Summary

The skin colour of farmed snapper is markedly darker than wild caught fish and becomes even darker after harvesting. This difference has created problems with marketing whereby farmed snapper generally command lower market prices or reduced consumer acceptance. Two possible causes for skin darkening in farmed snapper are the colour of sea cages and exposure to high light intensity or ultraviolet (UV) light when grown in cages at the water’s surface.

In this study, dark coloured snapper were held in black or white cages in natural sunlight or inside a plastic shade-house with reduced natural lighting. Cage colour strongly affected the appearance of live snapper with lighter coloured fish achieved in white cages. Similarly, fish from white cages remained considerably lighter than those from black cages after harvest and storage on ice, although a slight darkening of the skin occurred with time. In contrast, snapper were unable to become lighter in the reduced light environment of the shade-house.

Fish from black and white cages were then presented to experienced wholesale fish buyers at two local fish markets for evaluation. Exposing snapper to white backgrounds had the potential to improve their wholesale market price by between 10 and 50%. Buyers indicated that greater consumer acceptance and wholesale prices are likely if the pink colouration of the skin can also be enhanced. In conclusion, snapper have a strong ability to modify skin colour to adapt to their surroundings. As such, fish should be grown in white cages or transferred to a white background prior to sale to potentially improve the profitability of snapper farming.