Management strategies to control sexual maturation in sea-reared Atlantic salmon (Salmo salar L.): Biomass management, light-manipulation and sterility

• Main Author: Leclercq, Eric
• Other Authors: Migaud, Hervé, Taylor, John F., Bell, J. Gordon, Biotechnology and Biological Sciences Research Council (BBSRC) Marine Harvest (Scotland) Ltd., School of Natural Sciences, Aquaculture
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Stirling 2010
• Subjects: Atlantic salmon; Sexual maturation; Dimorphism; flesh quality; Pigmentation; Light-manipulation; light-technology; Triploidization; smoltification; Fishes Quality; Salmon fisheries Scotland Management; Salmo salar
• Online Access: http://hdl.handle.net/1893/2656; http://dspace.stir.ac.uk/bitstream/1893/2656/1/EricLeclercqPhDThesis.pdf

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 ...