Thesis (M.S.)--Brigham Young University. Dept. of Plant and Animal Sciences, 2007. / Includes bibliographical references (p. 38-40).

In Sweden, the Wels catfish (Silurus glanis) is a protected species and exist in only three known water systems in the country. With spawning habitats being destroyed by human activities, it is important to know more about the Swedish catfish’s reproductive behaviour and habitat preferences in order to protect the species. In this report, catfishes tagged with transmitters was tracked using radio telemetry, day and night for two weeks in Lake Båven during the spawning period. Habitat data on the depth, bottom hardness and vegetation was collected in known and potential spawning areas in the lake using an echo sounder. Habitat preference analysis indicated depth and bottom hardness as important factors when catfishes chose spawning habitat.  The analysis did not indicate vegetation to be important. Habitat data from spawning positions of tagged catfishes was used to identify other sites suitable for reproduction in nearby areas. Home range during spawning was calculated for two catfishes and was found to be 1.05 and 1.35 ha. Based on this information and the identified sites suitable for spawning, the total available spawning habitat in the study area was found to be enough for 12 to 15 catfishes. This is relatively few, and indicates that additional spawning sites would benefit the population.

No description available.

No description available.

The primary objectives of this study were: 1) to evaluate the movement patterns, habitat use, and survival of triploid grass carp Ctenopharyngodon idella stocked to control hydrilla Hydrilla verticillata in a riverine reservoir (Claytor Lake, Virginia), 2) to examine grass carp population dynamics and hydrilla growth dynamics in Claytor Lake to guide long-term management efforts, and 3) to describe the aquatic plant community in the New River upstream of Claytor Lake to assess the potential for alterations due to potential grass carp herbivory. Only 3% of radio-tagged grass migrated out of Claytor Lake during the 2-year study. Grass carp movement patterns were significantly correlated with temperature-, weather-, and habitat-related variables. Grass carp selected specific cove, shoal and tributary habitats colonized by hydrilla. First-year survival of grass carp was 44% in 2011, and 25% in 2012. Grass carp growth rates were rapid in 2011, but declined in 2012 concurrent with significant reductions in hydrilla abundance. Based on grass carp population dynamics observed in Claytor Lake, our stocking model predicted that hydrilla could be controlled through 2030 by a grass carp standing stock of 5-6 metric tons. We documented 12 plant species in the New River upstream of Claytor Lake, 9 of which are preferred plants for grass carp suggesting that the plant community could be altered if migration rates increase. Grass carp can be effective for managing hydrilla in riverine reservoirs; however, continued monitoring of grass carp population dynamics, migration rates, and vegetation abundance could facilitate greater precision in management efforts. / Master of Science

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / The basic concepts of wide band mobile ad hoc networking are used in this thesis to extend the functionality of a typical low-speed telemetry system. Although most efforts related to wireless networking are driven by the insatiable demand for high-speed mobile data applications, telemetry applications ensure the continuous wide spread use of lowspeed narrow band data networks. A multi-hop auto-routing telemetry system has the advantages of extended operational range, and portability, for nomadic monitoring, or rapid deployment applications. All stations operate both in their telemetry capacities, providing typical functionality and I/O capabilities, as well as implicit routers, supporting a DSR based protocol to achieve dynamic, multi-hop operation. While the emphasis of work described in the thesis is placed on the optimal design and development of a dynamic, multi-hop telemetry network, a further aspect presented herein is the extension of an existing state transition matrix queuing model to encompass the type of network designed. The model offers a prediction of latency performance of the multi-hop system using half duplex low speed radio links, and corresponds with measured results.

Migratory birds, some small and light weight as matchboxes, engage in seasonal inter-continental journeys in order to take advantage of the long summer days and abundance of food at northern latitudes to breed and raise their young, and then escape the harsh winters by migrating to lower latitudes. This thesis deals with two important aspects of migration, the routes taken during migration and the birds’ behaviour at stopovers. The migratory routes are for many species unknown, whole or in part, and this is especially true for species that migrate nocturnally. At stopovers birds replenish fuel reserves that powers migratory flight, and studying how birds utilise stopovers is important in order to understand how migration is organised. In this thesis I have used modern tracking technology to study both continental wide movements of thrush nightingales (Luscinia luscinia) and common rosefinches (Carpodacus erythrinus) using small light-level geolocators, and smaller scale movements at a single stopover site of garden warblers (Sylvia borin) using miniature radio-transmitters. I have also studied the fuelling behaviour of garden warblers during autumn migration in the field and in the lab, and great reed warblers (Acrocephalus arundinaceus) at a stopover site on Crete during spring migration after the Sahara crossing. The thesis discusses the significance of several aspects of migration shown by the birds that would have been very difficult to detect without the aid of modern tracking technology, such as loop migration, prolonged stops during migration, multiple wintering sites, and nocturnal relocations at stopover sites. Studies carried out at stopover sites also show that garden warblers and great reed warblers can attain large fuel loads even at sites where they have no barrier to cross and this might be a result of good foraging conditions. The thesis also highlights the importance of combining different techniques when studying stopover behaviour to get reliable estimates on stopover durations and fuel deposition rates as well as the importance of choosing sites preferred by birds when planning stopover studies. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.</p>

Thesis (Ocean E)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Carl Alzen Wales. / Ocean E

Os eglídeos (Anomura, Aeglidae) são um grupo de crustáceos endêmicos do sul da América do Sul e restritos ao ambiente de água doce. Muitos aspectos da biologia e ecologia desses animais são bem conhecidos, porém, pouco se sabe sobre seu comportamento, principalmente o comportamento agressivo e a atividade em ambiente natural. É sabido que entre os animais, os conflitos são resolvidos por comportamentos agonísticos, termo que abrange uma gama de comportamentos de escape, exibições (“displays”), até um extremo do combate físico. Em um contexto ecológico, informações sobre os movimentos e a atividade dos animais são importantes para uma compreensão das exigências de hábitat, padrões de utilização dos recursos e o potencial de interações interespecíficas. A presente tese teve como objetivos: padronizar uma metodologia para análise do comportamento agressivo de eglídeos em laboratório; descrever o comportamento agressivo de Aegla longirostri; avaliar o comportamento agonístico de espécies provenientes de vertentes do lado Pacífico (espécies basais) e Atlântico (espécies derivadas) da América do Sul; comparar os padrões agressivos de fêmeas de A. longirostri e A. manuinflata, e; examinar os padrões de deslocamento, de atividade diária e de ocupação dos diferentes substratos por A. manuinflata em ambiente natural. Para os estudos sobre comportamento agressivo, os animais coletados foram mantidos em aclimatação por uma semana em aquários individuais, pareados para realização de interações intra-específicas e filmados durante 20 minutos, período que foi subdivido para realização das análises. A parir dos confrontos com A. longirostri foram descritos os atos comportamentais, com 16 atos agressivos, e foi estabelecida uma tabela de intensidade da agressividade, variando de -2 (fuga) a 5 (combate intenso). No estudo comparativo entre quatro espécies de Aegla, foi verificado que todas apresentaram comportamentos semelhantes, porém um indivíduo de Aegla denticulata denticulata, apresentou tanatose. O período de latência foi superior ao tempo investido em todos os encontros agressivos. Aegla longirostri, a espécie mais derivada (da vertente do Atlântico) foi a que apresentou maior intensidade agressiva média e a mais basal (da vertente do Pacífico), A. d. denticulata a menor intensidade. Aegla abtao, A. longirostri e A. manuinflata gastaram significativamente mais tempo lutando, prendendo ou agarrando o oponente do que os demais atos, enquanto A. d. denticulata passou 18,2% do tempo sem deslocamento, e não apresentou confronto intenso. Em todas as espécies foi verificada reversão da dominância. Entre as fêmeas, o comportamento é semelhante àquele observado nos machos das mesmas espécies. O período de latência foi mais longo do que qualquer encontro, e o primeiro foi em média mais longo que os demais. Houve uma baixa freqüência na reversão da dominância, o animal que venceu o primeiro encontro, conseqüentemente teve uma probabilidade maior de ser o vencedor final. Para ambas as espécies, o ato mais freqüente foi o de lutar e/ou prender e agarrar com o quelípodo, seguido pelo uso das antenas. A agressividade das fêmeas pode chegar a altos níveis, por vezes, superando a agressividade observada em machos. Para avaliar o deslocamento e a atividade de A. manuinflata em ambiente natural, machos adultos e em intermuda foram monitorados a cada três horas durante nove dias, através da técnica de rádio-telemetria. Os eglídeos apresentaram um deslocamento significativamente maior à montante e apresentaram maior atividade de deslocamento na fotofase escura; a atividade locomotora não foi constante, sendo verificado que os animais passaram um ou mais dias sem deslocamento. Os indivíduos apresentaram especificidade em relação à ocupação dos diferentes tipos de substrato. Esses estudos trazem informações inéditas relativas ao comportamento agressivo de eglídeos, o qual é semelhante ao observado em outros decápodos com quelípodos bem desenvolvidos, porém, muitas peculiaridades foram observadas. Além disso, os resultados do estudo de rádio-telemetria forneceram mais uma informação importante para estudos de conservação das espécies, demonstrando a importância da manutenção dos ambientes naturais para esses indivíduos. / The aeglids (Anomura, Aeglidae) are endemic crustaceans from south region of South America and restricted to freshwater environments. Although several biological and ecological aspects of these animals has already been studied little is known about their behavior, mainly its aggressive behavior and activity in the natural environment. It is known that among animals, conflicts are resolved through agonistic behavior, an expression of which embraces a range of fleeing behaviors, displays, up to the extreme of physical combat. In an ecological context, information on the movements and activity of animals is important for understanding their requirements of habitat, resource usage patterns and the potential of interspecific interactions. This thesis has the following goals: to standardize a method in order to analyze the aggressive behavior of aeglids in laboratory; to describe the aggressive acts of Aegla longirostri; to evaluate the agonistic behavior of species originated from slopes on the Pacific (basal species) and Atlantic (derived species) sides of South America; to compare aggressive pattern of A. longirostri and A. manuinflata females; and to examine the displacement pattern on daily activity and occupancy of substrates by A. manuinflata in natural environment. For the aggressive behavior studies the animals were kept for one week of acclimation in individual fishbowls, then paired for experiments of intraspecific interactions and videotaped for 20 minutes, period which were subdivided for analyzes. From combats with A. longirostri the behavioral acts were described, 16 were considered aggressive acts, and a table of aggression intensity was established, ranging from -2 (fleeing) to 5 (intense combat). Concerning the comparative study among four species of Aegla it was verified that all of them exhibited similar behaviors, but one individual of Aegla denticulata denticulata displayed thanatosis. The latency period was greater than the time invested in all aggressive encounters. Aegla longirostri, the most derived species (from Atlantic slope), was the species that displayed the highest average aggressive intensity and, the most basal species (from Pacific slope), A. d. denticulata the lowest intensity. Aegla abtao, A. longirostri and A. manuinflata spent significantly more time fighting, holding or catching the opponent than the other acts, while A. d. denticulata spent 18.2% of the time without any displacement and did not exhibit intense combat. Reversal of dominance was observed in all species. Female’s behavior is similar to that observed in conspecific males. The latency period was longest than any other encounter and the first one was in average the longest. There was a low reversal of dominance; the animal which won the first encounter consequently had a higher probability of being the final winner. For both species the most frequent act was fighting and/or holding and catching with the cheliped, following by the use of antennae. Female’s aggressiveness can reach high levels, overcoming sometimes the aggressiveness observed in males. To evaluate the displacement and activity of A. manuinflata in natural environment adult males in intermolt stage were monitored at every three hours during nine days through radio-telemetry technique. The aeglids showed a significantly greater displacement toward upstream and had the highest displacement activity on dark photophase; the locomotor activity was not constant, it was observed that the animals spent one or more days without any displacement. Individuals showed specific occupation of different types of substrate. These studies bring novel information concerning aggressive behavior of aeglids which is similar to the behavior observed in other decapods with developed chelipeds, although several peculiarities were noticed. Besides, the results from the radio-telemetry study provided more important information for conservation studies of species, demonstrating the importance of maintenance of natural environment for these animals.

<p>Many endotherms use torpor on a seasonal or daily basis to conserve metabolic resources during difficult conditions, but the capacity to do so has never been recognized as varying intraspecifically. I hypothesized that populations that are exposed to prolonged cold, snow, or scarcity of food resources relative to other conspecifics may express torpor despite the fact that other conspecifics may not use, or even be capable of, torpor. I studied thermoregulation of black-tailed prairie dogs (<I>Cynomys ludovicianus</I>) and Ords kangaroo rats (<I>Dipodomys ordii</I>) at the extreme northernmost periphery of each species range to determine whether there is evidence for geographic variation in torpor patterns.</p><p>Contrary to previous studies of black-tailed prairie dogs near the centre of the species range, I found that northern prairie dogs hibernate during winter, spending up to 95 days per year in torpor. Synchrony of body temperature patterns of some individuals suggests that northern prairie dogs hibernate communally. Similarly, in contrast to previous studies of kangaroo rats in more southern localities, I found that northern Ords kangaroo rats use daily torpor during winter, entering torpor on up to 70 days per year. Kangaroo rats that use deep torpor exhibit comparable survival and pre-winter body mass, but poorer spring body condition, than kangaroo rats that do not use deep torpor. I reported the details of my procedures for studying thermoregulation of small mammals in the wild, to encourage comparable studies that would provide additional insights on intraspecific variation in torpor patterns. My findings are the first to demonstrate that the capacity for torpor varies predictably on a geographic basis.</p>