I used physiological stress as in indicator of welfare of adult Atlantic salmon during transport onboard a commercial live-haul vessel, the Sterling Carrier under actual operational conditions. This state-of-the-art vessel incorporates both flow-thru (open-hold) and re-circulating (closed-hold) live-hold configurations to safely transport fish under diverse environmental conditions. Measurements of bulk oxygen uptake rates (bulk MO₂) for fish masses ranging from 20 to 40 tons during open-hold transports (n=89) revealed a slightly elevated bulk MO₂ that was comparable to routine bulk MO₂ measured in adult Atlantic salmon, Salmo salar held in large tanks and also to resting MO₂ of individual Pacific salmonids measured in swim-respirometers. These results indicate a low level of stress, and suggest that open-hold live-haul transport aboard the Sterling Carrier does not compromise fish welfare. While closed-hold transport protects fish from poor environments, water quality conditions progressively deteriorate as respiratory CO₂ accumulates in the water. I measured water CO₂ and pH changes during closed-hold transport experiments and used these data to model CO₂ and pH changes over a wide range of transport conditions. Model outputs demonstrated that the partial pressure of CO₂ (Pco₂) could accumulate to potentially deleterious levels (>10 torr) in 20-158 min depending on fish stress levels and loading densities. These data may be useful in estimating transport lengths possible under Pco₂ thresholds, which are presently lacking for live-haul transport. The effects of 3-h and 24-h exposures to elevated water Pco₂ (hypercarbia) on blood pH and post-mortem flesh quality were also measured in adult Atlantic salmon. While elevated water Pco₂ disturbed blood pH as predicted, there were minimal effects on flesh quality based on rigor mortis and flesh pH assessments, which were further reduced if fish were allowed to recover for 24-h after a hypercarbic exposure. This study provides novel insights into a) current techniques of assessing fish welfare during live-haul transport, b) limitations associated with transporting fish under re-circulating conditions, and c) effects of elevated Pco₂ on flesh quality indicators in adult Atlantic salmon.

I used physiological stress as in indicator of welfare of adult Atlantic salmon during transport onboard a commercial live-haul vessel, the Sterling Carrier under actual operational conditions. This state-of-the-art vessel incorporates both flow-thru (open-hold) and re-circulating (closed-hold) live-hold configurations to safely transport fish under diverse environmental conditions. Measurements of bulk oxygen uptake rates (bulk MO₂) for fish masses ranging from 20 to 40 tons during open-hold transports (n=89) revealed a slightly elevated bulk MO₂ that was comparable to routine bulk MO₂ measured in adult Atlantic salmon, Salmo salar held in large tanks and also to resting MO₂ of individual Pacific salmonids measured in swim-respirometers. These results indicate a low level of stress, and suggest that open-hold live-haul transport aboard the Sterling Carrier does not compromise fish welfare. While closed-hold transport protects fish from poor environments, water quality conditions progressively deteriorate as respiratory CO₂ accumulates in the water. I measured water CO₂ and pH changes during closed-hold transport experiments and used these data to model CO₂ and pH changes over a wide range of transport conditions. Model outputs demonstrated that the partial pressure of CO₂ (Pco₂) could accumulate to potentially deleterious levels (>10 torr) in 20-158 min depending on fish stress levels and loading densities. These data may be useful in estimating transport lengths possible under Pco₂ thresholds, which are presently lacking for live-haul transport. The effects of 3-h and 24-h exposures to elevated water Pco₂ (hypercarbia) on blood pH and post-mortem flesh quality were also measured in adult Atlantic salmon. While elevated water Pco₂ disturbed blood pH as predicted, there were minimal effects on flesh quality based on rigor mortis and flesh pH assessments, which were further reduced if fish were allowed to recover for 24-h after a hypercarbic exposure. This study provides novel insights into a) current techniques of assessing fish welfare during live-haul transport, b) limitations associated with transporting fish under re-circulating conditions, and c) effects of elevated Pco₂ on flesh quality indicators in adult Atlantic salmon.

I used physiological stress as in indicator of welfare of adult Atlantic salmon during transport onboard a commercial live-haul vessel, the Sterling Carrier under actual operational conditions. This state-of-the-art vessel incorporates both flow-thru (open-hold) and re-circulating (closed-hold) live-hold configurations to safely transport fish under diverse environmental conditions. Measurements of bulk oxygen uptake rates (bulk MO₂) for fish masses ranging from 20 to 40 tons during open-hold transports (n=89) revealed a slightly elevated bulk MO₂ that was comparable to routine bulk MO₂ measured in adult Atlantic salmon, Salmo salar held in large tanks and also to resting MO₂ of individual Pacific salmonids measured in swim-respirometers. These results indicate a low level of stress, and suggest that open-hold live-haul transport aboard the Sterling Carrier does not compromise fish welfare. While closed-hold transport protects fish from poor environments, water quality conditions progressively deteriorate as respiratory CO₂ accumulates in the water. I measured water CO₂ and pH changes during closed-hold transport experiments and used these data to model CO₂ and pH changes over a wide range of transport conditions. Model outputs demonstrated that the partial pressure of CO₂ (Pco₂) could accumulate to potentially deleterious levels (>10 torr) in 20-158 min depending on fish stress levels and loading densities. These data may be useful in estimating transport lengths possible under Pco₂ thresholds, which are presently lacking for live-haul transport. The effects of 3-h and 24-h exposures to elevated water Pco₂ (hypercarbia) on blood pH and post-mortem flesh quality were also measured in adult Atlantic salmon. While elevated water Pco₂ disturbed blood pH as predicted, there were minimal effects on flesh quality based on rigor mortis and flesh pH assessments, which were further reduced if fish were allowed to recover for 24-h after a hypercarbic exposure. This study provides novel insights into a) current techniques of assessing fish welfare during live-haul transport, b) limitations associated with transporting fish under re-circulating conditions, and c) effects of elevated Pco₂ on flesh quality indicators in adult Atlantic salmon. / Science, Faculty of / Zoology, Department of / Graduate

Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare.

Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare.

Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare. / Land and Food Systems, Faculty of / Graduate