Download or read book Smoltification and Early Sexual Maturation in the Baltic Salmon Salmo Salar L written by Magnus Rydevik and published by . This book was released on 1989 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Precocious Sexual Maturation and Smolting in Baltic Salmon Salmo Salar L written by Hans Lundqvist and published by . This book was released on 1983 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sexual Maturation and Smoltification in Baltic Salmon Salmo Salar written by Ingemar Berglund and published by . This book was released on 1991 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Canadian Journal of Fisheries and Aquatic Sciences written by and published by . This book was released on 1999 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reproductive Seasonality in Teleosts written by Angus D. Munro and published by CRC Press. This book was released on 2019-11-11 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This important publication provides, for the first time, a comprehensive review of knowledge of reproductive seasonality in teleosts. It addresses why a particular species should show such seasonality, and how environmental cues act as regulators to ensure that reproductive maturation and breeding occur at the optimum time. The book considers the ultimate factors responsible for the evolution of reproductive seasonality in fish. It reviews salient concepts of reproductive seasonality in mammals. This volume also includes a review of accumulated knowledge of the control mechanisms of salmonids, gasterosteids, temperate cyprinids, cyprinodonts and other brackish-water forms, and marine and tropical freshwater teleosts. This is a work of value to research scientists in the field of environmental physiology, reproductive biology, and comparative neuroendocrinology and endocrinology. In addition, it is relevant for institutions involved with aquaculture and fisheries management. It is useful for post-graduate as well as undergraduate courses in fish biology and various related subjects.

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 The Effect of Extended Day Length on Early Sexual Maturation and Growth in Atlantic Salmon Salmo Salar Reared in Sea Cages written by and published by . This book was released on 1992 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two year-classes of Atlantic salmon, represented by a line selected for growth performance and a control line in one year-class and an unselected control line from a similar gene pool in a second year-class, were reared in sea cages. The fish were used to evaluate the effects of extended day length, using artificial light from fluorescent tubes, on growth and sexual maturity as grilse (maturation after one sea-year).

Download or read book Coastal Research in the Gulf of Bothnia written by K. Müller and published by Springer Science & Business Media. This book was released on 1982-04-30 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Canadian Journal of Zoology written by and published by . This book was released on 1993 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Management Strategies to Control Sexual Maturation in Sea reared Atlantic Salmon Salmo Salar L written by Eric Leclercq and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Pre-harvest sexual maturation in farmed Atlantic salmon, Salmo salar, remains a key biological bottleneck compromising biomass and financial output, production predictability, environmental respect, stock welfare and the overall sustainability of the on-growing industry. The management practices currently in place are not optimized and events of high maturation rate are still sporadically observed. From an ecological perspective, the escape of reproductively competent, domesticated Atlantic salmon constitutes a threat to the integrity of wild stocks. The forecasted expansion of the Scottish salmon industry compels the need for a comprehensive and more reliable control of sexual maturation. The general aim of this research project was to optimize the current management strategy (windows of light-manipulation and quality grading) and test alternative practices (lighting-technologies, selective harvest and triploidization) in the control of pre-harvest sexual maturation within the Atlantic salmon on-growing industry. In that end, a number of trials were performed using stock reared in sea-cages on a full commercial-scale or in tanks on an experimental scale. The results of this project are organized around three experimental chapters dealing consecutively with body-size dimorphism, grading and harvest quality; light manipulations and triploidy. In each chapter, two original manuscripts either published or in review are included. In addition to these experimental results, a literature review chapter composed of two review papers on the photoperiodic synchronization and developmental regulation of maturation in salmonids and on morphological skin colour changes in teleosts (published) are presented. In the first experimental chapters, we aimed at investigating the possibility of detecting and selectively harvesting a high proportion of sexually recruited fish before flesh quality deterioration. Results clearly showed that body-size dimorphisms between maturity cohorts at the end of the anabolic window of reproduction (June/July) are strong and standard predictors of maturation among related populations with the same freshwater history. Dimorphism can therefore be modelled to easily and accurately estimate maturation rate in a number of discrete rearing-units. If required, a high proportion of sexually recruited fish can be selectively harvested as superior quality product while leaving the immature fish for further on-growing. This provides an alternative to visual grilse grading that is not feasible in large-scale aquaculture systems, prevents downgrading and increases production predictability as compared to emergency harvests. Furthermore, our results showed immature males grow faster than immature females which should be further investigated to fully determine gender specific performances and nutritional requirements. Weight-grading performed earlier in the cycle affects the sex-ratio within individual pens and in turn apparent performance. This work also revealed that Atlantic salmon can exhibit significant variations in skin colouration resembling the onset of nuptial display but that are not related to sexual recruitment and do not correlate with reduced flesh quality. This originates from a lack of purine (silver) pigments which was also identified, to a larger extent, as characteristic of the nuptial display. This suggests a degree of desmoltification in these histologically immature fish. The instrumental colouration of the altered phenotype was shown to be improved towards a more silver-like appearance by direct ice-contact. This knowledge could facilitate post-harvest quality grading towards the most appropriate market channel and increase product acceptance and attractiveness. The second experimental chapter investigated the possibility of improving photoperiodic manipulation used to suppress early maturation, currently applied for 6-months during the second winter at sea using wide-spectrum, high-intensity lighting systems. Our results showed that the window of continuous artificial-light (LL) exposure can be reduced to 4-months following its onset in early January without compromising its efficiency in suppressing pre-harvest maturation. In addition, alternative lighting technologies were also highly potent at suppressing sexual maturation. The mean-irradiance (intensity) generated within a commercial sea-cage was inversely proportional to the suppression of nocturnal plasma melatonin (light perception hormone) and negatively correlates with the maturation rate within the commercial sea-pen. Threshold levels of light-intensity required to achieve optimal (total) suppression of sexual maturation are suggested. Alternative, narrow band-width lighting-technologies (cold cathode and light-emitting diodes) present an array of technical, practical, economic and welfare benefits comparing to the system currently in use. Clear improvements of the photoperiod-manipulation strategy were demonstrated and these would reduce economic and environmental costs but also potential impacts on animal welfare. The third experimental chapter showed the strong potential of sterile-triploid Atlantic salmon stocks both in freshwater and seawater. Triploid out-of-season smolts were produced for the first time using a classical accelerated "square-wave" photoperiod. Triploidization affected the smoltification pattern but had no detrimental effects on freshwater and early seawater performances under both a S0+ and S1 regime. This illustrates the need to adapt the timing of seawater transfer for successfully producing triploid Atlantic salmon post-smolts. Following one year of seawater rearing, the prevalence of external deformities was higher in triploids but remained within acceptable levels. Importantly, the incidence of vertebral deformities and ocular cataract was higher in triploids possibly due to their specific requirements. It is suggested that tailoring the diet to the nutritional requirements of triploids holds strong potential for remediation. This must be addressed if the use of sterile-triploid stock is to become a commercial reality. The present research project provides means to optimize the maturation management strategy within the Atlantic salmon on-growing industry through light-manipulation, maturation detection and selective harvest, and quality grading. Proposed improvements have the potential to increase biomass and financial output, production predictability, environmental respect and animal welfare and will allow standardization of the overall control of pre-harvest sexual maturation. Their implementation provides a comprehensive strategy likely to favour a sustainable expansion of the Atlantic salmon industry. From a longer term perspective, the rearing of sterile-triploid stocks is promising and should be actively investigated to isolate domesticated strains from their wild conspecifics. This would also eliminate the need for on-growers to deploy a maturation management strategy that that might still affect stock welfare and remains, despite the strong improvements demonstrated, not 100% reliable, costly, technical and protracted.

Download or read book Sexual Maturation in Atlantic Salmon Salmo Salar L Aspects of Environmental and Hormonal Control written by Geir Lasse Taranger and published by . This book was released on 1993 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evolutionary Biology of the Atlantic Salmon written by Tomislav Vladić and published by CRC Press. This book was released on 2015-08-10 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atlantic salmon (Salmo salar, L) is an anadromous species contributing to major fishery catches and comprising a significant part of the aquaculturally produced fish for human consumption. The aim of this book is to incite the interest in the field of knowledge gathered from a broad scope of disciplines that have investigated this fish species. Und

Download or read book Sexual Maturation in Farmed Atlantic Salmon Salmo Salar written by Margarita Rivera and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sexual maturation of Atlantic salmon Salmo salar is a multifactorial process in which fish acquire somatic characteristics to reproduce. In salmon farming has been described a high variability in the trait age at maturation derived from wild reproductive strategies. Early maturation is a phenotype that generates serious economic repercussions on both, sea cage and on land-based aquaculture systems. In view of the challenges of this problem for the global salmon farming industry, it is essential to thoroughly understand the influencing factors of early and late maturation to find efficient alternatives for managing the phenomenon. This review briefly describes sexual maturation in S. salar, its variability in cultures, and the factors influencing the maturation age trait at the physiological, genetic and environmental levels. The control of early maturity through changes to the natural photoperiod and through the use of genetic markers are discussed.

Download or read book Parr smolt Transformation in Nonanadromous Atlantic Salmon Salmo Salar and Effects of Sexual Maturation on the Parr smolt Transformation in Male Anadromous Atlantic Salmon written by Timothy Peter Birt and published by . This book was released on 1985 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Brown Trout written by Javier Lobón-Cerviá and published by John Wiley & Sons. This book was released on 2017-10-13 with total page 881 pages. Available in PDF, EPUB and Kindle. Book excerpt: Brown Trout: Biology, Ecology and Management A comprehensive guide to the most current research, history, genetics and ecology of the brown trout including challenging environmental problems The brown trout is an iconic species across its natural European distribution and has been introduced throughout the World. Brown Trout offers a comprehensive review of the scientific information and current research on this major fish species. While the brown trout is the most sought species by anglers, its introduction to various waters around the world is causing serious environmental problems. At the same time, introduction of exogenous brown trout lineages threats conservation of native gene pools of populations in many regions. The authors summarize the important aspects of the brown trout’s life history and ecology and focus on the impact caused by the species. The text explores potential management strategies in order to maintain numerous damaged populations within its natural distributional range and to ameliorate its impacts in exotic environments. The authors include information on a wide-range of topics such as recent updates in population genetics, evolutionary history, reproductive traits and early ontogeny, life history plasticity in anadromous brown trout and life history of the adfluvial brown trout and much more. This vital resource: Contains the latest research on the biology and ecology of brown trout Includes information on phylogeography, genetics, population dynamics and stock management Spotlights the brown trout’s introduction to regions around the world and the serious environmental impacts Offers a comprehensive review of conservation and management techniques Written for salmonid scientists and researchers, fishery and environmental managers, and students of population genetics, ecology and population dynamics, Brown Trout explores the most recent findings on the history, ecology and sustainability of this much-researched species.

Download or read book Proceedings of the Fifth International Symposium on the Reproductive Physiology of Fish written by Frederick William Goetz and published by . This book was released on 1995 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this meeting is to serve as a forum for the communication of recent advances on all aspects of reproductive physiology of fish. The meeting had eight oral sessions covering the pituitary and gonadotropins, the hypothalamus and brain, aquaculture, environmental influences on reproduction, reproductive life histories, reproductive behavior, gonadal physiology and gametogenesis.

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