Download or read book Linking Density dependent Survival and Growth of Juvenile Atlantic Salmon to Their Predators and Prey written by Darren M. Ward and published by . This book was released on 2007 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Juvenile, stream-dwelling salmon are a model system for studies of density dependence. However, while salmon exhibit diverse mechanisms and patterns of density dependence, the factors that drive variation in density dependence are not clear. I used the unique experimental setting of an ongoing population restoration effort to identify key factors that limit survival and growth of juvenile Atlantic salmon (Salmo salar), then tested how these factors interact with density dependence. Using a large-scale salmon population density manipulation in natural streams, I showed that slimy sculpin (Cottus cognatus), a common predator of salmon, limited salmon survival and reversed the direction of density dependence. Sculpin dramatically suppressed salmon survival at low salmon population density, but had little effect on survival at high salmon density. Such predator-mediated inverse density dependence can eliminate low-density populations even if predators have little effect when prey are abundant. Individual growth of juvenile salmon was also density dependent. Fish stocked at low density grew faster than those stocked at high density, and mean growth increased even more when high mortality further reduced population density. Increased growth may help compensate for decreased population abundance. However, variation in prey availability across streams, not population density, explained most of the variation in individual growth. Thus, the demographic effects of density-dependent growth depend on stream productivity. I also used the salmon restoration program as a controlled setting to investigate another applied problem: accumulation of toxic mercury in fish. Conducting ecological research within the applied context of an intensively managed population provides unique opportunities for direct application of the results as well as insight into the fundamental factors that drive population dynamics.

Download or read book Dispersal and Density dependent Growth of Early Juvenile Atlantic Salmon Salmo Salar written by Eric Brunsdon and published by . This book was released on 2015 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dispersal from nesting sites and habitat selection are essential for the fitness of young individuals and shapes the distribution, growth and persistence of populations. These processes are important to consider when releasing captive bred young individuals into the wild to restore extirpated or depleted populations. However, few studies have evaluated how manipulating densities during release affects the dispersal and growth of individuals with respect to crucial life history traits. I manipulated the density of young-of-the-year (YOY) Atlantic salmon to evaluate the effect of two stocking techniques on the life history characteristics of surviving fish. Salmon were either point-stocked (all fish released in a small area at the upstream end of a reach) or spread-stocked (fish were released evenly over the entire reach) in 14 reaches of the Boquet River, New York. I used snorkeling and electrofishing surveys to characterize the density, dispersal, growth and survival of salmon stocked via each technique. Density decreased and growth rate increased with distance downstream in point-stocking reaches, whereas density and growth were relatively constant within spread-stocking reaches. Overall, density, growth and survival did not differ between the two stocking techniques due to the greater-than-expected degree of dispersal observed in point-stocking reaches. YOY dispersed up to 1600m, with 41% moving over 200m downstream. Growth rate of individual fish was density-dependent, following the negative power curve observed in previous studies. My results provide insights into how the growth and survival of released individuals are altered via stocking techniques, ultimately shaping their distribution and persistence.

Download or read book Age Growth and Mortality of Juvenile Atlantic Salmon in Streams written by Patrick W. Bley and published by . This book was released on 1987 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atlantic Salmon Ecology written by Øystein Aas and published by John Wiley & Sons. This book was released on 2011-07-05 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Atlantic salmon is one of the most prized and exploited species worldwide, being at the centre of a massive sports fishing industry and increasingly as the major farmed species in many countries worldwide. Atlantic Salmon Ecology is a landmark publication, both scientifically important and visually attractive. Comprehensively covering all major aspects of the relationship of the Atlantic salmon with its environment, chapters include details of migration and dispersal, reproduction, habitat requirements, feeding, growth rates, competition, predation, parasitsm, population dynamics, effects of landscape use, hydro power development, climate change, and exploitation. The book closes with a summary and look at possible future research directions. Backed by the Norwegian Research Council and with editors and contributors widely known and respected, Atlantic Salmon Ecology is an essential purchase for all those working with this species, including fisheries scientists and managers, fish biologists, ecologists, physiologists, environmental biologists and aquatic scientists, fish and wildlife department personnel and regulatory bodies. Libraries in all universities and research establishments where these subjects are studied and taught should have copies of this important publication. Comprehensive and up-to-date coverage of Atlantic Salmon Atlantic Salmon is one of the world's most commercially important species Backed by the Norwegian Research Council Experienced editor and internationally respected contributors

Download or read book Ecology of Atlantic Salmon and Brown Trout written by Bror Jonsson and published by Springer Science & Business Media. This book was released on 2011-05-03 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Destruction of habitat is the major cause for loss of biodiversity including variation in life history and habitat ecology. Each species and population adapts to its environment, adaptations visible in morphology, ecology, behaviour, physiology and genetics. Here, the authors present the population ecology of Atlantic salmon and brown trout and how it is influenced by the environment in terms of growth, migration, spawning and recruitment. Salmonids appeared as freshwater fish some 50 million years ago. Atlantic salmon and brown trout evolved in the Atlantic basin, Atlantic salmon in North America and Europe, brown trout in Europe, Northern Africa and Western Asia. The species live in small streams as well as large rivers, lakes, estuaries, coastal seas and oceans, with brown trout better adapted to small streams and less well adapted to feeding in the ocean than Atlantic salmon. Smolt and adult sizes and longevity are constrained by habitat conditions of populations spawning in small streams. Feeding, wintering and spawning opportunities influence migratory versus resident lifestyles, while the growth rate influences egg size and number, age at maturity, reproductive success and longevity. Further, early experiences influence later performance. For instance, juvenile behaviour influences adult homing, competition for spawning habitat, partner finding and predator avoidance. The abundance of wild Atlantic salmon populations has declined in recent years; climate change and escaped farmed salmon are major threats. The climate influences through changes in temperature and flow, while escaped farmed salmon do so through ecological competition, interbreeding and the spreading of contagious diseases. The authors pinpoint essential problems and offer suggestions as to how they can be reduced. In this context, population enhancement, habitat restoration and management are also discussed. The text closes with a presentation of what the authors view as major scientific challenges in ecological research on these species.

Download or read book Production of Juvenile Atlantic Salmon Salmo Salar in Natural Waters written by National Research Council Canada and published by NRC Research Press. This book was released on 1993 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Up-to-date information, knowledge and research in progress in scientific fields related to natural production of juvenile Atlantic salmon and some other ecologically similar fluvial salmonids is contained in the 25 papers and 12 abstracts contained in this publication, which were prepared for an international symposium held in St. John's, Newfoundland. Studies relate to stream ecology, invertebrates and predators, habitat improvement, competitive effects, behaviour and dispersal, habitat and production of juvenile salmon, population dynamics and relationships of juvenile salmon estimates to smolt yields. A list of participants at the conference is also provided.

Download or read book The Atlantic Salmon written by Eric Verspoor and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atlantic Salmon is a cultural icon throughout its North Atlantic range; it is the focus of probably the World’s highest profile recreational fishery and is the basis for one of the World’s largest aquaculture industries. Despite this, many wild stocks of salmon are in decline and underpinning this is a dearth of information on the nature and extent of population structuring and adaptive population differentiation, and its implications for species conservation. This important new book will go a long way to rectify this situation by providing a thorough review of the genetics of Atlantic salmon. Sponsored by the European Union and the Atlantic Salmon Trust, this book comprises the work of an international team of scientists, carefully integrated and edited to provide a landmark book of vital interest to all those working with Atlantic salmon.

Download or read book Further Evaluation of Juvenile Atlantic Salmon Salmo Salar L Abundance in the Experimental Ponds Area Relative to Subsequent Adult Returns to the Gander River and the Empirical Evidence for Density dependent Marine Mortality written by R. Knoechel and published by . This book was released on 2000 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Territoriality and Population Regulation in Juvenile Salmonids written by István Imre and published by . This book was released on 2003 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Dynamics of Exploited Fish Populations written by Raymond J.H. Beverton and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among the fishes, a remarkably wide range of biological adaptations to diverse habitats has evolved. As well as living in the conventional habitats of lakes, ponds, rivers, rock pools and the open sea, fish have solved the problems of life in deserts, in the deep sea, in the cold antarctic, and in warm waters of high alkalinity or of low oxygen. Along with these adaptations, we find the most impressive specializations of morphology, physiology and behaviour. For example we can marvel at the high-speed swimming of the marlins, sailfish and warm-blooded tunas, air-breathing in catfish and lungfish, parental care in the mouth-brooding cichlids, and viviparity in many sharks and toothcarps. Moreover, fish are of considerable importance to the survival of the human species in the form of nutritious, delicious and diverse food. Rational exploitation and management of our global stocks of fishes must rely upon a detailed and precise insight of their biology. The Chapman & Hall Fish and Fisheries Series aims to present timely volumes reviewing important aspects of fish biology. Most volumes will be of interest to research workers in biology, zoology, ecology and physiology but an additional aim is for the books to be accessible to a wide spectrum of non-specialist readers ranging from undergraduates and postgraduates to those with an interest in industrial and commercial aspects of fish and fisheries.

Download or read book The Influence of Structural Complexity on Phenotypic Development and Post release Performance of Juvenile Atlantic Salmon Salmo Salar written by John James Winkowski and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The environment can play an integral role on phenotypic development of an organism. In this thesis, I experimentally tested the influence of structural complexity on phenotypic development and post-release performance of juvenile Atlantic salmon (Salmo salar) when released into semi-natural and natural environments. From an applied perspective, I was interested in investigating alternative rearing strategies of juvenile Salmo salar with the goal of enhancing performance of fish when released into nature. In my first data chapter, I conducted an experiment to test the influence of environmental enrichment during incubation (i.e. addition of gravel to create a "complex" environment) on the phenotype and performance of juvenile salmon in a semi-natural environment. At the culmination of endogenous feeding (i.e. "emergence"), fish that incubated in a complex environment were heavier, in better body condition, fed more on novel prey, and took longer to reappear from a shelter after a simulated predator attack. In addition, when transferred from incubation environments to semi-natural stream channels, fish originating from the complex incubation environment expressed enhanced growth and survival. These findings suggest that Salmo salar are plastic to environmental factors during incubation and developmental differences could be contributing to performance in semi-natural stream channels. There were, however, no commensurate differences in brain volume with those observed in behaviour and performance, which may suggest that other developmental processes in the brain of juvenile Atlantic salmon are occurring that are not reflected in overall brain volume. In my second data chapter, I reared the fish from the preceding incubation study for 60 days after emergence in tanks with ("complex") or without cobble substrate ("simple"). I used a reciprocal approach to rearing and moved fish between complex and simple environments for two 30-day rearing periods to investigate if timing or duration of timing of exposure to habitat complexity influenced growth and condition in the hatchery and subsequent survival in semi-natural and wild environments. I found that fish reared in complex tanks exhibited higher body condition (i.e. heavier for a given length) for the first 30 days, however, differences generally faded during the second 30 days of hatchery rearing. Additionally, I observed rearing groups with smaller fish, on average, at release expressed higher growth rates in semi-natural stream channels and in the wild, such that sizes and conditions did not differ among groups at final recapture. Estimated survival after release into the wild (over ca. 260 days) was higher for fish incubated in a complex environment and reared in a simple environment for consecutive 30 d rearing periods (Complex>Simple>Simple, or "CSS") and those in SCC treatment than fish from 3 of the 7 other groups (CCC, CSC, SSC). There were no other differences in survival between treatment groups. Survival in the semi-natural stream channels was high (> 85%) and I did not detect differences between groups. The results presented in this thesis suggest that phenotypic traits of juvenile Atlantic salmon are sensitive to environmental factors early in development. Enriched environments containing gravel and cobble may serve to provide cover for juvenile fish during early life, allowing them to rest, hide from predators, metabolize, and allocate energy towards somatic growth and development. Such enrichment can provide fish an advantage when released into the wild, though effects may be complicated. As a rearing strategy for the release of salmon into nature to re-establish depleted populations, modifications are likely needed to simplify maintenance of rearing tanks, however this study serves as a benchmark for future efforts at alternative rearing techniques for enhancing performance of released juvenile Salmo salar in nature.

Download or read book Atlantic Salmon in Maine written by National Research Council and published by National Academies Press. This book was released on 2004-09-07 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of the pervasive and substantial decline of Atlantic salmon populations in Maine over the past 150 years, and because they are close to extinction, a comprehensive statewide action should be taken now to ensure their survival. The populations of Atlantic salmon have declined drastically, from an estimated half million adult salmon returning to U.S. rivers each year in the early 1800s to perhaps as few as 1,000 in 2001. The report recommends implementing a formalized decision-making approach to establish priorities, evaluate options and coordinate plans for conserving and restoring the salmon.

Download or read book Linking Freshwater Growth to Size dependent Marine Survival of Sockeye Salmon written by Marta Elizabeth Ree and published by . This book was released on 2019 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the mediating role of body size in determining fitness, the ‘bigger is better’ hypothesis still pervades evolutionary ecology despite evidence that natural selection on phenotypic traits varies in time and space. For Pacific salmon (genus Oncorhynchus), the size at which juveniles migrate to sea (i.e., smolts) has been linked to survival during the early marine period, where larger smolts typically survive at a higher rate than their smaller counterparts. However, the relationship of smolt size and survival becomes more ambiguous when considering confounding factors of age, ocean entry timing, and environmental variability. Despite equivocal results, smolt size appears to be a key trait and therefore changes in freshwater conditions may have consequences for population productivity. Furthermore, due to differences in site-specific habitats, trophic dynamics, and population traits the response of specific populations to these changes is likely to be context specific. The objective of this thesis was to 1) quantify the direction and magnitude of natural selection on smolt size for three age classes of sockeye salmon in a small watershed on Kodiak Island, AK and 2) explore stock-specific effects of temperature and conspecific density on smolt size over a multi-decade time-series to understand historic and possible future trends. To address our first objective, we calculated standardized selection differentials by comparing observed size distributions of out-migrating juvenile salmon to back-calculated smolt length from the scales of surviving, returning adults. Results reveal the magnitude of selection on size was very strong and consistent among years. However, the direction of selection on size consistently varied among age classes. The absolute magnitude of selection was negatively correlated to apparent marine survival and positively correlated to late mean ocean entry timing. To address our second objective, we back-calculated smolt size from returning adult scales to reconstruct a time-series of smolt length of two stocks within a small Alaska watershed on Kodiak Island. Using a dynamic linear model framework, we detected evidence that for one stock, temperature was important in explaining smolt length, and density effects influenced both stocks utilizing the same lakes. Furthermore, forecasts of smolt length showed highly variable responses under scenarios of increasing temperature and high and low densities. Collectively, these results demonstrate that interactions between processes of climate, density, and natural selection are highly context-specific in terms of both inter- and intra- population variability.

Download or read book Juvenile Atlantic Salmon Salmo Salar L Abundance in the Experimental Ponds Area Relative to Subsequent Adult Returns to the Gander River as an Index of Marine Survival Apparent Evidence for Density dependent Marine Mortality written by R. Knoechel and published by . This book was released on 1999 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Juvenile Atlantic Salmon Salmo Salar L Abundance in the Experimental Ponds Area Relative to Subsequent Adult Returns to the Gander River as an Index of Marine Survival Apparent Evidence for Density dependent Marine Mortality written by R. Knoechel and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Variability in the Energy Density of Prey and Its Consequences for Growth in Juvenile Chinook Salmon written by Jacob Daniel Cole Weil and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding how energy flows through ecosystems reveals underlying ecological patterns that can drive processes such as growth and survival of organisms. To understand how energy is transferred through organisms, the energy content or energy density (ED) of both consumers and prey must be determined. To facilitate the ease of ED measurement across taxa, I developed a model to estimate the ED of organisms using percent ash-free dry weight (AFDW). Using data obtained from 11 studies with broad taxonomic, temporal and spatial coverage, I compared common predictors of ED using linear models. AFDW was determined to be the superior predictor of ED relative to previous metrics and was predictive for a broad range of taxonomic groups including aquatic invertebrates, aquatic vertebrates, aquatic plants and terrestrial invertebrates. This AFDW model enables measurement of ED with minimal cost and time investment, which allows ED to be more readily determined for diverse taxa. Next, I applied the AFDW method to the diet of a pelagic consumer, juvenile Chinook Salmon, to determine the effect of variable prey ED on growth. In 2017, I collected monthly zooplankton and fish samples of known importance in the diet of juvenile Chinook Salmon to look for fine-scale taxonomic, temporal and spatial differences in ED. Decapod zoeae and megalopae differed significantly from each other and showed family level variability in ED. Amphipods also showed significant species-level variability in ED. Temporal differences were observed, but did not reveal a consistent pattern among groups. Spatial variability was not significant. Using bioenergetics models, growth of juvenile Chinook Salmon was predicted to be greater when using fine-scale ED estimates. This difference was not substantial on average, but in some cases represented more than a two-fold difference in growth between coarse- and fine-scale estimates. These results suggest the need for higher resolution diet ED data when determining growth projections for juvenile Chinook Salmon. With the aid of the AFDW model presented in this thesis, the effort required to obtain these data is greatly reduced.

Download or read book Stock Recruitment and Reference Points written by Etienne Prévost and published by Quae. This book was released on 2001-01-01 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book collects the available knowledge about the ecology of Atlantic salmon and contemporary stock assessment methods supporting the specific task of establishing reference points. Bayesian approaches for incorporating uncertainty are front and centre in the book. Stock and recruitment analysis methods, transport of reference points, risk analysis and use of index measures of abundance are presented in a format which can be readily understood and applied by scientists, educators, professionals and undergraduate students.