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 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 Endocrine Regulation of Early Sexual Maturation in Male Atlantic Salmon Parr written by Gersende Maugars and published by . This book was released on 2007 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Atlantic Salmon Ecology written by Øystein Aas and published by John Wiley & Sons. This book was released on 2010-10-18 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 Reproductive Biotechnology in Finfish Aquaculture written by C.-S. Lee and published by Elsevier. This book was released on 2012-12-02 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The successful reproduction of cultured brood stock is essential to the sustainable aquaculture of aquatic organisms. This book describes recent advances in the field of finfish reproductive biotechnology. The chapters in this volume are written by eminent scientists who review the progress and assess the status of biotechnology research that is applicable to the reproduction of finfish species for aquaculture. A wide range of topics is included starting with broodstock technologies such as broodstock genetics, broodstock nutrition, environmental control of maturation and impacts of stress on broodstock, gametes and progeny. The volume includes technologies for induction of ovulation and spermiation using synthetic hypothalamic peptides. Gamete technologies which are described include cryopreservation, chromosome set manipulation, disease prevention and control for gametes and embryos and the development of transgenic fish with enhanced production characteristics. Genetic and endocrine technologies for the production of monosex male and female fish stocks are also described.The closing chapter summarizes the discussion of each topic at the workshop, provides recommendations to industry and describes priorities of research and development. Researchers as well as teaching faculty in the aquaculture field will find this volume of great value.

Download or read book Environmental Regulation of Smolting and Maturation in Atlantic Salmon Salmo Salar L Parr written by Colin Ean Adams and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Endocrine Aspects of Sexual Maturity in Male Atlantic Salmon Parr Salmo Salar L Juv written by P. A. C. Stuart-Kregor and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sex Control in Aquaculture written by Hanping Wang and published by John Wiley & Sons. This book was released on 2018-11-08 with total page 1810 pages. Available in PDF, EPUB and Kindle. Book excerpt: Awarded Bookauthority's "Best Aquaculture Books of all Time" A comprehensive resource that covers all the aspects of sex control in aquaculture written by internationally-acclaimed scientists Comprehensive in scope, Sex Control in Aquaculture first explains the concepts and rationale for sex control in aquaculture, which serves different purposes. The most important are: to produce monosex stocks to rear only the fastest-growing sex in some species, to prevent precocious or uncontrolled reproduction in other species and to aid in broodstock management. The application of sex ratio manipulation for population control and invasive species management is also included. Next, this book provides detailed and updated information on the underlying genetic, epigenetic, endocrine and environmental mechanisms responsible for the establishment of the sexes, and explains chromosome set manipulation techniques, hybridization and the latest gene knockout approaches. Furthermore, the book offers detailed protocols and key summarizing information on how sex control is practiced worldwide in 35 major aquaculture species or groups, including fish and crustaceans, and puts the focus on its application in the aquaculture industry. With contributions from an international panel of leading scientists, Sex Control in Aquaculture will appeal to a large audience: aquaculture/fisheries professionals and students, scientists or biologists working with basic aspects of fish/shrimp biology, growth and reproductive endocrinology, genetics, molecular biology, evolutionary biology, and R&D managers and administrators. This text explores sex control technologies and monosex production of commercially-farmed fish and crustacean species that are highly in demand for aquaculture, to improve feed utilization efficiency, reduce energy consumption for reproduction and eliminate a series of problems caused by mixed sex rearing. Thus, this book: Contains contributions from an international panel of leading scientists and professionals in the field Provides comprehensive coverage of both established and new technologies to control sex ratios that are becoming more necessary to increase productivity in aquaculture Includes detailed coverage of the most effective sex control techniques used in the world's most important commercially-farmed species Sex Control in Aquaculture is the comprehensive resource for understanding the biological rationale, scientific principles and real-world practices in this exciting and expanding field.

Download or read book The Israeli Journal of Aquaculture written by and published by . This book was released on 1988 with total page 336 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 Growth Respiration and Sexual Maturation of Juvenile Atlantic Salmon Salmo Salar L written by Robert Louis Blake and published by . This book was released on 1981 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Endocrine Aspects of Sexual Maturity in Male Atlantic Salmon Parr written by Paul Anthony Charles Stuart-Kregor and published by . This book was released on 1981 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth Hormone and Somatolactin Function During Sexual Maturation of Female Atlantic Salmon written by Susana Benedet Perea and published by . This book was released on 2008 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: