrable (increasing the opportunity for shorebird probing) by taking infauna cores and measuring force required to probe in the sediment at channel and open mudflat sites. Among estuaries, shorebird densities in spring were best predicted by estuary size, as opposed to the amount of any one habitat. During fall migration, the amount of grassland in the surrounding watershed was also a good predictor, pointing to the probable importance of roost sites as well as feeding grounds. The amount of infauna also related to the density of shorebirds using a site. Within estuaries, shorebird distribution in the inter-tidal region was not generally predicted by prey abundance. Channels were used preferentially by shorebirds, and infauna abundance along channels was greater than in the surrounding mudflats. The more penetrable sediments of the channel also made it easier for shorebirds to probe and capture prey. Identification of these large-scale and fine-scale factors that influence site quality for migratory shorebirds will assist land and wildlife managers' efforts to protect these species.

No description available.

The use of Habitat Suitability Index (HSI) models for fisheries impact assessment has not been field validated for most fish species. This research sought to test several of the fundamental assumptions inherent in applications of Suitability Index (SI) curves with the Habitat Evaluation Procedures (HEP) of the u.s. Fish and Wildlife Service. Using draft SI's for rock bass (Ambloplites rupestris), tests for positive correlations between standing stocks and measures of fish habitat were conducted in 1982-1983. Multiple regression modeling and analysis of fish production were used to further evaluate the efficacy of habitat assessments for rock bass based on HSI models. Highly significant positive correlations (p<.01, R²=.68) between Habitat Units (HU's) and biomass were observed in Back Creek for November 1982. However, significant positive correlations were not observed consistently for other months, models, or streams evaluated. Factors which apparently accounted for low correlations included seasonal fish movements, fish sampling biases, habitat homogeneity, and the omission of potentially important variables, stitch as depth and cover, from HSI models. Fish production was essentially the same in Little Walker and Back Creeks and averaged 1.04 gm⁻²yr⁻¹. The factors influencing correlations between fish abundance and habitat measurements prevented meaningful comparisons of rock bass production and the related physical habitat. Results from this study suggest that summer low flow periods may not always be most limiting to rock bass habitat in Virginia streams. Furthermore, seasonal movements of fish and sampling biases, if not considered, may seriously confound attempts to relate indices of carrying capacity and habitat model outputs. Incorporating the annual home range of the evaluation species into future study designs is recommended to expedite subsequent attempts to validate HSI models. / M.S.

Virginia is a natural laboratory for studying overwintering habits of the alfalfa weevi1. At higher elevations, winters are relatively harsh and weevil pressure on the alfalfa crop is usually light. Much heavier pressure is the rule at lower elevations where winters are milder. The goal of this study was to examine the effects of fall and winter temperatures, parasites, and fall regrowth management on population dynamics of overwintering stages of this insect. Sixteen commercial alfalfa fields in Montgomery Co. (elevation 610 m) and Bedford Co. (elevation 300 m) were used in the study. Approximately half the fields each year were either harvested or grazed to remove fall regrowth. In the other fields, fall regrowth was left standing through the winter. Six different pitfall trap designs were compared for collection efficiency, installation and servicing effort, and cost. Barrier traps outperformed the other trap designs and were inexpensive and easy to install and service. Sweepnet samples were used to monitor weevil adults during their fall migration. A newly designed sampling device which removes all plant material, litter, and approximately 2 cm of soil from a 1/20 m² area, was used to measure absolute densities during fall and winter. Based on these absolute density samples fewer adults overwintered within fields in which fall regrowth was removed. Dissections revealed the presence of three parasites: Hyalomyodes trianqulifer (Loew), Microctonus aetheopoides Loan, and M. colesi Drea. Total parasitization rates were low. The highest measured rate was 16.1% in Bedford Co. in 1984-85. Female reproductive development also was determined through dissection. Females reach sexual maturity shortly after returning to alfalfa fields in the fall. Most contain full-size eggs in their oviducts from late fall through the winter. Egg densities as measured by laboratory incubation of field collected plant material indicated no differences related to elevation in early February, but significantly more viable eggs were present by late March at the low elevation site. In 1984, Bedford Co. samples indicated significantly more eggs in fields receiving no fall regrowth management. A simulation model called OAWSIM (Overwintering Alfalfa Weevil Simulation) was developed to examine the influence of factors which affect overwintering life stages. Model predictions indicate fall and winter temperatures, and fall regrowth management are major influences on the population dynamics of this insect. / Ph. D.

O presente trabalho tem como objetivo geral o estudo da composição e estrutura da macrofauna bêntica em escala espacial e sazonal, da região de Cabo Frio (RJ). O aspecto temporal nessa área é especialmente importante devido a ocorrência do fenômeno sazonal da ressurgência costeira. Esse ocorre devido alguns fatores físicos característicos da área, tais como mudanças na topografia e na direção da costa, e principalmente, em decorrência das condições meteorológicas atuantes no local. A interação desses fatores favorece, principalmente no verão, o ressurgimento próximo à costa da Água Central do Atlântico Sul (ACAS), uma massa de água fria e rica em nutrientes. Essa massa de água disponibiliza grande quantidade de nutrientes para o fitoplâncton das camadas superficiais, ocasionando uma elevada produção primária nova. Parte dessa produção é exportada para o fundo incrementando a biomassa bêntica. Assim, a comunidade bêntica assume um papel vital no ecossistema, sendo tanto receptora como fornecedora de energia. Os descritores de comunidade (densidade, biomassa, riqueza, diversidade e equitatividade) e a identificação dos grupos tróficos de Polychaeta foram analisados entre 40 e 1000m de profundidade e em três épocas do ano, inverno de 2001 e verão e primavera de 2002. A integração dos dados biológicos com os ambientais mostrou que as variações espaciais na estrutura e composição dos organismos foi relacionada à profundidade e ao tipo de sedimento verificado nas estações. A estrutura da comunidade também apresentou variações temporais, especialmente nas estações situadas na plataforma continental, respondendo à entrada de matéria orgânica decorrente do evento de ressurgência. / The main objective of the present study was to evaluate the composition and spatial and seasonal structure of the macrobenthic fauna off Cabo Frio (RJ). The temporal scale was investigated in the light of the seasonal coastal upwelling. This phenomenon occurs due to changes in bottom topography and in the coastline direction, and specially, because of the prevailing seasonal NE winds in the area. The interaction of these factors enables the South Atlantic Central Water (SACW) to rise up and reaches the surface, intensively during the summer months. Large amounts of nutrients are then brought to the euphotic zone, enhancing primary productivity. This high productivity increases food supply for benthic communities by sinking of particulate organic carbon. In this way, the benthic communities are an important link in the ecosystem. The density of organisms, biomass, species richness and evenness and also the trophic group of Polychaeta were analyzed in a depth gradient from 40 to 1000m during the 2001 winter and 2002 summer and spring. Faunal distributional patterns and species composition correlated with environmental variables, especially depth and sediment types. The faunal structure also showed temporal changes along the sample period, especially in the stations located in the continental shelf due to the input of organic matter to the sea floor.