Establishing the optimal salinity for rearing salmon in recirculating aquaculture systems by Joshua David Emerman B.S., University of New England, 2010 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Zoology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) February, 2016 © Joshua David Emerman, 2016 Abstract Aquaculture of salmon worldwide is a 15.3 billion dollar industry and the majority of fish are produced in net-pen systems in coastal waters. Recently producers have begun investigating the feasibility of moving salmon production onto land and into recirculating aquaculture systems (RAS). The major downsides to RAS are the startup and operational costs; however the ability to optimize many environmental variables to enhance growth and feed conversion, something impossible to do in net-pen systems, may help defray these otherwise prohibitive costs. Salinity may be the most important of these variables due to the metabolic cost of osmoregulation, which has been estimated to account for 5-50% of routine metabolic rate. Decreased osmoregulatory costs could result in a greater allocation of energy toward growth, thus shortening production times and improving feed conversion efficiency. To establish an optimal salinity for growth in salmon, seven replicate, 15,000 liter RAS were constructed at the University of British Columbia’s InSEAS research facility. I conducted a preliminary study to validate that each system was able to control water quality parameters and yield similar levels of growth and feed conversion in coho salmon (Oncorhynchus kisutch). I then conducted salinity trials with Atlantic (Salmo salar) and coho salmon. Fish were grown in five salinities ranging from freshwater to seawater (0, 5, 10, 20, 30 ppt) for approximately five months. Growth rates and feed conversion ratios (FCR) were measured throughout the trial. The fastest growth rate and lowest FCR in coho salmon was at 10 ppt, which is approximately isosmotic to the blood. Growth rate of coho at intermediate salinities was almost double that at 0 or 30 ppt through the first growth period. This trend was not seen during the second coho growth period, possibly due to a size-dependent or density effect. Unexpectedly, salinity had no effect on growth rate and FCR in Atlantic salmon, although growth rates were consistent with those seen in industry. This research will help further ii move salmon production out of the oceans and onto land, alleviating some of the environmental costs associated with salmon grown in the oceans. iii Preface I conducted all of the research under the supervision of Drs. Jeffrey G. Richards and Colin J. Brauner. I wrote all 4 chapters of the thesis and received editorial feedback from Drs. Colin J. Brauner, Jeffrey G. Richards, and Anthony P. Farrell. Treatment and experimental protocols involving animals were followed according to The University of British Columbia’s Animal Care Committee, certificate A13-0016. iv Table of Contents Abstract .......................................................................................................................................... ii Preface ........................................................................................................................................... iv Table of Contents ...........................................................................................................................v List of Tables .............................................................................................................................. viii List of Figures ............................................................................................................................... ix List of Abbreviations ................................................................................................................... xi Acknowledgements ..................................................................................................................... xii Chapter 1: General Introduction .................................................................................................1 1.1 History of Aquaculture ......................................................................................................... 1 1.2 Aquaculture of Salmon and Environmental Impacts ............................................................ 4 1.3 Recirculating Aquaculture .................................................................................................... 7 1.4 Salinity .................................................................................................................................. 9 1.5 Research Goals.................................................................................................................... 12 Chapter 2: Validation of a novel RAS research facility: InSEAS ...........................................14 2.1 Summary ............................................................................................................................. 14 2.2 Introduction ......................................................................................................................... 15 2.3 Methods............................................................................................................................... 20 2.3.1 Overview ...................................................................................................................... 20 2.3.2 Experimental Design .................................................................................................... 20 2.3.3 Water Parameter Testing & Analysis .......................................................................... 22 2.3.4 Calculations.................................................................................................................. 23 2.3.4.1 Growth Rates ........................................................................................................ 23 2.3.5 Statistical Analysis ....................................................................................................... 24 2.4 Results ................................................................................................................................. 24 2.4.1 Water Parameters ......................................................................................................... 24 2.4.2 Freshwater Growth Trial .............................................................................................. 25 2.4.3 VAKI Biomass Estimator Validation .......................................................................... 29 2.5 Discussion ........................................................................................................................... 30 v 2.5.2 Fish Growth ................................................................................................................. 30 2.5.1 Environmental Parameters ........................................................................................... 31 2.5.3 Biomass Estimator ....................................................................................................... 32 2.6 Conclusion .......................................................................................................................... 33 Chapter 3: The effects of salinity on the growth and feed conversion of coho and Atlantic salmon ...........................................................................................................................................34 3.1 Summary ............................................................................................................................. 34 3.2 Introduction ......................................................................................................................... 35 3.3 Methods............................................................................................................................... 38 3.3.1 Overview ...................................................................................................................... 38 3.3.2 Experimental Design .................................................................................................... 40 3.3.3 Water Testing & Analysis ............................................................................................ 42 3.3.4 Calculations.................................................................................................................. 43 3.3.4.1 Growth Rates ........................................................................................................ 43 3.3.4.2 Condition Factor ................................................................................................... 44 3.3.4.3 Feed Conversion ................................................................................................... 44 3.3.4.4 Muscle Water Content .......................................................................................... 45 3.3.5 Statistical Analysis ....................................................................................................... 45 3.4 Results ................................................................................................................................. 46 3.4.1 Water Parameters ......................................................................................................... 46 3.4.2 Coho Salmon 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