National Marine Mammal Laboratory Report for Alaska Fisheries Science Center Quarterly Report for October-December 1997

Killer Whales Observed in Dyes Inlet

During late October and early November of 1997, 19 killer whales were observed feeding on chum salmon in the Dyes Inlet area in southern Puget Sound, Washington. The 19 whales were identified as members of the well-known resident “L” pod. The occurrence of whales in this protected inland area is not common, and the event lured hundreds of spectators each day. After 2-3 weeks, the sinuous nature of the inlet, with two overhead bridges spanning the narrowest parts, and the large number of whale-watching boats caused concern about what appeared to be the reluctance of the whales to leave the area.

On 19 November 1997, members of the National Marine Mammal Laboratory (NMML) visited Dyes Inlet to monitor the killer whales and assess the situation. Reports that day indicated that the whales had attempted to swim under the bridge into the open waters of Puget Sound. As the whales approached the bridge, they abruptly turned around and headed back into the inlet. Within an hour, the whales again changed direction and started heading back towards the bridge.

In a vessel that allowed clear observation, the NMML team followed the animals at a considerable distance behind and at a speed no faster than the whales were swimming. As the whales approached the bridge they began to slow down. Some spyhopped, and some turned on their sides as if to look up at the bridge. Yet another time, they made a 180-degree turn and again headed straight back down the narrows into the inlet. After approximately 30 minutes, the whales turned to head for the bridge again. Unlike the previous passes, this time the whales appeared to be swimming faster.

The group of 19 killer whales broke into three smaller groups. The lead of these three groups was observed swimming rapidly under the bridge. The second group slowed down for an instant as they approached the bridge, then increased speed and moved forward under the bridge. There were two remaining whales in the final group that stopped by the bridge pilings. Our observations indicated that they were an adult female and a juvenile. The NMML vessel continued forward under the bridge along with the second group of whales then, reduced speed to monitor the two whales that were lagging behind.

Within a few minutes, a large, male killer whale left the second group and moved back toward the bridge and began breaching. It appeared that the behavior of the male (identified as the son of the adult female that was lagging behind) prompted the female and juvenile to join the other whales. All whales were now past the first of two bridges. As the entire group of whales approached the second bridge, they continued swimming into the open Sound with no hesitation. As they reached open water, they were observed to exhibit fast, subsurface swimming indicative of feeding. It was agreed by all scientists and researchers making observations in the area that the whales left on their own volition. The whales left with the tide, on a stormy day, with relatively few boats noted in the area.

By Marilyn Dahlheim.