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Historic And Anthropogenic Influences On The Genetic Variation Of Lake Trout Salvelinus Namaycush Populations In The Great Lakes Region
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Book Synopsis Historic and Anthropogenic Influences on the Genetic Variation of Lake Trout (Salvelinus Namaycush) Populations in the Great Lakes Region by : Michael A. Halbisen
Download or read book Historic and Anthropogenic Influences on the Genetic Variation of Lake Trout (Salvelinus Namaycush) Populations in the Great Lakes Region written by Michael A. Halbisen and published by . This book was released on 2008 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Genomic Basis for Fitness and Ecomorphological Variation in Recovering Populations of Lake Trout (salvelinus Namaycush) in the Great Lakes by : Seth Robert Smith
Download or read book The Genomic Basis for Fitness and Ecomorphological Variation in Recovering Populations of Lake Trout (salvelinus Namaycush) in the Great Lakes written by Seth Robert Smith and published by . This book was released on 2021 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here I describe the development of novel genomic resources that will be fundamental for advancing a new generation of genomic research on Lake Trout (Salvelinus namaycush) including a high-density linkage map, an annotated chromosome-anchored genome assembly, and three high-throughput genotyping panels. We used these resources to identify genomic regions exhibiting signals of adaptive divergence between Lake Trout hatchery strains, some of which were found to underlie differences in fitness (survival and reproduction) between strains in the contemporary Lake Huron environment. Loci associated with differences in fitness between Seneca and Great Lakes origin strains were localized using local ancestry inference and local ancestry outlier tests. By evaluating locus specific allelic contributions of the ancestral Seneca Lake and Great Lakes-derived hatchery strains to naturally-produced wild Lake Huron populations across the genomes of F2 wild born individuals, we were able to determine that a subset of 7 genomic regions contributed to differences in fitness between Seneca Lake and Great Lakes origin individuals during the re-emergence of wild populations in Lake Huron. We also identified 2 genomic regions where Great Lakes origin alleles were favored by selection, 4 regions associated with hybrid vigor, and 2 regions potentially associated with hybrid inferiority in recovering wild Lake Trout populations. We also found that some Seneca origin alleles are only favored by selection on certain genetic backgrounds. For instance, F2 hybrids between the Seneca strain and Lake Michigan origin strains have an excess of Seneca origin haplotypes on chromosome Sna11, while this is not the case in hybrids between Lake Superior and Seneca origin individuals. Collectively, these results indicate that elevated performance of the Seneca strain can at least be partially attributed to a number of adaptive alleles at a small subset of genes. Additionally, the fact that Great Lakes origin alleles were favored by selection at two loci indicates that native strains contain some variation that provides a fitness advantage in Lake Huron. These admixture outlier regions contained a significant excess of genes related to swimming behavior and negative regulation of vascular wound healing, which strongly suggests that differences in fitness between strains are due to behavioral and physiological factors associated with the ability to avoid and survive predation by Sea Lamprey. Additionally, we carried out two studies seeking to identify genetic variation associated with habitat occupancy and phenotypic variation in Lake Trout. First, we carried out a quantitative trait locus (QTL) mapping study in which we identified loci associated with length and condition related traits, skin pigmentation, and body shape. We produced a linkage map for Lake Trout as a prerequisite for this work. The information on locus order obtained from the linkage map was also critical to the assembly of the Lake Trout genome and recombination rate estimates obtained from the linkage map were critical to the goal of assigning haplotype segments to their hatchery strain of origin for wild-born Lake Huron individuals. This study also allowed us to determine the location of the Lake Trout sex determination locus, determine centromere locations, and characterize structural differences (i.e., chromosomal inversions and translocations) between Lake Trout and other salmonid species. Second, we performed a genome-wide scan for loci associated with ecomorphological divergence in Lake Superior Lake Trout (specifically between lean, siscowet, and humper forms), and identified numerous regions with abnormally high levels of divergence between forms. These loci likely underlie variation in traits that differentiate forms, as well as traits that contributed to reproductive isolation historically. For example, the genomic region most strongly associated with length and condition (from our QTL mapping study) was also associated with ecomorphological divergence in Lake Superior and this region also contains a putative chromosomal inversion. Interestingly, we find that hybridization primarily occurred between humpers and siscowets and humpers and leans immediately preceding a genetic homogenization event that occurred in the late 1990s or early 2000s. Using a collection of samples over a multi-decade time series collected from the Apostle Islands, we show that levels of hybridization with humpers increased substantially starting in the 1980s.
Book Synopsis Patterns and Causes of Life History Variation in Lake Trout, Salvelinus Namaycush by : Jenni L. McDermid
Download or read book Patterns and Causes of Life History Variation in Lake Trout, Salvelinus Namaycush written by Jenni L. McDermid and published by . This book was released on 2007 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lake trout (Salvelinus namaycush) exhibit substantial life history variation across their range, but considerable local variation also occurs. Life history traits play a critical role in shaping population dynamics. As such, the observed life history variation makes it difficult to build conservation and management models. Populations should respond to varied environmental conditions by selecting the most favourable combination of life history traits. However, life history traits may alter as a result of phenotypic plasticity and/or genetic response to environmental conditions. This thesis examines the degree and mechanisms behind life history variation in lake trout. Variability is examined over the species range and within small geographic areas. Results indicate a strong association between enviromnental and lake trout life history variability. In particular, climate variables such as net thermal input and winter length and severity are correlated with a number of lake trout life history characteristics across the range. Lake morphology was associated with asymptotic sizes of lake trout, and shows contrasting associations with longevity and size at maturity in northern versus southern ranges. On a local scale, divergence in life history traits represented a combination of plastic responses and genetic adaptations to local conditions. The majority of life history traits examined in this thesis appeared to have a genetic basis; however stunted populations showed a plastic response to lack of forage fish. Yet, not all stunted populations within a region showed similar adaptive responses in early life history characteristics and we propose that the different responses may be predator mediated. Finally, the phenotypic divergence in life history traits among populations introduced from a common source approximately a century ago exhibited rapid plastic and genetic responses to novel environments. This thesis identifies that both plastic and genetic responses are common in lake trout, that these responses can occur quite rapidly, and that a significant number of environmental variables need to be considered before we can predict life history variation. These findings may be even more critical as populations continue to face stresses from climate change, overexploitation, habitat destruction, and introduced species.
Book Synopsis The Lake Charr Salvelinus namaycush: Biology, Ecology, Distribution, and Management by : Andrew M. Muir
Download or read book The Lake Charr Salvelinus namaycush: Biology, Ecology, Distribution, and Management written by Andrew M. Muir and published by Springer Nature. This book was released on 2021-03-03 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lake charr Salvelinus namaycush is a ubiquitous member of cold-water lake ecosystems in previously glaciated regions of northern continental U.S., Alaska, and Canada that often support important commercial, recreational, and subsistence fisheries. The lake charr differs from other charrs by its large size, longevity, iteroparity, top-predator specialization, reduced sexual dimorphism, prevalence of lacustrine spawning, and use of deepwater habitat. The species is remarkably variable in phenotype, physiology, and life history, some of which is reflected in its ecology and genetics, with as many as four morphs or ecotypes co-occurring in a single lake. The lake charr is often the top predator in these systems, but is highly adaptable trophically, and is frequently planktivorous in small lakes. The lake charr by their name highlights their common habitat, lakes both large and small, but often frequents rivers and occasionally moves into the Arctic Ocean. Movement and behaviour of lake charr are motivated by access to cool, well-oxygenated water, foraging opportunities, predator avoidance, and reproduction. Owing to their broad distribution and trophic level, the lake charr serves as a sentinel of anthropogenic change. This volume will provide an up-to-date summary of what is currently known about lake charr from distribution to genetics to physiology to ecology. The book provides a compilation and synthesis of available information on the lake charr, beginning with an updated distribution and a revised treatment of the paleoecology of the species. Understanding of ecological and genetic diversity and movement and behaviour of the species has advanced remarkably since the last major synthesis on the species over 40 years ago. Mid-sections of the book provide detailed accounts of the biology and life history of the species, and later sections are devoted to threats to conservation and fishery management practices used to ensure sustainability. A new standard lake charr-specific terminology is also presented. The book will be a valuable reference text for biologists around the world, ecologists, and fishery managers, and of interest to the angling public.
Book Synopsis An Analysis of Genetic Variation Among Lake Trout (Salvelinus Namaycush) Populations by : Terrence R. Dehring
Download or read book An Analysis of Genetic Variation Among Lake Trout (Salvelinus Namaycush) Populations written by Terrence R. Dehring and published by . This book was released on 1981 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Population Differentiation of Ontario Lake Trout (Salvelinus Namaycush) Using the Major Histocompatibility Complex Class Ii [beta] Gene by : Steven Kuntz
Download or read book Population Differentiation of Ontario Lake Trout (Salvelinus Namaycush) Using the Major Histocompatibility Complex Class Ii [beta] Gene written by Steven Kuntz and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The lake trout (Salvelinus namaycush) is a coldwater salmonid with an extensive native distribution across formerly glaciated regions of North America. Lake trout are known to be a glacial 'relict' species and evolved as a result of glaciation events during the Pleistocene era. Historic and recent human activities along with climate change have had a significant influence on the phylogeographic and genetic compositions of current lake trout populations. Human activities like overexploitation, habitat degradation and most importantly stocking have had detrimental effects on the diversity and variability of populations within Ontario. Prior genetic studies of lake trout have used multiple neutral genetic marker systems including allozymes, microsatellites and mitochondrial DNA (mtDNA) to distinguish multiple glacial refugia and phylogeographic lineages within North America. This project differentiated lake trout populations within Ontario using a non-neutral marker, the major histocompatibility (MH) class II beta gene. A total of fifty-seven unique MH class II [beta]1 alleles were identified in 216 individual lake trout from ten lakes across Ontario and one in New York. Native, hatchery stocking sources and native but stocked lake trout populations were characterized for MH diversity and allelic states to assess their diversity and divergence. A geographic map of MH diversity within each lake was completed. Commonly stocked lakes within Ontario have shown a decreased amount of allelic diversity when compared to other populations. The introgression of MH class II beta alleles within the mixed-ancestry populations and the significance of adaptive genetic diversity within and among populations from different histories will be important for the management of lake trout facing future climatic and ecological conditions.
Book Synopsis Genetic Diversity and Interrelationships of Wild and Hatchery Lake Trout in the Upper Great Lakes by : Kevin Scott Page
Download or read book Genetic Diversity and Interrelationships of Wild and Hatchery Lake Trout in the Upper Great Lakes written by Kevin Scott Page and published by . This book was released on 2001 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spatial and Thermal Ecology of Lake Trout (salvelinus Namaycush) in Lake Erie by : Tyler R. Funnell
Download or read book Spatial and Thermal Ecology of Lake Trout (salvelinus Namaycush) in Lake Erie written by Tyler R. Funnell and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rehabilitation of lake trout (Salvelinus namaycush), which historically was the coldwater apex predator of much of the Laurentian Great Lakes, is a priority for fishery management agencies in the region. In Lake Erie, the shallowest and southern-most Great Lake, successful rehabilitation of lake trout has been hindered by limited wild recruitment, possibly related to the lake's warm temperatures and restricted oxythermal habitat. I used acoustic telemetry tracking technology to investigate how lake trout spatial and thermal habitat use varies seasonally in Lake Erie to better understand whether limited recruitment could be caused by thermal conditions in the lake. As expected, lake trout were restricted to the offshore region of the eastern basin of Lake Erie during summer stratification. During fall, lake trout tended to occupy the southern nearshore region of the eastern basin, suggesting the importance of focusing spawning habitat restoration in this part of the lake. Tagged fish dispersed long distances at much higher frequencies than other Great Lakes populations of lake trout. Lake trout in Lake Erie occupied thermal habitat similar to other Great Lakes populations during summer stratification. Following destratification in fall, fish were exposed to warm temperatures, in some years for extended periods. Lake trout hatchery strains of Finger Lakes, NY, origin occupied similar summer temperatures and warm temperatures for more days during fall than Great Lakes origin strains, contrary to findings from Lakes Huron and Ontario. These results reveal behaviors that can inform management of lake trout in Lake Erie and throughout the Great Lakes and could begin to explain recruitment failure observed in Lake Erie.
Download or read book Proceedings written by and published by . This book was released on 2002 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Lake Trout Restoration in the Great Lakes by : Kelley Salvesen
Download or read book Lake Trout Restoration in the Great Lakes written by Kelley Salvesen and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lake trout populations in the Great Lakes began to decline in the late 1800's as a result of overexploitation, sea lamprey predation and habitat degradation. This decline continued into the 1950's, when lake trout were thought to be completely extirpated from the Great Lakes, with the exception of Lake Superior and limited areas of Lake Huron. Stocking of lake trout began in the 1960's in an effort to restore naturally reproducing populations, with stocking relying on remnant lake trout populations as source populations. These source populations from the Great Lakes, the Finger Lakes, and from introduced populations in the western United States provided the ability to produce numerous hatchery strains. Historically, multiple lake trout strains were stocked in various locations throughout the Great Lakes with the intent that natural selection would allow for survival of the strain best suited to each specific habitat. However, stocking has not yet achieved intended recovery targets of restoring basin-wide natural reproduction, and so hatchery supplementation continues. In an effort to further lake trout restoration goals throughout the Great Lakes, this study had three components: (1) evaluate the efficacy of hormone manipulation to increase hatchery production of the Klondike strain (2) quantify the current genetic status of hatchery strains in production; (3) identify hatchery strain of origin for lake trout reproducing in the Niagara River, NY, as well as their offspring, and to quantify adult lake trout movement into and out of the Niagara River.The Klondike strain of lake trout is a humper morphotype native to Lake Superior and the production of broodstock is maintained at Iron River National Fish Hatchery in Iron River, WI. The Klondike strain has very poor eye-up rates compared to other hatchery strains raised in similar conditions (3-33% eye-up rates, compared to >70% of many lean morphotypes). Based on previous studies analyzing potential health and environmental changes possible in a hatchery setting, induction of spawning through the use of gonadotrophin releasing hormone analogues (GnRHa) was explored as a possible hatchery management tool for increasing eye-up rates. The experimental design consisted of two treatment groups of fish (low dose of 10ug/kg body weight and high dose of 20ug/kg bw) and a control group (saline solution injection). Other lake trout, not used in the experiment, but raised in a similar hatchery setting were used for further comparison (i.e., these "baseline" fish were not handled because they did not receive hormone or saline injections). Both the low and high dose injection of GnRHa resulted in similar increases in eye-up rates compared to control fish (~62%) and baseline non-study fish (>98%). Interestingly, the control injection of saline solution also had higher eye-up rates when compared to the baseline group of fish (84% compared to >98% in treatment groups). Beyond an increase in eye-up rates, fish treated with hormones also had a higher number of viable eggs per fish than baseline fish. While this study had some confounding factors that made results for saline-injected control fish difficult to interpret (i.e., hormone injected and control fish were held in the same holding tanks), hormone injection did improve eye-up rates. This improvement in eye-up rate allows the hatchery to produce a greater number of fry, while still maintaining the same number of broodstock fish. Because the Klondike is the only strain of the humper morphotype currently in the federal hatchery system, increased production could result in reaching targeted stocking rates, and possibly allow for increased stocking or stocking in new locations.Currently, there are six different hatchery strains of lake trout in production in the federal hatchery system. These strains each represent a sample of six different lake trout populations and are used to assist in the restoration goal of establishing naturally reproducing lake trout populations throughout the Great Lakes. Because these strains are a sub-sample of the source population, genetic diversity can become limited if not properly monitored. This can be detrimental to establishment of or developing populations, if stocked fry are inbred, genetically similar, or somehow have reduced survival due to lack of genetic diversity. To understand the current status of lake trout hatchery strains, fin clips were taken from at least two different year classes of each strain for genetic analysis (only one year class was available for the Lake Champlain strain; three were available for the Seneca Lake strain). For the Klondike strain, a sample of the source population was available and used for comparison. Using a suite of eleven microsatellite loci, each strain was assessed for genetic diversity. All hatchery strains were found to have similar levels of genetic diversity, even though all are genetically distinct from one another. The Klondike strain, however, showed evidence of loss of genetic diversity, specifically allelic richness, when compared to the wild source population. Continued monitoring of the genetic diversity of the Klondike hatchery strain would be beneficial.Based on sampling by the U.S. Fish and Wildlife Service and anecdotal evidence from recreational fishermen, a naturally reproducing population of lake trout appeared to be using the lower Niagara River for spawning. To better understand movement of this population and to provide further evidence of natural reproduction, fish were captured in the fall 2010 and 2011 before spawning began and implanted with radio transmitters. Tissue samples were also taken to assess hatchery strain of origin of all adults captured. Sampling for naturally reproduced offspring took place in the fall using egg traps, as well as in the spring using nets. Naturally reproduced offspring were genetically sequenced to determine species before microsatellite markers were used to identify hatchery strain of origin. Identical microsatellite protocols were used on adult samples to determine hatchery strain of origin. The majority (86%) of lake trout sampled during this study, adult and offspring, were assigned to the Seneca Lake strain. While radio transmitters were deployed, the data gathered was insufficient for statistical modeling. Based on the findings from this study, the majority of natural reproduction occurring in the lower Niagara River is by stocked lake trout of the Seneca Lake strain.
Book Synopsis Canadian Journal of Fisheries and Aquatic Sciences by :
Download or read book Canadian Journal of Fisheries and Aquatic Sciences written by and published by . This book was released on 1998 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Life History Parameters of Great Lakes Populations of Lake Trout, Lake Whitefish, Bloater, Walleye, and Yellow Perch by : Cindy Chu
Download or read book Life History Parameters of Great Lakes Populations of Lake Trout, Lake Whitefish, Bloater, Walleye, and Yellow Perch written by Cindy Chu and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Life history parameters summarize the growth, maturity and mortality of populations. This report describes the data used to calculate the life history parameters of 12 lean and 6 siscowet lake trout (Salvelinus namaycush), 26 lake whitefish (Coregonus clupeaformis), 8 bloater (Coregonus hoyi), 9 walleye (Sander vitreus) and 12 yellow perch (Perca flavescens) populations in the Great Lakes. Interpopulation (among populations), intrapopulation (within populations through time) and virtual population analysis results are summarized in this report. These estimates of life history parameters can be used to inform fisheries management and ecological modelling.
Book Synopsis Boreal Shield Watersheds by : John Gunn
Download or read book Boreal Shield Watersheds written by John Gunn and published by CRC Press. This book was released on 2003-08-27 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boreal Shield Watersheds: Lake Trout Ecosystems in a Changing Environment brings together the work of a renowned international group of scientists who specialize in aquatic science and environmental management. They explore the functioning of Boreal Shield ecosystems, focusing on the lake trout, the classic coldwater species of northern glaciated l
Book Synopsis ANTHROPOGENIC INFLUENCES ON THE DECLINE, RESTORATION, AND ECO-EVOLUTIONARY DYNAMICS OF LAKE SUPERIOR'S COASTER BROOK TROUT by :
Download or read book ANTHROPOGENIC INFLUENCES ON THE DECLINE, RESTORATION, AND ECO-EVOLUTIONARY DYNAMICS OF LAKE SUPERIOR'S COASTER BROOK TROUT written by and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : The coaster brook trout is a life history variant of the brook trout (Salvelinus fontinalis) that is characterized by either lake residency or migration between stream and lake habitats. Coaster brook trout were once widespread throughout Lake Superior and its tributaries, but populations declined sharply in the late 19th and early 20th centuries. Historically, brook trout were a popular target of recreational and subsistence fishing in the Lake Superior basin, and it has been hypothesized that angling pressure combined with multiple forms of industrial development are what drove the coaster brook trout's decline. In the mid to late 19th century, the logging, lumbering, and mining industries proliferated rapidly, along with the network of railroads, which provided connectivity for industry and access to once remote fishing locations. However, it is unknown to what degree each of the proposed factors influenced the coaster's decline. In Chapter 1, we collected and analyzed historical data (Pre 1880-1950) on the distribution & abundance of brook trout in Lake Superior tributaries, along with historical data on the development and expansion of industries around Lake Superior to examine potential associations between specific anthropogenic impacts and coaster brook trout declines. The data were separated into four temporal categories (Pre 1880-1880, 1881-1900, 1901-1920, 1921-1950) to examine reports of brook trout catches during critical time periods in industrial developments around Lake Superior. We performed a geospatial analysis using ArcGIS Pro that demonstrated a decrease in both putative coaster brook trout abundance and range over time. Brook trout decreased notably between the '1881-1900' time period and the '1901-1920' time period, following large increases in both lumber mills and kilometers of railroad. We performed a principal component analysis to reveal potential associations between variation in industrial variables and brook trout abundances in watersheds between the first and final time periods (Pre 1880-1880 & 1921-1950, respectively). Our analysis showed that the majority of watersheds analyzed experienced a decrease in brook trout abundance and suggested that the industrial development variables we examined all are associated with and thus may have all influenced brook trout decline, though to varying degrees, as some developments were highly localized. Angling appears to be an important factor in the decline of brook trout populations around Lake Superior, as active angling (noted removals of brook trout) occurred in every watershed for which we found data. Furthermore, brook trout populations declined almost universally, even in watersheds for which we recorded little to no industrial footprint. In Chapter 2, I examine historical and modern brook trout management initiatives, use an eco-evolutionary perspective to inform potential management & restoration strategies, and identify potential restoration watersheds using the historical GIS data from Chapter 1. I used these data to create a table of prioritized restoration sites by compiling watersheds that had both a high likelihood of historical migratory brook trout populations and also experienced little industrialization. With this information, we identified several locations in Wisconsin, Michigan, and northern Minnesota that may be optimal coaster restoration watersheds.
Book Synopsis Biochemical Genetic Evidence for Fish Stocks in Lake Trout (Salvelinus Namaycush), Bloater (Coregonus Hoyi), and Brook Trout (Salvelinus Fontinalis) in the Great Lakes Region by : Brian M. DuVall
Download or read book Biochemical Genetic Evidence for Fish Stocks in Lake Trout (Salvelinus Namaycush), Bloater (Coregonus Hoyi), and Brook Trout (Salvelinus Fontinalis) in the Great Lakes Region written by Brian M. DuVall and published by . This book was released on 1983 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effects of Climate Change on North-temperate Lake Trout (Salvelinus Namaycush) Populations by : Matthew Michael Guzzo
Download or read book The Effects of Climate Change on North-temperate Lake Trout (Salvelinus Namaycush) Populations written by Matthew Michael Guzzo and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aquatic ecosystems are expected to undergo major changes in response to climate change. Lake trout (Salvelinus namaycush) is predatory fish found in oligotrophic lakes of Canada and is considered a sentinel species for studying the impacts of warming on lakes due to its requirement for cold water. The objective of this thesis was to determine the impacts of warming on north-temperate lake trout populations. In Chapters 1-3, I used long-term datasets collected from small lakes near the southern extent of lake trout's distribution to determine how warming impacts thermal habitat and how these habitat changes cascade to alter the behaviour and growth of individuals and ultimately population-level characteristics of this species. I found that over a period when annual air temperatures increased by ≈ 2 ̊C there was a 14-day reduction, on average, in the ice-free season and an equal extension of summer - a period when littoral zone temperatures exceed the metabolic optimal for lake trout. Years with shorter springs and longer summers negatively impacts lake trout by limiting access to littoral prey, resulting in slower growth and reduced condition. I also found that the growth and size structure of an unexploited lake trout population shifted during this warming period; the population is now made up of a larger number of small individuals with lower condition and reduced life span. Lake trout also began to mature at younger ages and had reduced maximum size. Results suggest these changes in size-structure were not due to changes in the amount or size of prey fish or density-dependence, as the biomass of adult lake trout remained constant over time. In Chapter 4, I collected data from a northern lake to describe the seasonal ecology of this northern lake trout population and predict how warming might alter growth. I found that lake trout displayed similar seasonal cycles in habitat use and diet as in southern lakes, but that the use of littoral habitat was far reduced, likely due to the presence of pelagic prey fish and northern pike (Esox lucius) in this lake. Lastly, bioenergetic simulations indicated that the under a 2 ̊C warming scenario, the growth and consumption of lake trout would increase in this northern lake assuming prey was readily available.
Book Synopsis Working Papers Developed at the August 1983 Conference on Lake Trout Research by : Great Lakes Fishery Commission
Download or read book Working Papers Developed at the August 1983 Conference on Lake Trout Research written by Great Lakes Fishery Commission and published by . This book was released on 1985 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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