Fall 08 1 Contents ABSTRACT .................................................................................................................................... 4 1 INTRODUCTION .................................................................................................................... 6 2 THEORY ................................................................................................................................ 6 2.1 BIOLOGY ..................................................................................................................................... 6 2.1.1 Taxonomy ........................................................................................................................ 7 2.1.2 Dispersion ........................................................................................................................ 7 2.1.3 Description ....................................................................................................................... 8 2.1.4 Distribution ...................................................................................................................... 8 2.1.5 Life history ....................................................................................................................... 8 2.2 EXPLOITATION ............................................................................................................................. 9 2.2.1 Fisheries ........................................................................................................................... 9 2.2.2 Farming ........................................................................................................................... 9 2.3 PROCESSING .............................................................................................................................. 10 2.3.1 Slaughtering .................................................................................................................. 10 2.3.2 Filleting .......................................................................................................................... 10 2.3.2.1 Traditional cuts of Atlantic halibut ......................................................................................................... 10 2.3.2.2 Sashimi ................................................................................................................................................... 11 2.3.3 Storage .......................................................................................................................... 11 2.4 ANATOMY AND PHYSIOLOGY OF ATLANTIC HALIBUT RELEVANT TO QUALITY .......................................... 12 2.4.1 Blood circulation system ................................................................................................ 12 2.4.2 Guts ............................................................................................................................... 13 2.4.3 Muscles .......................................................................................................................... 13 2.4.3.1 Red muscles ............................................................................................................................................ 14 2.4.3.2 White muscles ........................................................................................................................................ 14 2.4.3.3 Intermediate muscle .............................................................................................................................. 15 2.4.4 Muscular structure ........................................................................................................ 15 2.5 COMPOSITION ........................................................................................................................... 17 2.5.1 Protein ........................................................................................................................... 17 2.5.2 Lipids .............................................................................................................................. 18 2.5.3 Effect of feed composition on farmed Atlantic halibut ................................................. 19 2.5.4 Lipid distribution ............................................................................................................ 19 2.5.5 Water ............................................................................................................................. 20 2.5.6 Carbohydrates ............................................................................................................... 21 2.5.7 Connective tissue ........................................................................................................... 21 2.5.8 Growth ........................................................................................................................... 22 2.6 BIOLOGICAL FACTORS INFLUENCING QUALITY .................................................................................. 23 2.6.1 Texture ........................................................................................................................... 23 2.6.2 Gaping ........................................................................................................................... 24 2.6.3 Water-holding capacity ................................................................................................. 24 2.6.4 Colour ............................................................................................................................ 25 3 MATERIALS AND METHODS ................................................................................................. 26 3.1 FISH ......................................................................................................................................... 26 3.2 MEASURING THE FISH ................................................................................................................. 26 2 3.3 FILLETING OF THE FISH AND PORTIONING ........................................................................................ 26 3.4 PREPARATION OF SASHIMI ........................................................................................................... 28 3.5 MEASURING THE SASHIMI ............................................................................................................ 29 3.6 DATA HANDLING AND STATISTICS .................................................................................................. 29 4 RESULTS ............................................................................................................................. 29 4.1 DEFINING FILLETS ....................................................................................................................... 29 4.2 YIELD AND PORTIONING OF WINTER HARVESTED ATLANTIC HALIBUT ................................................... 31 4.2.1 Yield ............................................................................................................................... 31 4.2.2 Fillets .............................................................................................................................. 31 4.2.3 Waste............................................................................................................................. 32 4.2.4 Body composition summary .......................................................................................... 33 4.2.5 Portioning the fillets ...................................................................................................... 35 4.3 YIELD AND PORTIONING OF SPRING HARVESTED ATLANTIC HALIBUT .................................................... 36 4.3.1 Yield ............................................................................................................................... 36 4.3.2 Fillets .............................................................................................................................. 37 4.3.3 Waste............................................................................................................................. 37 4.3.4 Portioning the fillets ...................................................................................................... 38 4.3.5 Sashimi .......................................................................................................................... 39 5 DISCUSSION ........................................................................................................................ 40 6 CONCLUSION ...................................................................................................................... 42 7 ACKNOWLEDGEMENTS ....................................................................................................... 43 8 REFERENCES........................................................................................................................ 44 8.1 WEBSITES ................................................................................................................................. 47 3 Abstract The aim of the study was to estimate the fillet yield (before and after skinning) and proximal composition in farmed Atlantic halibut (Hippoglossus hippoglossus) as well as portioning the fillets and calculate their corresponding yields. This was performed not only to assess fillet yields but also as an early feasibility study to see whether portioning them could increase the value of the fillets.