Toward Improved Public Confidence in Farmed Fish: A Canadian Perspective on Fish Welfare during Marine Transport

One of the advantages of farmed salmon is the consistent nature of the product and its availability. Because of the remote locations of salmon farms in British Columbia (BC), Canada, providing the freshest salmon products on a daily basis and in a cost-effective manner requires regular transport of live, market-sized adult fish at very high densities from farm sites to processing plants. Live-hauling also occurs annually when salmon smolts are moved to the farms from freshwater hatcheries and when fish are moved among farms. This article has two parts. The first part considers recent published works assessing Atlantic salmon, Salmo salar, welfare during live-haul transport between commercial aquaculture sites in BC, Canada, trips that can last for 2-12 h. These assessments involved novel methodologies, which are highlighted here. The results show that while juvenile and adult Atlantic salmon are stressed during loading into a live-haul vessel, open-hold transport in a state-of-the-art vessel promotes fish recovery, thereby alleviating some of the concerns regarding fish welfare during high-density transport. The second part of the article presents novel unpublished data on the effects on the flesh quality of Atlantic salmon of high carbon dioxide concentrations, levels that simulate those that might be encountered during closed-hold transport.