Orcas are present in Puget Sound, with different populations exhibiting distinct behaviors and ecological roles. Understanding these differences clarifies their relationship with the Puget Sound ecosystem.
Orca Presence and Varieties
Puget Sound is home to several distinct types of orcas. The most well-known are the Southern Resident Killer Whales (SRKWs), followed by the Transient, or Bigg’s, Killer Whales. Offshore Killer Whales are also recognized but rarely venture into the sound’s inner reaches.
Southern Resident Killer Whales consist of three distinct pods: J, K, and L. These fish-eating orcas primarily consume salmon, with a strong preference for Chinook salmon. They historically spend several months each summer and fall within Puget Sound and the wider Salish Sea, though their seasonal presence has shifted to increased fall and winter presence.
In contrast, Bigg’s Killer Whales are marine mammal-eaters, preying on seals, sea lions, porpoises, and other marine mammals. Unlike residents, Bigg’s Killer Whales roam in smaller groups and are increasingly sighted in Puget Sound, with their population thriving alongside their prey. Observations in 2023 showed a record number of Bigg’s Killer Whale sightings. These two ecotypes do not interbreed and exhibit distinct social structures and hunting behaviors.
Ecological Significance of Puget Sound
Puget Sound serves as an important habitat for various orca populations, particularly Southern Resident Killer Whales. The sound is important as a feeding ground and migratory corridor, providing access to essential prey. Chinook salmon, a primary food source, are high-caloric and fatty, making them an ideal meal for these large predators, especially for sharing within their pods.
The geographical features of Puget Sound, including rivers and marine passages, support the salmon populations orcas rely on. Chinook salmon from various river systems contribute to the orcas’ diet throughout the year. The availability of these salmon stocks is directly linked to the health and survival of the Southern Residents. The sound’s sheltered waters also offer a contained environment where prey can be concentrated, making it a valuable foraging area.
Population Health and Protection Efforts
The Southern Resident Killer Whale population in Puget Sound faces challenges, with their status listed as endangered. As of July 1, 2024, their population numbered only 73 individuals, a decline from 75 in 2023. This decline is primarily attributed to insufficient prey (Chinook salmon), noise and disturbance from vessel traffic, and toxic contaminants.
Prey scarcity impacts the orcas’ health and reproduction. Chinook salmon populations have declined from historical levels due to habitat destruction. When food is scarce, orcas metabolize blubber reserves, releasing accumulated pollutants. Marine noise from vessels interferes with echolocation, making it difficult for them to find prey and communicate, forcing them to expend more energy.
Various conservation and recovery efforts are underway to address these threats. Government agencies, non-profits, and local communities are implementing strategies to increase Chinook salmon abundance through habitat restoration and management. Measures are also in place to reduce vessel disturbance, including new boating rules requiring a minimum distance of 1,000 yards from Southern Resident Killer Whales in Washington waters as of January 1, 2025. Efforts also focus on reducing contaminants like polychlorinated biphenyls (PCBs), which accumulate in the food chain and impact orca health. These integrated approaches aim to support the long-term survival and recovery of this population.