Download or read book State of Sexual Maturity of Atlantic Salmon Salmo Salar L Caught at Sea in Commercial Fisheries Off Newfoundland written by Conrad Mullins and published by . This book was released on 1995 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book State of Sexual Maturity of Atlantic Salmon Salmo Salar L Caught at Sea in Commercial Fisheries Off Newfoundland written by Conrad Mullins and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Length Weight Sex and Age Characteristics of Atlantic Salmon Salmo Salar of North American and European Origin Caught at West Greenland in 1979 written by David G. Reddin and published by . This book was released on 1981 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Atlantic salmon (Salmo salar L.) from research vessel catches and samples of commercial catches at West Greenland in 1979 were analyzed for fork length, weight and smolt age differences among fish identified to continent of origin (either North American wild or hatchery, or European origin). There were no significant differences in the fork lengths, weights and smolt ages of male and female salmon, of salmon caught in NAFO Div. 1AB and 1CD, and of salmon caught by research vessel and by commercial fishery. However, North American wild origin salmon were shorter, weighed less, and had a higher mean smolt age than did salmon of European origin."--Abstract.
Download or read book Seasonal Trends in the Biological Characteristics of Atlantic Salmon Salmo Salar L Catches in the 1974 76 Commercial Fishery at Portugal Cove Newfoundland written by Canada. Dept. of Fisheries and Oceans. Newfoundland Region. Fisheries Research Branch and published by St. John's, Nfld. : Fisheries and Oceans, Canada. This book was released on 1984 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seasonal Trends in the Biological Characteristics of Atlantic Salmon salmo Salar L Catches in the 1974 76 Commercial Fishery at Portugal Cove Newfoundland written by Canada. Department of Fisheries and Oceans and published by . This book was released on 1984 with total page 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 Seasonal Trends in the Biological Characteristics of Atlantic Salmon Salmo Salar L Catches in the 1974 76 Commercial Fisheries at Portugal Cove Newfoundland written by D.g Reddin and published by . This book was released on 1984 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Studies on the Biology of Sexually Mature Male Salmon Parr Salmo Salar Linnaeus 1758 in Insular Newfoundland written by Edgar L. Dalley and published by 1978.. This book was released on 1978 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Temporal and Spatial Variability in Density Relative Condition Gender Composition and Maturity Status of Atlantic Salmon Salmo Salar L Parr in the Harry s River Drainage System Insular Newfoundland written by Jennifer Fitzgerald and published by . This book was released on 1999 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary of the Atlantic Salmon Salmo Salar L Fishery in Northern Labrador written by Canada. Fisheries and Marine Service and published by . This book was released on 1979 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Status of Atlantic Salmon Salmo Salar L in Selected Rivers with Counting Facilities in the Newfoundland Region written by Canada. Department of Fisheries and Oceans. Science and published by St. John's, Nfld. : Canadian Atlantic Fisheries Scientific Advisory Committee. This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atlantic Salmon Salmo Salar L Egg to smolt Survival in Newfoundland Rivers written by M. F. O'Connell and published by [Dartmouth, N.S.] : Canadian Atlantic Fisheries Scientific Advisory Committee. This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary of Marine Tagging Studies of Atlantic Salmon Salmo Salar L in the Northwest Atlantic Area written by Canada. Dept. of Fisheries and Oceans. Newfoundland Region. Science Branch and published by St. John's, Nfld. : Fisheries and Oceans, Canada. This book was released on 1990 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Photoperiod on Growth and Maturation of Atlantic Salmon Salmo Salar in the Bay of Fundy written by P. R. Harmon and published by St. Andrews, N.B. : Department of Fisheries and Oceans. This book was released on 2003 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2001, a study on the effects of photoperiod on growth and early maturation was initiated on a commercial salmon farm in southwestern New Brunswick. Three cages (70-m diameter circles) had lights turned on November 21. A second set of three cages had lights turned on February 15, 2002. Lights were left on 24 h per day. All lights were turned off on May 31, 2002. Six unlit cages served as controls.
Download or read book Oceanic Abstracts written by and published by . This book was released on 1996-10 with total page 1002 pages. Available in PDF, EPUB and Kindle. Book excerpt:
