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 “"length-at-age"”.
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Effects of calendar time, temperature and growing degree-day on Pacific Herring (Clupea pallasii) length-at-age
Forage fish species are essential to global marine ecosystems as conduits of energy transfer from low to high trophic levels. Pacific herring (Clupea pallasii) are an important forage fish species in northeast Pacific marine and estuarine ecosystems. Pacific herring length-at-age (LaA, mm) has …
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The efficacy of back calculation methods for determining length at age data and the use of such data to determine growth standards, national growth patterns and recruitment dynamics of roach (Rutilus rutilus (L.)), dace (Leuciscus leuciscus (L.)) and chub (Leuciscus cephalus (L.)) in UK rivers
The use of fish scales to age and back-calculate previous lengths at age and gain age and growth information has long been used as a management tool in fisheries. Calcified structures from fish, including otoliths, fin rays, and vertebrae have been used to gain length at age data. Scales however, …
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TROPHIC ECOLOGY OF JUVENILE LEAN AND SISCOWET LAKE TROUT (SALVELINUS NAMAYCHUSH) FROM U.S. WATERS OF LAKE SUPERIOR
<p>In this study, I investigated the spatial overlap, diet similarity, and isotopic niches of juvenile Lean and Siscowet Lake Trout ecotypes across six ecoregions of Lake Superior. Spatially, Lean and Siscowet were observed in overlapping depth distributions. Leans were most abundant in shallow …
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Growth and Reproduction of Southern Flounder (<i>Paralichthys lethostigma</i>) in the North-Central Gulf of Mexico
… is the most commonly harvested flatfish in the north-central Gulf of Mexico (GOM) and supports a major inshore recreational fishery, yet knowledge of the species’ life history is greatly limited. The objective of this research was to describe the growth and reproduction of Southern …
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The Evolutionary Effects of Fishing: Implications for Stock Management and Rebuilding
Recent empirical studies have demonstrated inter-generational morphological and life-history changes in fish stocks that have been impacted by size-selective harvest. Evolutionary processes in biological populations occur through differential survival and reproductive success based, in part, upon …
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A study of the river redhorse, Moxostoma carinatum (Pisces; Catostomidae), in the tributaries of the Ottawa River, near Canada's National Capital and in a tributary of Lake Ontario, the Grand River, near Cayuga, Ontario.
This study provides baseline data on the River Redhorse (Moxostoma carinatum; Moxostomatini: Catostomidae) in Canada. Sampling focussed on the Mississippi and Gatineau Rivers, in the National Capital Region, in 1998 and 1999. Spawning occurred in rocky, shallow (<2m) fast-water sections in May …
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Fishery and Population Dynamics of Mississippi’s Spotted Seatrout
<p>Spotted Seatrout (<em>Cynoscion nebulosus</em>) is the most popular recreational inshore fishery in Mississippi coastal waters. Because of the popularity of Spotted Seatrout in Mississippi as a recreational target and the magnitude of harvest, quantitative approaches to describe the population …
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Food Habits of Yellow Perch in Eastern South Dakota Glacial Lakes
… Yellow perch food habits were documented and related to population form and function characteristics. A wide range of yellow perch population types were identified. Higher-quality yellow perch populations were characterized by fast growth, low density, and low and inconsistent recruitment. …
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Spatiotemporal trends and relationships in the abundance, growth, and condition of common nearshore fishes of southwest Lake Michigan
The Laurentian Great Lakes are large, diverse, and dynamic ecosystems whose biotic communities have undergone significant alteration over the last two centuries due to various effects of human habitation in the basin. Currently, the most noticeable effects are those wrought by numerous invasive …
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Reassessment of the Red Drum Stock in Mississippi Coastal Waters: The Role of Ages 3-5 Year-Class Fish
<p>Red Drum, <em>Sciaenops ocellatus</em>, are highly sought after by sport fishermen in Mississippi coastal waters. In 2016, Mississippi anglers made over 180,000 fishing trips targeting Red Drum, making it the second most targeted marine species. The current Fishery Management Plan of the Gulf of …
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Population biology, dynamics and their implications for management of red bass: a large, long-lived reef fish
… (Forsskal 1775), is a large tropical reef fish that has a widespread circum-tropical distribution (Allen 1985). Preliminary research (Marriott 2002) done prior to this thesis identified that this species was potentially long-lived and slow-growing. Knowing this, the harvest of L. bohar by …
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Comparison of Creel Survey Data to Traditional Sampling Techniques in Pit-Lake Fisheries of Muhlenberg County, Kentucky
<p>Populations of largemouth bass, <em>Micropterus salmoides</em>, and bluegill, <em>Lepomis macrochirus</em>, were evaluated from five pit-lakes in Muhlenberg County, Kentucky, to determine if accurate proportional stock density (PSD) data can be obtained from a mandatory creel survey. It was …
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Life-History Characteristics and Fishery Dynamics of Red Drum (<i>Sciaenops ocellatus</i>), in the North-Central Gulf of Mexico
<p>Red Drum (<em>Sciaenops ocellatus</em>) are highly targeted recreationally in the Gulf of Mexico, and support a small commercial fishery in Mississippi. Despite their popularity, the stock is assessed using data limited approaches that necessitate accurate life history information. I estimated …
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Growth and Reproduction of Atlantic Chub Mackerel (<i>Scomber colias</i>) in the Northwest Atlantic
<p>Recent efforts to manage Atlantic Chub Mackerel (<em>Scomber colias</em>) in the northwest Atlantic have necessitated the description of the stocks life-history characteristics. The purpose of this study was to address the absence of regional information on growth and reproduction. Growth models …
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Genetic and Life History Characteristics of Venustaconcha Ellipsiformis and Venustaconcha Pleasii (Bivalvia, Unionidae) in the Ozark Plateaus Region
… characteristics were compared among 7 populations of two closely related taxa of freshwater mussels in river systems of the Ozark Plateaus. Venustaconcha pleasii (White River system) exhibited fixed electrophoretic allelic differences from V. ellipsiformis (Osage and Meramec basins) at 3 of …
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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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Assessment of the Response of Piscivorous Sportfishes to the Establishment of Gizzard Shad in Claytor Lake, Virginia
… illegally introduced to Claytor Lake in the late 1980s and soon established a thriving population. This study assessed 1) the degree to which gizzard shad were utilized by piscivores (pelagic - striped bass Morone saxatilis, hybrid striped bass M. chrysops x M. saxatilis, and walleye …
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Do size differences of juvenile snapper (Pagrus auratus) in two regions of Shark Bay, Western Australia, reflect different environmental conditions
Aspects of the population biology of juvenile Pagrus auratus in the western gulf of Shark Bay, Western Australia, were investigated to explore the causes of an observed size difference between 0+ fish (first year of life) in the northern and southern regions of that gulf. Five trawl surveys were …
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Applications of fish scale analysis to understand growth dynamics of fish populations
… of hard structures to derive ecological information about fish populations is a fundamental tool in fisheries assessment, specifically the back-calculation of fish lengths. This study highlights the potential errors associated with correction factors (c) because of poor sampling and provides a …
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Assessment of Age, Diet, and Growth of Yellow Perch ( Perca flavescens) in Cheat Lake, West Virginia
This thesis evaluates population characteristics of yellow perch ( Perca flavescens) in Cheat Lake, West Virginia, and is comprised of two chapters: 1) an introduction and literature review on the biology, ecology, and life history of yellow perch and studies regarding diet growth, and condition …
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