Oregon State University researchers have confirmed the presence of two distinct shark species, including the critically endangered soupfin shark, in Puget Sound in the southern portion of the Salish Sea. This discovery, made by members of OSU’s Big Fish Lab, suggests significant changes in the inland waterway that is economically, culturally, and ecologically valuable. The sharks were found close to Olympia near the sound’s southernmost point, indicating a shift in their habitat range.
The broadnose sevengill shark and the endangered soupfin shark were documented by Assistant Professor Taylor Chapple and graduate students Jessica Schulte and Ethan Personius in research papers published in Frontiers in Marine Science. Collaborating with partners at NOAA’s National Marine Fisheries Service and the Washington Department of Fish and Wildlife, the researchers were able to confirm the presence of these apex predators in South Puget Sound. The broadnose sevengill shark, known for its large size and broad diet, is now inhabiting heavily urbanized South Puget Sound, highlighting the need for continued monitoring and research.
Broadnose sevengill sharks, named for their two additional gill slits, eat a variety of prey including fish, crustaceans, and marine mammals. They are found in temperate waters worldwide and in the waters off the west coast of North America from southern Alaska to Baja California. Similarly, soupfin sharks, the largest species of hound shark, are top predators in their ecosystems, feeding on cephalopods and various fish species. Despite being exploited in the past, they have struggled to recover, leading to considerations for federal protection.
Anecdotal reports in 2021 signaled an increase in sevengill shark sightings in South Puget Sound, prompting further investigation by the researchers. Over 10 days of field work in 2022 and 2023, nine sevengill sharks were caught, representing an expansion of their documented range by over 190 miles. The majority of the sharks caught were males, with the largest measuring nearly 7 feet in length. This new data will help in understanding the role of these species in marine ecosystems and the impacts of their presence in the Salish Sea.
The appearance of soupfin sharks in the Salish Sea may be a result of climate change and changes in prey availability following the extreme marine heat wave known as “The Blob” in 2014-15. This event led to shifts in species abundance and composition in the area, with anchovies becoming a dominant forage fish species. It is believed that soupfin sharks, known predators of anchovies, have been drawn to the area due to the increased availability of their preferred prey. Further research and monitoring are essential to understanding the implications of these changes.
Graduate student Maddie English, along with scientists from NOAA Marine Fisheries Service and the Washington Department of Fish and Wildlife, contributed to the research on soupfin sharks. Research associate Alexandra McInturf also played a role in the sevengill study, highlighting the collaborative efforts involved in studying these species. Continued research on both the broadnose sevengill and the soupfin sharks in Oregon and Washington waters will provide valuable insights into their populations, behaviors, and roles within the marine ecosystems of the Salish Sea.