Protecting Atlantic Salmon Aquaculture Production from Climate-Related Challenges Through Diet Manipulation
The objective of this research was to determine:
(1) if additional dietary cholesterol could increase the thermal tolerance of female triploid Atlantic salmon (Salmo salar), thereby reducing the likelihood of mortality when exposed to rising ocean temperatures; and furthermore
(2) if this change in diet could improve fillet quality and fish health.
This research built upon the Burin Peninsula’s tradition of working on the sea, and was conducted in the hopes of ensuring that the region has future seafood-related employment and economic opportunities regardless of what environmental changes lie ahead. Thus, it fit well within the theme targeted by this funding opportunity ‘Ocean Health & Seafood Opportunities’.
With the threat of global climate change, and given that a mass mortality event has already occurred in this province, this study examined whether diet manipulation (increasing dietary cholesterol concentration) could be an effective tool that local salmon farmers could use to help mitigate these risks. Our results show that supplemental dietary cholesterol did not improve the upper thermal tolerance of Atlantic salmon as expected, and may actually negatively impact survival at high inclusion levels. Cholesterol was also not effective at preventing fillet ‘bleaching’, as pigmentation was lost at elevated temperatures regardless of dietary treatment. However, AquaBounty’s triploid salmon did not experience large numbers of mortalities until after 22°C, and this suggests that their production may be suitable in Placentia Bay and that ploidy might not influence their survival at high temperatures. The results of this study provide valuable information for companies like Grieg NL, and help ensure that salmon aquaculture in Newfoundland is sustainable.