Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"natural mortality"”.
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Impact of Natural Mortality Factors on Populations of the European Corn Borer in Bt- and Non-Bt-Corn Fields in Illinois
… were conducted to evaluate the incidence of natural enemies of European corn borer in Bt cornfields. The findings were compared with assessments of the effects of natural enemies in non-Bt cornfields. In my study, corn type did not seem to affect the percentage of eggs parasitized by …
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Estimability of natural mortality within a statistical catch-at-age model: a framework and simulation study based on Gulf of Mexico red snapper
Estimation of natural mortality within statistical catch-at-age models has been relatively unsuccessful and is uncommon within stock assessments. The models I created estimated population-dynamics parameters, including natural mortality, through Metropolis-Hastings algorithms from Gulf of Mexico …
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An intensive study of movement and population dynamics in Triakis megalopterus in the De Hoop Marine Protected Area, South Africa
… typically includes managing the fishing mortality and providing marine protected areas (MPAs) as refugia. To this effect, estimating natural mortality rates and home range size is vital. Triakis megalopterus, a commonly caught, endemic coastal shark of South Africa provides an excellent …
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ESTIMATION OF MORTALITY RATES FOR THE GULF MENHADEN STOCK AND REFERENCE POINT IMPLEMENTATION FOR THE FISHERY
… I performed two studies. I first addressed the natural mortality rates currently used in the Gulf menhaden stock assessment. To update these rates, I used data from a tagging study conducted from 1970 to 1988. Adult and juvenile menhaden were tagged, released, and recovered in fish processing …
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Exploring spatial heterogeneity of CPUE year trend and nonstationarity in fisheries stock assessment, an example based on Atlantic Weakfish (Cynoscion regalis)
… and explore the influence of nonstationary natural mortality on the fisheries management through a MSE (Management Strategy Evaluation) algorithm based on the Weakfish stock assessment results. Five models for catch rate standardization were constructed based on the NEAMAP (NorthEast Area …
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Bayesian population dynamics modeling to guide population restoration and recovery of endangered mussels in the Clinch River, Tennessee and Virginia
… were assumed in model estimations: (1) constant natural mortality; (2) one constant natural mortality rate for young mussels and another one for adult mussels; (3) age-specific natural mortality. A Bayesian approach was used to analyze the age-structured models and a Bayesian model averaging …
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Status of Paddlefish in Lake Francis Case, South Dakota
… but this fishery was closed due to a lack of natural recruitment. Lake Francis Case has been stocked intermittently since 1974, and annually since 1990 to maintain a broodstock population and potentially support a sport fishery. Currently, information necessary for effective management of this …
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Growth and Yield-Per-Recruit Modeling of Spot (<i>Leiostomus xanthurus</i>) in the Chesapeake Bay, and a Comparison of Biological Reference Points
… spot. It was determined that spot have a high natural mortality rate (M = 0.9) and fast growth (K = 0.6). This combination of M and K makes spot relatively impervious to growth overfishing as determined by yield-per-recruit modeling. Because spot are nearly impervious to growth overfishing, …
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Estimates of numbers of White sharks (Carcharodon carcharias) in Eastern and Southern South Africa : a post-moratorium assessment
… model indicate that the instantaneous fishing mortality rate F of 0.035 year-l or less allows the population to increase in numbers from 2004 to 2050. A sensitivity analysis determined that the instantaneous natural mortality rate M (tested range=0.070-0.l90 year-I) and the average number of …
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Evaluation of Methodology Use to Estimate Population Size, Sex and Age Ratios, and Mortality of White-tailed and Mule Deer in the Missouri River Breaks Region of South Dakota
… population size, sex and age ratios, and mortality of white-tailed (Odocoileus virginianus) and mule deer (0. hemionus) were evaluated on the= Lower Brule Sioux Reservation, South Dakota. Thirty-three white-tailed and 19 mule deer were radio-collared from 1997-1999 to assess visibility …
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Reproductive biology of female spiny lobster Palinurus Delagoae in two areas off eastern South Africa
… of the growth rate, size at sex maturity and natural mortality of P. delagoae were performed in 2000 (Groeneveld et al) and can be supplemented by the results of this study, which assess the reproductive biology of the East Coast spiny lobster in order to address this aim. A recent study …
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A computer simulation of the population dynamics of the Cape hakes (Merluccius capensis and M. paradoxus)
… was made of two methods of estimating natural mortality (M), utilizing the results of Virtual Population Analysis (V.P.A.). In both cases the criteria used to judge M were found to be insensitive, and therefore neither can be used. 4. The stock estimates obtained using V.P.A. were …
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Aspects of Hylotrupes bajulus (L.) biology in Virginia (Coleoptera: Cerambycidae)
… larvae indicate that H. bajulus can live under natural conditions in Virginia's varied climatic regions. Over the course of two years 27 adults have been collected in such field conditions as fence posts, outhouses, screen windows, building exteriors, and free flying in open fields. This …
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Modelagem matemática do crescimento somático e mortalidade do ouriço-do-mar Cassidulus mitis Krau, 1954 (Echinoidea: Cassidulidae)
… and logistic models), and to estimate the natural mortality of this C. mitis population. The evaluation of the models was accomplished by (1) the analysis of the sum of the square residuals from the former non-linear regressions, (2) the analysis of the distribution of these residuals and …
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Quantification of Variability, Abundance, and Mortality of Maumee River Larval Walleye (Sander vitreus) Using Bayesian Hierarchical Models
… variable; however estimates of abundance and mortality are important in understanding anthropogenic impacts on this spawning group and their role in Lake Erie walleye recruitment. Bayesian hierarchical models were used to quantify spatial and temporal variability, and estimate abundance and …
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Growth and mortality of buka fish, lates stappersii (boulenger, 1914) in the southern part of lake Tanganyika, Zambia.
Population growth parameters and mortality rates of Lates stappersii were investigated for the southeast and southwest arms of Lake Tanganyika, Zambia from April, 2022 to August, 2022. Exploitation ratio was studied. Furthermore, water quality parameters were investigated. Fish samples were …
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Growth and mortality of buka fish, lates stappersii (boulenger, 1914) in the southern part of lake Tanganyika, Zambia.
Population growth parameters and mortality rates of Lates stappersii were investigated for the southeast and southwest arms of Lake Tanganyika, Zambia from April, 2022 to August, 2022. Exploitation ratio was studied. Furthermore, water quality parameters were investigated. Fish samples were …
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Making kin : landscape, material and senses
… separations has gradually decreased through natural mortality, with only about 16 percent of those aged 80 or younger remaining as witnesses. In the next decade the memories of family ties across the DMZ may be lost forever. Very recently, in April 2019, the governments of North and South …
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An evaluation of harvest, survival, growth, and movement of five strains of rainbow trout (Salmo gairdneri) in Virginia Streams
… during April was not evident in fished streams. Natural mortality rates in the reference stream did not differ significantly among strains between May 20 and October 22, 1981. Change in average length of the strains over four months in Spring Branch ranged from -4.3 mm for EN to +18.9 mm for SW. …
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