Researchers have made the landmark scientific discovery of two unique shark species in Puget Sound, one of which is critically endangered.
Researchers from Oregon State University have scientifically documented two different shark species in Puget Sound for the first time, one being critically endangered.
The identification of the broadnose sevengill shark and the endangered soupfin shark in the sound, part of the southern Salish Sea, suggests shifts in an inland waterway that is economically, culturally, and ecologically significant, as noted by biologists in OSU’s Big Fish Lab.
The Salish Sea distinguishes northwest Washington from Vancouver Island in British Columbia. This extensive water body, spanning 6,500 square miles, includes Puget Sound in Washington. The sharks were found near Olympia, close to the southern edge of the sound.
Taylor Chapple, an assistant professor at Oregon State’s College of Agricultural Sciences, along with graduate students Jessica Schulte and Ethan Personius, have documented the broadnose sevengill and soupfin sharks in studies published in Frontiers in Marine Science.
They collaborated with colleagues from NOAA’s National Marine Fisheries Service and the Washington Department of Fish and Wildlife to verify that the broadnose sevengill, an apex predator capable of reaching nearly 10 feet in length, is now present in the heavily urbanized South Puget Sound.
“Recognizing the sevengill’s presence in this new environment is vital for understanding the food webs of the Salish Sea and underscores the necessity for ongoing monitoring and research, particularly regarding their interactions with other vulnerable species like salmon,” stated Schulte, who is the lead author on the sevengill study.
Broadnose sevengill sharks are named for their distinctive two extra gill slits compared to most sharks. They have a varied diet that includes fishes (like rays and other sharks), crustaceans, and even marine mammals. This species inhabits temperate waters around the globe, from southern Alaska to Baja California along the West Coast of North America.
Before 2021, only one sevengill shark had ever been recorded in the Salish Sea at Point Roberts, Washington, near the Canadian border. However, anecdotal evidence in August 2021 suggested multiple catches in South Puget Sound.
During 10 days of field research in 2022 and 2023, the team caught nine sevengills, well over 190 miles from their previously known range. Out of these, eight were males, the largest measuring just under 7 feet, and the single female was approximately 4 feet, 6 inches long.
“Our ongoing studies on this species in Oregon and Washington will help us better understand its role within our important marine ecosystems,” Schulte remarked.
Similar findings were shared regarding the soupfin shark, according to Personius, who leads that specific study. The soupfin shark is the largest type of hound shark, growing as long as 6 1/2 feet, and is named for its use in making shark fin soup.
“Soupfin sharks faced severe overfishing in the 1930s and 1940s, particularly for their vitamin A-rich livers,” Personius noted. “Even with reduced fishing pressures, the population has struggled to rebound and is currently being considered for federal protection under the Endangered Species Act.”
Like the broadnose sevengill shark, the soupfin shark thrives in temperate waters worldwide and is also a top predator within its ecosystems, preying on cephalopods and various fish species. Soupfin sharks are also powerful swimmers, known to migrate over distances greater than 1,000 miles.
During the field work linked with the sevengill research, the scientists captured one soupfin shark, a male measuring just over 5 feet.
“The Salish Sea has seen significant shifts in species populations and diversity amidst industrial growth and considerable habitat degradation,” Personius remarked. “The presence of soupfin sharks may be linked to climate change and variations in prey availability.”
After the marine heat wave known as “The Blob” in 2014-15, anchovies became a dominant forage fish species in the Salish Sea, a species that was historically rare. Soupfin sharks are known predators of anchovies.
Graduate student Maddie English is a co-author on the soupfin shark study along with NOAA Marine Fisheries Service and Washington Department of Fish and Wildlife scientists. Research associate Alexandra McInturf also contributed to the sevengill study.
