Ignorance or even outright fear of sharks is turning to fascination in the Puget Sound region, where exciting discoveries are gaining public attention. More people are beginning to understand the true nature of these ancient and perplexing creatures, according to regional shark experts.
Which shark species might be hiding in the nooks and crannies of the Salish Sea is not yet fully understood, despite years of biological surveys and general observations of marine life. But new discoveries, helped along by new technologies, are putting pieces of the puzzle together.
Just this year, researchers reported the discovery of what might be a haven for broadnose sevengill sharks in South Puget Sound. In a collaborative research project, 16 of these sharks, almost never before seen in Puget Sound, were captured and released in and around Hammersley Inlet, based on information from a local fisherman. Until that time, only one broadnose sevengill shark had ever been confirmed in Puget Sound, and that one was caught just south of the Canadian border.
Fish biologist Lisa Hillier of the Washington Department of Fish and Wildllife with a broadnose sevengill shark captured in Puget Sound. Photo: Jessica Schulte/OSU
During the process of capturing and releasing sevengills in South Sound, the research team caught another species of shark that came as an even bigger surprise. Called a soupfin or tope shark, this rare species is currently under review nationwide for placement on the federal Endangered Species List. Until now, this species had never been formally documented anywhere in Puget Sound.
These discoveries have further escalated public interest in the sharks of Puget Sound, according to Dayv Lowry, a marine biologist with the National Oceanic and Atmospheric Administration who has spent years honing his interest in sharks. His personal fascination began at the age of 8 when he first gazed upon sharks swimming in the National Aquarium of Baltimore, and his passion for sharks has grown with each new discovery.
Through many years of working with marine life in Puget Sound, Lowry has noticed that people seem to have an unusual curiosity when they learn that sharks are living nearby. “Many people find it surprising that they are even here,” he noted, adding that increasing public awareness may help bring better protections for sharks and their habitats.
At least nine species of sharks are now known to exist — at least on occasion — in Puget Sound. One species — the Pacific spiny dogfish shark — is quite common, while several species are seen only rarely. Scientists aren’t sure if these “rare species” have somehow eluded human contact or if these sharks simply don’t come around very often. Reported encounters — which often involve catching sharks with sport or commercial fishing gear — are more frequent along the Washington Coast and down into California.
Shark species known to exist in Puget Sound
- Basking shark (Cetorhinus maximus)*
- Bluntnose sixgill shark (Hexanchus griseus)
- Broadnose sevengill shark (Notorynchus cepedianus)*
- Brown cat shark (Apristurus brunneus)
- Common thresher (Alopias vulpinus)*
- Leopard shark (Triakis semifasciata)*
- Pacific spiny dogfish (Squalus suckleyi)
- Salmon shark (Lamna ditropis)*
- Soupfin shark (Galeorhinus galeus)*
*Species considered rare in Puget Sound at this time
When it comes to the spiny dogfish, more than a few salmon fishermen know something about these fish, which can grow to about four feet in Puget Sound and will gladly take the bait at the end of a fishing line. The few anglers who actually target dogfish may tell you that, properly prepared, they make for a nice meal of fish and chips.
Formal studies of sharks in Puget Sound remain limited. Many of the scientific investigations in our inner waterways have focused on salmon, killer whales and other threatened and endangered species, along with fish considered important to sport and commercial fishermen. Even so, scientific curiosity about local sharks has been growing. Recent discoveries could bring even greater interest — and funding — to studies of Puget Sound sharks, which can play an important or even critical role in the overall food web, a role that may have been underestimated for years, according to Lowry and other shark experts.
Managing uncertain shark populations in Puget Sound through regulations, education and research is a major challenge for state agencies, said Lisa Hillier, a groundfish biologist for the Washington Department of Fish and Wildlife who has become the agency’s designated authority on sharks. The goal, she said, is to protect vulnerable shark species without unwarranted fishing rules. That’s not easy when so many sharks remain out of sight, if not out of mind.
Sharks and their ancient ancestors — characterized with spines of flexible cartilage rather than hard bone — date back more than 450 million years, long before dinosaurs roamed the Earth. Another striking characteristic is that most female sharks, unlike other fish, carry fertilized eggs in their bodies, giving birth to baby sharks that swim and forage on their own. Today, more than 500 species of sharks worldwide have been identified and named. Of those, about 100 are known to range into U.S waters, with 13 found off the coast of Washington state and nine seen in Puget Sound.
Tracking their movements
In contrast to killer whales, which are air-breathing mammals, sharks are fish that get their oxygen from the water, so most are not easily observed at the surface via a boat or aircraft. A shark’s migration pattern, if any, has been a challenge to figure out — although there is growing evidence that some ocean-going species may use Puget Sound as a nursery for their early years before migrating to the ocean. Even the spiny dogfish appears to vacate Puget Sound for a few months each year.
Traditional studies of shark movements involved capturing a shark, attaching a visible tag with a unique identifier, and releasing the animal with the hope that someone else will catch the shark in the future. In this way, experts figured out that most species of sharks range widely, including those that travel north and south along the West Coast.
Now, with more advanced equipment, including implanted acoustic tags, researchers can track sharks for years with much greater precision and no need to recapture them. Unique transmissions from acoustic tags are picked up by receivers installed underwater at various locations to reveal the route that a particular shark is traveling.
Another type of tag, designed to detach from the shark after a specified time, uses sophisticated technology to measure and record every twist and turn taken by a swimming shark as it chases its prey. This device can measure depth, temperature and other water parameters. Some tags are even equipped with video to provide an idea of what a shark sees as it goes about its day. When this tag detaches, it floats to the surface and sends out a radio signal to satellites, allowing researchers to recover the tag along with its extensive data collection.
Lisa Hillier (WDFW), foreground, and Jess Schulte (OSU) assess a broadnose sevengill shark captured in South Puget Sound (left). The shark will be fitted with an acoustic tag (right) to track its movements after it is released back into the water. Photos: Kate Olson/WDFW
Taylor Chapple, a leading expert on shark tagging who has studied shark populations throughout the world, says today’s high-tech instruments have opened the door to new knowledge about these fascinating creatures.
“Sometimes we make assumptions with limited data,” said Chapple, who heads the Big Fish Lab at Oregon State University. “We used to think that sharks generally cruised up and down the West Coast, but now we know that isn’t always true.”
For example, a white shark (better known to the public as a great white shark) was tagged in Central California in 2007. It was found in the same spot one year later. While one could surmise from this finding that the shark never strayed far from this one location, that conclusion would be wrong, Chapple said. The truth is that the animal swam out to Hawaii and back on a zigzag course, as revealed by a year’s worth of biophysical data recorded during the shark’s travels.
One of the big questions now facing researchers is how climate change could be affecting the food web in Puget Sound, increasing or decreasing the survival of various species while attracting new species to the region. Ongoing research on sharks could provide critical information about species interactions.
“We want to tie these findings into the broader ecology of Puget Sound,” Lowry said of the recent shark discoveries. “How many sharks are there? How long have they been here? What are they eating, and are they eating enough to affect the overall ecosystem? Sharks are also prey; and some get eaten by orcas; so how does that affect the ecosystem? These are questions we would like to answer.”
Sharks make a splash
Connor Seifert was a newcomer to shark fishing in June 2021, when he caught a nine-foot shark that confounded experts and soon upended common assumptions about sharks in Puget Sound.
Although Seifert had grown up fishing for lake species, such as trout, he had only recently turned to catching sharks, focusing first on Pacific spiny dogfish, a smallish shark common to Puget Sound.
“A local fisherman told me about a good spot to fish for Pacific spiny dogfish,” he said.
Going to that spot near the town of Shelton, he chose a shoreside location and cast his line into about 20 to 30 feet of water.
“I was using salmon gear then, not really knowing what I was doing,” he recalled. “The first one I caught was a dogfish, almost 20 pounds. I caught three dogfish and then a female soupfin (shark), which jumped out of the water.”
From a quick glance, Seifert estimated that the soupfin was about 6 feet long. As the shark fought back on the line, it cut through the steel leader with its sharp teeth. “I was excited to catch something that big,” Seifert said, “but it got away.”
Soupfin sharks in South Puget Sound would later astonish shark scientists, but it was Seifert’s next catch that brought authorities to his door and led biologists into a new line of investigations. After the soupfin escaped, Seifert hooked into another whopper and was challenged to reel in the big fish with lighter tackle than he really needed for the job.
“I was nervous,” Seifert said, describing how the shark changed directions as he played out his line. The fish turned back and forth loosely like a big snake. At first, Seifert thought he had hooked into a sixgill shark, a species that suddenly appeared in large numbers in Puget Sound during the 1990s. But the shark he finally brought to shore had seven gill slots, not six. Proudly, he posted a photo on Facebook, showing himself with his big shark on the beach, before he released it.
Someone noticed the Facebook photo and, assuming that it was a sixgill shark, contacted state fisheries officers. Under Washington state fishing rules, it is illegal to remove sixgill sharks from the water because of the risk of killing them. Also, one cannot directly target sixgill or sevengill sharks, which must be released. An officer from the Washington Department of Fish and Wildlife visited Seifert at his home to collect information about the rare sevengill shark. Seifert was not in any legal trouble, because he had followed the rules, but his catch brought all sorts of attention.
Biologist Dayv Lowry, who had been called on to identify the shark in Seifert’s picture, realized that he was looking at a shark never before reported in South Puget Sound. Lowry confirmed the fishing spot by visiting the site and comparing it with the background scene in the photo. He and other shark experts wanted to investigate the mysterious catch of at least one broadnose sevengill shark swimming in South Puget Sound.
For his part, Seifert continues to fish for sharks. He says he has caught and released sevengills at least 70 times, although some may have been caught more than once. He also has taken about a dozen soupfins, which are legal to keep and eat under current rules.
Seifert has become an expert at landing sharks and rays, as well as sturgeon and other interesting freshwater fish. He hopes to turn his pastime into a fishing-guide business, helping anglers catch unusual fish in both fresh and saltwater.
Studying sevengill sharks
Reports of Seifert’s sevengill shark grabbed the attention of shark experts throughout the region. At the time, many believed it was probably a lone shark that had gotten lost and ended up in Hammersley Inlet by chance. But there was no escaping the fact that one sevengill — and possibly more — had been caught nearly 200 miles (by water) from the Pacific Ocean. NOAA’s Dayv Lowry, who previously worked for the Washington Department of Fish and Wildlife, discussed the finding with Lisa Hillier, WDFW’s leading shark biologist.
Also brought into the research discussion was Jess Schulte, a graduate student at Oregon State University who was already studying sevengill sharks in Willapa Bay on Washington’s coast under the guidance of Taylor Chapple. Together, this ad hoc team decided to take a boat into Hammersley Inlet in an uncertain search for sharks in the spring of 2022.
“None of us expected to find anything,” said Schulte, “because we didn’t think any sevengills were there. We thought it was probably a lost sevengill that was caught by Connor.”
Hammersley Inlet is a nine-mile-long natural channel connecting Shelton’s Oakland Bay with the main part of Puget Sound. Tides rush through the narrow, winding channel — which averages just a quarter mile across — to create riverlike conditions.
Map showing the previously reported distribution of the soupfin shark (orange), and the previously reported location (diamond) and recent capture location (star) of the soupfin and broadnose seven gill sharks in the Salish Sea. Insets zoom in on sub-basins and recent capture sites in Hammersley Inlet and Oakland Bay. Map: Personius et al. 2024
On the first trip out, on May 23, 2022, the research team was surprised to catch two sevengill sharks, a seven-foot male and a 4.5-foot female. Acoustic tags were inserted into both animals to track them for up to 10 years. As fate would have it, the male shark was detected nearly a year later, on April 7, 2023, by a receiver just off Coos Bay in Oregon, a swimming distance of more than 500 miles. Indeed, at least some of these sharks were great travelers.
After that first catch of two sevengills, the group returned two weeks later and captured two more males in Hammersley Inlet.
During the following summer and fall, the team made eight trips to Hammersley. In June 2023, three males were captured, followed by two males in August. None were caught in September, October or November of 2023, supporting the idea that sevengills may be migrating elsewhere in winter, as other shark species are known to do. More detailed information can be expected when Schulte and her fellow researchers analyze tracking data generated from the embedded tags.
Returning this year, another seven sevengill sharks — four males and three females — were caught during four trips during the summer. One of these was a small juvenile female, which raised the alluring prospect that sevengill sharks could be giving birth in this area of South Puget Sound.
“It was so exciting,” said Schulte of the youngster. “At first, we thought it was a spiny dogfish, because it was so little. You could literally lift it with one hand. It was beautiful to see such a diversity in age.”
Schulte, who grew up in Florida, became interested in food-web interactions at the University of Florida at Gainesville, where she graduated in 2013. As an intern, she helped maintain the International Shark Attack File at Florida’s Museum of Natural History. Schulte continued her research on aquatic food webs at the Wetland and Aquatic Research Center in Florida, a facility operated by the U.S. Geological Survey. After working as a volunteer in coastal resource management for the Peace Corps, followed by a two-year stint at the U.S. State Department, she decided to pursue her interest in marine food webs. She happily accepted a graduate-school position at Chapple’s Big Fish Lab at OSU, where she jumped into shark research in 2021.
Capturing the young sevengill in Puget Sound has added a level of excitement to shark research and lends some credence to the concept of Puget Sound being a nursery, a place where newborn sharks grow until they are old enough to migrate, she said. Still, a single juvenile is just one shred of evidence.
“Is this an area where these sharks give birth, or did it come in from Willapa Bay?” Schulte wondered. “This is just the beginning of this project, but these are awesome possibilities.”
Sevengills in the ecosystem
Broadnose sevengill sharks have been known to feed on seals and sea lions elsewhere in the world. Schulte has captured more than 240 animals in Willapa Bay, where she has checked the stomach contents of about half of them before release. Overall analysis of the undigested prey is yet to be completed, but it will be a significant part of her final report. The boat used in Puget Sound was not equipped for checking stomach contents, although future efforts could focus more on prey species in South Sound.
Generally, sevengill sharks are considered opportunistic feeders, consuming whatever is available, including other sharks, bony fishes and marine mammals. They are considered great hunters, sometimes hunting in packs, but they have also been known to eat the dead remains of a variety of animals.
Stable-isotope analysis, a chemical assay of animal tissues, suggests that sevengills are top-level predators, at or above white sharks in the food web. This slightly higher trophic level could reflect differences in diet during early life stages of the two species. Another possible explanation is that sevengill sharks prey on seals year-round, while white sharks move between habitats, consuming seals on a seasonal basis. More research is needed to fully understand the differences in diet.
On a global scale, the broadnose sevengill shark is generally found in temperate waters. Along the West Coast of North America, it ranges from Southeast Alaska to Mexico. The shark is also found in South America, Asia, Australia and Africa. It is not, however, observed on either side of the North Atlantic.
Sevengills have been spotted in waters up to 600 feet deep, but most observations are in less than 300 feet along the coasts. Based on previous studies in Washington and California, it is believed that these sharks roam widely in winter, returning to the same estuaries in the spring to take advantage of rich food webs supported by plankton growth.
One sevengill shark tagged in Grays Harbor on the Washington coast in August 2005 was picked up on acoustic receivers in South Puget Sound during November and December that same year before heading out of Puget Sound at the end of December. The next spring, in April 2006, the same shark arrived back at Willapa Bay, just south of its original tagging location in Grays Harbor.
Besides Willapa Bay and Grays Harbor on the Washington coast, sevengill sharks have been studied extensively in San Francisco and Humboldt bays in California — areas where some sharks seem to return year after year. These could be important locations for birthing and sustaining young sharks until they reach migratory age. Whether mating takes place in these estuaries or elsewhere remains a mystery.
Interestingly, the research team working in Hammersley Inlet never caught a single bluntnose sixgill shark, a separate species recorded on video more than 250 times in waters under the Seattle Aquarium on Seattle’s waterfront. Likewise, research staff for the aquarium never spotted a single sevengill during study periods from 2002 to 2005 and from 2008 to 2015. Nor were sevengills ever caught during many decades of trawl surveys conducted by the Washington Department of Fish and Wildlife in every part of Puget Sound.
In fact, only one broadnose sevengill shark appears in state records. It was caught on April 4, 1993, by a commercial fisherman near Point Roberts at the extreme northern end of Puget Sound.
Nevertheless, sevengills are frequently caught in the Pacific Ocean along the West Coast. For conservation purposes, Washington state regulations require sport fishers to release both sevengills and sixgills. With the discovery of sevengills in South Puget Sound, new management issues are emerging for inside waters. One question is key: If new rules are proposed, should these sharks be considered rare, abundant or something in between?
“Our data suggest a seasonally consistent presence far into South Puget Sound, which has only one outlet to the north Pacific Ocean, meaning the species occupy waters of the central Salish Sea on at least a transitory basis,” writes Schulte and her fellow authors in a report published in Frontiers in Marine Science. “With their high trophic status and ecosystem impact in other locations, these findings may suggest a need to revise our understanding of ecological dynamics in the Salish Sea.”
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Story text available under a Creative Commons Attribution-NonCommercial-NoDerivs license: CC BY-NC-ND 4.0.
Related:
Broadnose Sevengill Shark (Notorynchus cepedianus), Bluntnose Sixgill Shark (Hexanchus griseus), North Pacific Spiny Dogfish (Squalus suckleyi), Brown Cat Shark (Apristurus brunneus), Thresher Shark (Alopias vulpinus), Pacific Sleeper Shark (Somniosus pacificus), Leopard Shark (Triakis semifasciata), Basking Shark (Cetorhinus maximus), Salmon Shark (Lamna ditropis)