. 2020 Feb 28;7:57. doi: 10.3389/fvets.2020.00057

Table 1.

Two cases concerning different levels of exposure to vessel traffic for individuals belonging to a hypothetical Southern Resident killer whale (SRKW) pod.

Case 1	Case 2
A SRKW 20-year-old female orca with a 2-year-old calf is a member of pod X that has been present in the inshore waters for ~50% of the time in the past year. On a day in early September, this focal female has been swimming in a subgroup with 15 companions. The other subgroups from her pod are <1 km away and swimming in a similar direction. By dusk on this day, which has been typical for this season, the subgroup has been accompanied continuously by an average of 12 vessels, with peaks of 20 vessels for a 2-h period mid-morning and a 2-h period mid-afternoon. Half of the vessels were motorized, and all remained more than 200 m from the group, most at a distance of more than 400 m. Kayaks and sail boats comprised the other observing vessels. At peak mid-morning and afternoon viewing times, background noise approached 100 dB. The focal female performed no surface active behavior in response to the vessels, but her swimming path has been more erratic during the day and she has expended 2% more energy/h during daytime periods of boat presence than during early morning or night when vessels were absent. She has remained with the subgroup all day and reunited with the rest of the pod at night.	A SRKW 20-year-old female orca with a 2-year-old calf is a member of pod X that has been present in the inshore waters for ~80% of the time in the past year. On a day in early September, this focal female has been swimming in a subgroup with 15 companions. The other subgroups from her pod are <1 km away and swimming in a similar direction. By dusk on this day, which has been typical for this season, the subgroup has been observed continuously by an average of 24 vessels, with peaks of 40 vessels for a 2-h period mid-morning and a 2-h period mid-afternoon. Three-quarters of the vessels were motorized. Of these, most remained at a distance of 200 m from the subgroup, but 10% were observed to break guidelines and approached the whales to within 90 m. Another 10% were observed idling in the path of the whales with the intention of getting a closer view as the whales approached them. At peak mid-morning and afternoon viewing times, background noise approached 140 dB. The focal female was observed performing tail slapping behavior on six occasions. On one occasion, the subgroup split into two further subgroups, and the female was briefly separated from her calf. She and her calf have become separated from the subgroup twice when following an erratic path to avoid a boat approaching directly head-on. The female has expended 5% more energy/h during the daytime periods of boat presence than during early morning or night when vessels were absent. She has remained with the subgroup for most of the day and reunited with the rest of the pod at night.

Case 1

Case 2

A SRKW 20-year-old female orca with a 2-year-old calf is a member of pod X that has been present in the inshore waters for ~50% of the time in the past year. On a day in early September, this focal female has been swimming in a subgroup with 15 companions. The other subgroups from her pod are <1 km away and swimming in a similar direction. By dusk on this day, which has been typical for this season, the subgroup has been accompanied continuously by an average of 12 vessels, with peaks of 20 vessels for a 2-h period mid-morning and a 2-h period mid-afternoon. Half of the vessels were motorized, and all remained more than 200 m from the group, most at a distance of more than 400 m. Kayaks and sail boats comprised the other observing vessels. At peak mid-morning and afternoon viewing times, background noise approached 100 dB. The focal female performed no surface active behavior in response to the vessels, but her swimming path has been more erratic during the day and she has expended 2% more energy/h during daytime periods of boat presence than during early morning or night when vessels were absent. She has remained with the subgroup all day and reunited with the rest of the pod at night.

A SRKW 20-year-old female orca with a 2-year-old calf is a member of pod X that has been present in the inshore waters for ~80% of the time in the past year. On a day in early September, this focal female has been swimming in a subgroup with 15 companions. The other subgroups from her pod are <1 km away and swimming in a similar direction. By dusk on this day, which has been typical for this season, the subgroup has been observed continuously by an average of 24 vessels, with peaks of 40 vessels for a 2-h period mid-morning and a 2-h period mid-afternoon. Three-quarters of the vessels were motorized. Of these, most remained at a distance of 200 m from the subgroup, but 10% were observed to break guidelines and approached the whales to within 90 m. Another 10% were observed idling in the path of the whales with the intention of getting a closer view as the whales approached them. At peak mid-morning and afternoon viewing times, background noise approached 140 dB. The focal female was observed performing tail slapping behavior on six occasions. On one occasion, the subgroup split into two further subgroups, and the female was briefly separated from her calf. She and her calf have become separated from the subgroup twice when following an erratic path to avoid a boat approaching directly head-on. The female has expended 5% more energy/h during the daytime periods of boat presence than during early morning or night when vessels were absent. She has remained with the subgroup for most of the day and reunited with the rest of the pod at night.

The cases were scored using the refined welfare assessment tool for wild cetaceans (WATWC). The assessors had access to an instruction sheet, additional referenced background information (Supplementary Materials), the cetacean-specific FDM (Figure 1), and a scoresheet (Figure 2, and available on request).