Ever since I was scared out of my seat watching JAWS as a kid, I have loved sharks. Why? Because my fear of them based on seeing that movie (and first reading the book by Peter Benchley) motivated me to learn about them, and learning about them made me admire them and grow concerned for their welfare. It being national Shark Education Week, I bit at a reason to write about them.
JAWS tapped into a primal fear we humans share, but the truth is very very few of us are killed by sharks—on average fewer than 5 people a year. On the other hand, humans kill about 73 million sharks a year (largely because of the popularity of shark fin soup—see below), having put many species on the brink of extinction. To reiterate, that’s 73 million versus 5.
What Sharks Live in Puget Sound?
According to shark expert Dayv Lowry (yes, that’s spelled correctly), Senior Research Scientist at the Washington Department of Fish and Wildlife, we have four main shark residents in Puget Sound: Dogfish, Sixgills, Broadnose Sevengills, and Brown Catsharks.
Dogfish Sharks. Lowry told me that Dogfish Sharks are the most common here and can run in big roving schools in our waters. They are usually 2-4 feet long, sometimes reaching 6 feet. Dogfish Sharks clean up the marine ecosystem by feeding on weak fish, and they are food for people, larger sharks, and sometimes Orca. They typically live to about 30 years old but have been known to live twice that long.
Sixgill Sharks. Most sharks have five gill slits, making this species and the Broadnose Sevengill unusual. Sixgill Sharks are the biggest Puget Sound shark residents at 10 to 20 feet long. Female Sixgills birth their pups here during September and October in shallow water where little fish provide plentiful food and large predators are not likely to be lurking. This also means the mothers can become beached, and sitings of them at this time of year are not uncommon. Lowry said the data is limited, but evidence has shown that about 80 pups are born in Sixgill litters. He said Sixgills have been known to live to 90 years old. These large active predators spend much of their time in deep water, which in Puget Sound can run to about 1,000 feet. Lowry estimated that between Bainbridge Island and Seattle the deepest channel is 500-600 feet.
Broadnose Sevengill Sharks. This shark has a large thick body, with a broad head and blunt snout. Like many sharks, the Sevengill is counter-shaded, with its upper body gray or brown to blend with dark water and substrate when viewed from above and its lower body very pale to blend with sunlit water when viewed from below. Lowry told me Sevengills run about 9 to 11 feet long. Like the Sixgill, Sevengills spend much of their time in deep water cruising along the sea floor and making occasional forays to the surface. Opportunistic predators, they feed on a wide variety of sealife, including other sharks, rays, bony fishes, small whales, and seals. These sharks occasionally hunt in packs. Lowry explained that many shark species, including the Sixgills and Sevengills will gorge themselves on food to the point of massive bloating and then swim to extreme cold depths where they metabolize the food slowly and make it last as long as a few weeks at a time.
Brown Catsharks. Bottom feeders, elusive Brown Catsharks spend most of their lives in very deep water with sandy or muddy bottoms. These sharks are about 1.5 to 2 feet long and have mottled brown coloring and tender skin that makes them vulnerable to predators. They feed on small fish, shrimp, and squid. It is believed these solitary nocturnal sharks incubate a single egg for 7-12 months and then attach it to a hard underwater structure.
Great White Sharks?
Other sharks pass through our waters, including the infamous Great White. Lowry told me a Great White Shark carcass washed up a few years ago on Vashon Island, for example. He said that Salmon Sharks, common along the Washington coast, are often mistaken for Great Whites because of their similar shape and size. Lowry believes Washington coastal waters may be a nursery for Salmon Sharks, who migrate between California and Alaska. Darker than Great Whites, Salmon Sharks are powerful and agile hunters.
These immense docile plankton-eaters used to be plentiful in Puget Sound. But killing campaigns in the 1940s, ’50s, and again in the ’70s decimated their population here. Lowry explained that fishermen in Puget Sound regarded Basking Sharks as a nuisance because they would become caught in their nets. So boats were outfitted with sharp spears to gut Basking Sharks. The tactic worked so well Basking Sharks are now extinct in our waters, with the last single siting occurring off Point Defiance in about 2000. These enormous toothless sharks average 25 feet long but have been known to reach 40 feet.
Cool Shark Facts
- Most sharks give birth to live young; some lay eggs.
- Shark mothers will go into a sort of hunger strike around the time of birthing their young as a way of protecting them from matri-predation.
- Shark mothers do not “raise” their young.
- Sharks regularly lose and replace their teeth. A shark may go through 1,000 sets of teeth during its lifetime.
- You are more likely to be killed by a hornet, wasp, bee, or dog than a shark.
- A shark’s sense of smell is so keen it can detect a single drop of blood in the equivalent of an Olympic-sized pool.
- Shark inner ears can track sounds/vibrations from thousands of feet away.
- Sharks have membranes in their eyes that help them see in murky water.
- Most sharks have skin covered in small razor-sharp teeth called denticles.
- Many sharks can dislocate and protrude their upper jaw to bite and hold prey.
- The Whale Shark is the biggest fish in the world, weighing about 90,000 pounds.
- Like raptors, female sharks are almost always bigger than males.
Uncool Human/Shark Facts
- Hunger for the expensive delicacy shark fin soup has led fishing industries in Asian markets to kill millions of sharks each year, driving many to the edge of extinction.
- After sharks are “finned” they are typically dropped back into the ocean alive, unable to swim or pass water across their gills to breathe, resulting in suffocation. Ninety-five percent of their body protein as potential food is wasted.
- Sharks have survived Earth’s five mass extinctions, but because of our current rapid climate change, heavy predation, and ocean pollution, they may not survive the human-driven sixth mass extinction happening now.
Featured photo of a Broadnose Sevengill Shark courtesy of Jose Maria Perez Nunez. Photos of Dogfish Shark, Catfish Sharks, and Sixgill Shark courtesy of NOAA. Photo of Great White Shark courtesy of hermanusbackpackers. Photo of Basking Shark courtesy of Jidanchaomian.