Puget Sound, often perceived as a calm inland waterway, is home to a variety of shark species. While large, aggressive sharks frequently appear in media, those inhabiting these waters are generally not that type. Several shark species have adapted to the Sound’s unique environment, thriving beneath its surface, contributing to the region’s rich marine biodiversity.
Common Shark Species of Puget Sound
The Pacific Spiny Dogfish (Squalus suckleyi) is the most abundant shark in Puget Sound. These smaller sharks, typically 2.5 to 3 feet long but sometimes reaching 5 feet, are known for their schooling behavior and sharp spines in front of each of their two dorsal fins. They are long-lived, with some individuals reaching 100 years, and primarily feed on small schooling fish like herring and sandlance, as well as crustaceans.
The Bluntnose Sixgill Shark (Hexanchus griseus) is one of the largest species in the Sound, reaching up to 16 feet. These sharks typically prefer deep-water habitats but move into shallower waters at night for feeding. Puget Sound is thought to serve as an important nursery ground for young sixgill sharks, where they spend their formative years before migrating to deeper ocean environments. While impressive, they are not typically aggressive towards humans unless provoked.
Another large species, the Pacific Sleeper Shark (Somniosus pacificus), can grow considerably, with some reaching up to 24 feet. These sharks are sluggish and prefer deep, cold waters, making sightings in the Sound rare. They are opportunistic predators and scavengers, consuming a varied diet that includes bony fish, cephalopods, and carrion like marine mammals.
The Broadnose Sevengill Shark (Notorynchus cepedianus) is distinguished by its seven gill slits, two more than most other shark species. These sharks can grow to nearly 10 feet and are found in temperate waters globally, with confirmed presences in South Puget Sound. They are apex predators, feeding on a wide range of prey including fish, crustaceans, and marine mammals, and are often observed near seal haul-outs.
The Salmon Shark (Lamna ditropis) is a less common, transient visitor to Puget Sound, more frequently found in the open ocean. These sharks, growing up to 10 feet (typically 6.6 to 8.6 feet), resemble great white sharks. They are unique among fish species for their ability to maintain a core body temperature warmer than the surrounding water. While not permanent residents, some young salmon sharks may pass through the Sound as they migrate to feeding grounds further north.
Why Puget Sound is a Shark Habitat
Puget Sound provides an ideal environment for these shark species due to its unique physical and biological characteristics. The Sound features deep basins, averaging 450 feet deep and reaching over 900 feet in some areas, filled with cold, oxygen-rich waters that resemble open ocean conditions. These conditions suit many deep-dwelling species.
The Sound’s rich ecosystem supports an abundant food supply for sharks. It is home to over 200 fish species, including herring and salmon, and more than 3,000 invertebrate species like crabs and squid, which serve as primary food sources. Sharks function as apex predators within this food web, helping maintain ecological balance.
Puget Sound’s sheltered nature, compared to the exposed Pacific Ocean, offers protection from harsh conditions, particularly beneficial for certain life stages, such as the sixgill shark’s use of the Sound as a nursery. The Sound is also connected to the Pacific Ocean through the Strait of Juan de Fuca and Strait of Georgia, facilitating species movement. This connectivity supports diverse shark populations.
Encountering Sharks in Puget Sound
Encounters with sharks in Puget Sound are exceedingly rare, especially with larger, deep-dwelling species. Most of the sharks inhabiting these waters are naturally shy and tend to avoid human interaction. Prevalent species, such as the Spiny Dogfish and Sixgill Shark, are not considered a threat to humans.
Historical records indicate unprovoked shark encounters in Washington state are extremely infrequent. Since 1837, only two incidents have been recorded, both occurring on the outer coast and resulting in non-fatal outcomes. Most reported interactions involve divers observing sharks or fishermen accidentally catching them, rather than casual swimmers. If an unlikely encounter occurs, maintain a respectful distance and avoid provoking the animal.